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Messier Observing Projects

This page proposes a series of observing projects based on the Messier Objects. For each project, the season or month is identified in which the objects concerned are positioned for best visibility. However, generally objects are visible for several weeks on either side of the optimum date. In particular, objects at high northern declinations are circumpolar and therefore visible from the UK throughout the year.

Winter: Messier Objects In Orion And Lepus

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Orion is prominent during the winter months, shining brightly in the south. The constellation contains within its borders three objects listed in the Messier catalogue. All are diffuse nebulae and part of the great gas and dust cloud that covers much of the constellation. The brightest region of the cloud is around θ Orionis, a group of four stars known as the Trapezium. This region is the famous Great Nebula in Orion, M42. A smaller bright region lying just to the north of M42 and part of the Great Nebula is M43. The third Messier object in Orion is M78, a diffuse nebula lying 2.3° north east of ζ Orionis. In addition to the Messier objects, Orion contains three other interesting nebulae:

Lying south of Orion is the constellation Lepus, which holds one Messier object, the globular cluster2, M79. This object does not rise more than 13° above the horizon in the UK, so is never well-placed for observation. During January, it is due south and this is the best time to observe it.
 

Winter: Galactic Clusters Near Sirius

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There are many galactic clusters in the Milky Way close to Sirius. Five of the most conspicuous are listed in the Messier catalogue: M41 in Canis Major, M46, M47 and M93 in Puppis and M50 in Monoceros. They are due south during early evenings in February and March making this a convenient time to search for them. They all lie below the celestial equator so a good southerly aspect and a clear, dark sky is necessary to see them at their best. (This is particularly true of M93 and M41, the most southerly of the objects, at declinations 24° and 21° S respectively.)
 

Winter: Messier And NGC Objects In Auriga

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Throughout the winter months, the constellation Auriga is prominent in the night sky. It is a spectacular constellation and contains the sixth brightest star in the sky, Capella, and several deep-sky objects worthy of observation. The most prominent of the latter are the three Messier objects M36, M37 and M38. All three are galactic clusters3 easily found with binoculars and are good objects for small telescopes.

The following NGC clusters in Auriga are also worth searching out with small telescopes: NGC1664, NGC1857, NGC1907, NGC1893 and NGC2281. They are much smaller than the Messier objects and require a telescope of aperture at least 75 mm to locate. All are loose but readily identifiable with a low power eyepiece against the background star fields.
 

Cluster Diameter (arcmin) No Stars Magnitude
NGC1664 15 40 11+
NGC1857 9 45 8+
NGC1907 5 40 10+
NGC1893 12 20 9-12
NGC2281 15 30 7+

 

Spring: Three Easy Messier Objects For Beginners

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One of the problems that a beginner encounters when trying to observe Messier objects is simply locating them! Finding objects in the sky is a skill that can be acquired and developed with practice and there are pointers and techniques that will help the newcomer.

In early March, three easy-to-find galactic clusters in Messier's catalogue are well placed for observation in the early evening. One of the three, the Beehive Cluster, M44, can be found with the naked eye on a clear night. The other two objects, M67 and M48, are also bright, easy-to-locate, binocular objects. The objects provide an opportunity to practice the skills of "star hopping" which can then be applied to find the more difficult and faint Messier objects and interesting objects in the NGC catalogue.

To find a deep sky object it is necessary to employ a series of steps by which the area of sky being searched is progressively reduced until the object appears in the field of view of the main telescope. For this, a good star map is necessary. Norton's Star Atlas contains comprehensive maps of the sky down to magnitude 6.5, each accompanied by notes identifying some of the more conspicuous and interesting deep sky objects. As observing skills develop and interest increases it is worth progressing to a more detailed map such as Sky Atlas 2000. This is a large scale set of maps which shows fainter stars down to magnitude 8. For the ultimate guide to deep sky objects I think that there is nothing better than Burnham's Celestial Handbook. However, for a gentler start with just the Messier catalogue, The Messier Album by Mallas and Kreimer or Messier's Nebulae and Star Clusters by Kenneth Glyn Jones are excellent books.

A pair of binoculars is the next essential tool: 10x50 or 7x50 models are good for finding many Messier objects or at least identifying the star patterns that are used to locate the objects themselves. When using binoculars for astronomical work it is essential to have a firm mount that will hold them steady. (It is possible to use a camera tripod or a telescope mount fitted with a suitable attachment.) The need for a mounting becomes more acute the higher the magnification in use.

The final major item is of course the telescope and for deep sky work size really does count! (However, there are always interesting deep sky objects within reach whatever size instrument is in use.) The telescope will need a finder scope to facilitate alignment on the correct region of sky once it has been identified. Also required is a low power eyepiece with a wide apparent field of view, ideally respectively 50x magnification and 1°. For example, for a telescope with an objective (lens or mirror) with focal length 120 cm, an eyepiece with focal length 25 mm and apparent field of view of 50° would be ideal. Some deep sky objects respond well to higher magnification and additional shorter focal length eyepieces will be useful to observe them. Again for deep sky observing, eyepieces with large apparent fields will generally give the most rewarding views. The telescope needs to be firmly mounted, ideally on an equatorial mount with the polar axis correctly aligned to the celestial pole.

By way of illustration of the steps involved in finding a deep sky object, consider M44, a bright galactic cluster in Cancer. Mid-evening (~9.30pm) around the middle of March, the constellation is due south. The first step in finding an object is to identify the general direction in which to look, so start by facing south: Cancer lies straight ahead, with Leo to the east of it, Gemini to the west, Orion further west towards the horizon, and the Plough high overhead, close to the zenith. Use Norton's Star Atlas (or another good star map) to identify the individual stars forming the constellation Cancer. The first thing to note about Cancer is that it is not prominent! The brightest stars are only magnitude three and there are only two such. In fact, it is only the presence of M44 and M67 and the fact that Cancer is a zodiacal constellation that mark it out at all. If it is a particularly clear night, the eye might be automatically drawn to M44 as a faint misty patch lying between two of Cancer's brighter stars. If however there is any mistiness, light pollution or interfering moonlight, M44 may be invisible to the unaided eye.

Assuming that M44 is not immediately visible, the next step in narrowing down the search is to find suitable guide stars. The star map shows that M44 is located between the 4th magnitude stars γ and δ Cancri which in turn lie just over one third of the distance along a line from Pollux in Gemini to Regulus in Leo. Pollux and Regulus are both first magnitude stars, easily identifiable to the naked eye. Using binoculars, or with the naked eye if it is clear enough, scan along the line from Pollux to Regulus to find γ and δ Cancri; once these are visible in binoculars, M44 should also be easily visible. But assuming that M44 requires a little more searching, note from the star map that it forms a shallow triangle with γ and δ Cancri and lies slightly west of the line connecting the two stars. Place the lowest power (widest field of view) eyepiece in the telescope and, using the finder, align the telescope to the position of γ and δ Cancri identified in the binoculars. Remember that telescope finders usually invert the image and a mental rotation needs to be made when comparing finder and telescope views with binocular/naked eye views! M44 should be visible in the finder, so centre the finder on it and (assuming that the finder is correctly aligned with the main instrument!) M44 will appear in the field of view of the main instrument. M44 is a large object, about 1° in diameter, and really needs a large field of view to been seen in its entirety to good effect. I always think that it is more impressive in binoculars than in a telescope.

Having successfully found M44, the next object is M67, a fairly rich galactic cluster also in Cancer. Having previously found γ and δ Cancri it is possible now to use these stars as pointers to M67. On the star map continue a line through these two stars southwards for a distance almost twice their separation. To the east of this point lies the star α Cancri. Find this star with binoculars and note the three stars 60, 50 and 45 Cancri forming a shallow arc to the west of it. Note that, on the star map, M67 lies midway between 60 and 50 Cancri. Identify and note this position in the sky using binoculars. If it is dark and clear, M67 will be easily seen in binoculars at this position; if it is misty or there is light pollution or glare from the Moon then the telescope will be required to see it. Align the finder to the position noted with binoculars (remembering the mental inversion) centre this position, or M67 itself if it is visible, and again the object should appear in the field of view of the main instrument.

The final object, M48, lies in a relatively barren area of sky and therefore may be a little more difficult to find. However there are several good guide stars that aid in locating it. The primary pointers for M48 are Procyon in Canis Minor and β Canis Minoris, lying about 4° to the north-west of Procyon. Locate these two stars on the star map and project a line south east about 12° or three times the separation of Procyon and β. This almost exactly pinpoints the position of M48 just east of the Hydra-Monoceros border. On the star map note three stars forming a triangle around M48 with the cluster approximately in the centre. The north west star is ζ Hydrae, the north east "star" is, in fact, a small group of three formed from 2, c and 1 Hydrae. The southern member is a fainter sixth magnitude star.

Use binoculars to find and centre the triangle of stars around M48. If it is clear and dark, M48 should be easily visible as a small misty patch. If it is misty or hazy or there is light pollution then M48 may not be visible. Use the finder to position the telescope on the same region of sky as the binoculars. With the lowest power, widest field eyepiece check the telescope to see if M48 is visible. If not move the telescope slowly and in turn north, south, east and west by an amount up to about ¾ of the field of view. While searching in this way, always return and re-centre the telescope on the original position before moving in a new direction. The area of sky covered by this movement should be more than enough to find the object if the original positioning was a little off centre. Once M48 is located, a higher power eyepiece can be substituted to study it.
 

Spring: Messier Objects In Ursa Major

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The constellation Ursa Major, the Great Bear, lies almost overhead during spring. It is a rich area for deep sky observers containing many faint galaxies within reach of amateur telescopes. It contains seven objects listed in the expanded version of Messier's catalogue: M40, M81, M82, M97, M101, M108 and M109. Ursa Major is the best known of all constellations and all its Messier objects are fairly easy to find. Why not spend a pleasant spring evening hunting for them?
 

Spring: Messier Objects In Canes Venatici

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Canes Venatici is a faint constellation lying south of Ursa Major, the Great Bear. It contains five Messier objects within its boundaries, all of which are worth searching for and observing with small or moderate telescopes:

All five Messier objects are easy to find with binoculars in good dark skies. Unfortunately, light pollution will have a significant deleterious effect on the visibility of features.
 

Spring: A Group Of Galaxies In Leo

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The constellation Leo rides high on the meridian during early evenings in April. Within the constellation is a cluster of three galaxies that form an interesting group for small telescopes: M65, M66 and NGC3628. The three lie at a distance of approximately 29 million light years and have diameters between 50,000 and 60,000 light years.

The group lies approximately midway between θ and ι Leonis. On a clear dark night, it is possible to locate M65 and M66 with 10x50 binoculars. (M66 is the brighter of the two.) NGC3628 is on the threshold of visibility with 10x50 binoculars, so will only be seen on exceptional nights. A telescope with a low power and a field of view of approximately 0.75° is necessary to see all three galaxies together in the field of view. A telescope of 250 mm aperture with a low power, wide field eyepiece will provide a fine view of the group, showing hints of spiral structure in M66 and revealing the elongated shapes of M65 and NGC3628, indicating their edge-on orientation.
 

Spring: Deep Sky Objects In Coma Berenices

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Coma Berenices is a small, faint constellation lying between Boötes to the east, Leo to the west, Virgo to the south and Canes Venatici to the north. α Comae is the brightest star in the constellation; at magnitude 4.23 it is a binary pair with two almost identical components. The plane of the orbit of the components is almost edge-on to the Earth, and the separation of the stars varies from effectively zero to a maximum of 0.9 arcseconds. The orbital period is 25.85 years and the separation is currently increasing from minimum in 2007.

The Coma star cluster is probably the best known naked eye cluster after the Pleiades and Hyades in Taurus. It has an apparent diameter of about 5° and therefore is best viewed with good binoculars. The cluster contains five stars brighter than magnitude 5 with a further 32 fainter stars identified as true members of the cluster. The brighter stars of the cluster are approximately 50 times brighter than the Sun while the faintest members (magnitude 11) have luminosities approximately one-third that of the Sun. The cluster lies 250 light years distant and is one of the closest galactic clusters with only the Hyades and the Ursa Major group lying closer. It has a diameter of approximately 22 light years.

Although Coma does not appear impressive to the naked eye and, in fact, is indistinct in comparison with its prominent immediate neighbours, it contains 68 NGC objects within its boundary and therefore offers much to the deep sky observer. The NGC objects are mostly members of the Virgo Cluster of galaxies. Only three of the NGC objects in Coma are not galaxies: two are globular clusters and one (NGC5053) is a rather peculiar cluster somewhere between globular and a very condensed galactic. Of the 68 NGC objects, seven are listed in the Messier catalogue: six of these are galaxies (M64, M85, M88, M98, M99 and M100) and one is a globular cluster (M53).

There are many other galaxies in the neighbourhood of Coma, and it is possible to spend many pleasant hours exploring them. Visual observations generally yield pale, featureless patches of light and only CCD images reveal significant detail. However, this should not detract from searching out and studying these fascinating, distant objects with amateur telescopes when conditions are good and skies are dark.
 

Summer: Messier Objects In Virgo

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A challenge for the light evening skies of June is to explore the Virgo cluster of galaxies and search out the eleven Messier objects that reside within the boundaries of the constellation: M90, M89, M87, M86, M84, M58, M59, M60, M49, M61 and M104. (The order in which the objects are listed is the natural order of "star hopping" from one to another, starting with the most northerly, M90.) All eleven objects are galaxies and are accessible in moderate telescopes; to find them takes a good star map and a little skill! There is a good finder chart of the main Virgo cluster in Burnam's Celestial Handbook, Vol. 3.
 

Summer: Globular Clusters

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  Hercules.gif

During June and July, with twilight extending beyond 22:00 BST, observers of deep sky objects need to stay up late if they want to see their favourite objects against a dark sky. There are no less than 11 globular clusters listed in the Messier Catalogue that are near the central meridian in late evenings during the month of June. In descending order of declination they are:

If you are lucky enough to have a clear, dark southern aspect to your observing site then June and July are good months to observe these Messier objects: good hunting!

July: Messier Objects For Late Evenings

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Late on balmy July evenings, once the sky has become truly dark, four Messier objects are visible in the adjacent constellations of Lyra and Hercules, relatively close to the zenith and therefore well placed for observers using Newtonian reflectors. (The objects are rather more awkward for observers using binoculars or refractors without a star diagonal!) The objects are three globular clusters (M13, M56 and M92) and the famous Ring Nebula, M57. M13 and M92 are in Hercules; M56 and M57 are in Lyra.
 

Summer: Southerly Messier Objects - An Observing Challenge

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The summer months offer a chance for evening observation of some of the most southerly of the Messier objects. To observe them successfully, it is necessary to have an unobstructed southerly horizon, clear skies, good seeing and, of course, no light pollution. For the majority of UK observers this is an unlikely combination of circumstances! However if you wish to complete your set of observations of the Messier objects, the most southerly members do need to be observed.

The group of most southerly Messier objects described here consists of two galactic clusters, M6 and M7, and five globular clusters, M54, M55, M62, M69 and M70. All seven objects are situated below -30° declination and therefore present a real challenge for observers in the UK. The most southerly of the seven, M7, has a declination of -35° and rises only 3° above the horizon from Orwell Park Observatory! However, although all the objects are very difficult to locate from UK latitudes, once found they provide the satisfaction of a challenging observation!
 

Summer: Messier Objects In Ophiuchus And Serpens

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The large constellation Ophiuchus contains six Messier objects, all of which are globular clusters: M9, M10, M12, M14, M19 and M62.

Ophiuchus splits the constellation Serpens into two parts: the north-western part is known as Serpens Caput and the south-easterly, Serpens Cauda. Serpens Caput contains the magnificent globular cluster M5. Serpens Cauda contains M16, a large scattered open cluster embedded in a huge diffuse nebula.
 

Summer: Deep Sky Objects In Scutum

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The constellation Scutum is well placed for early-evening observation during the warm nights of summer. It is a small constellation, measuring only some 9x12° and contains only one star above 4th magnitude, α Scuti, at magnitude 3.85, and only six stars above 5th magnitude. Although small and not endowed with bright stars, it lies in a rich part of the Milky Way, offering lovely star fields for binocular observers and contains within its borders eight NGC objects, two of which are also Messier objects, namely M11 (the beautiful Wild Duck Cluster) and M26.

The non-Messier NGC objects in Scutum are:

Summer: Deep Sky Objects In Sagittarius

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Sagittarius is a large constellation visible towards the southern horizon in late summer. The Milky Way runs through the western part of the constellation. Sagittarius contains rich star fields, but because of its southern declination, these are poorly seen from the UK. Seven of the Messier objects in Sagittarius most easily visible from the latitude of the UK are as follows:

Late Summer: Deep Sky Objects In Cygnus

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During the warm nights of August, Cygnus, The Swan, can be seen gliding overhead. Lying within the arms of the Milky Way, the constellation contains many rich star fields and nebulous regions and is well worth searching with binoculars on a clear dark evening. As the year draws on into September, the earlier darkening of the sky means that Cygnus is still prominent overhead shortly after sunset.

Despite its rich stellar background, Cygnus contains only two objects listed in the Messier Catalogue, M29 and M39, both galactic clusters. However, it is particularly rich in other deep sky objects, for example Burnham's Celestial Handbook lists eleven planetary nebulae in the constellation. Five of the best deep sky objects in Cygnus are:

Late Summer: Seven Messier Objects

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The Summer Triangle defined by Vega in Lyra, Deneb in Cygnus and Altair in Aquila is high overhead and dominates the southern aspect of the sky during September evenings. During September, the evenings are drawing in and deep sky observing becomes more practical once more. The following seven Messier objects are well located for observation on September evenings; the first five are located within the boundaries of the Summer Triangle, the sixth in Hercules and the seventh in Sagitta:

All seven objects provide fine viewing in small telescopes and are easy to find. (The only difficulty may be making certain that M29 and M39 are properly identified against the wealth of star fields and condensations in the Milky Way!)
 

Autumn: Two Nebulae In Pegasus

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The constellation Pegasus culminates in early evening in October. It contains one splendid Messier object, the globular cluster M15, and many faint galaxies.

The brightest galaxy in Pegasus is NGC7331 shown in Norton's Star Atlas under the Herschel catalogue number 53. It has an apparent magnitude of 10.4 and is visible in a 75 mm telescope as a faint elongated misty patch. In a 250 mm telescope it is seen as an elliptical patch of light about 10'x2'. The galaxy is often shown in photographs in astronomy books as a view of how the Milky Way, our own galaxy, might appear if viewed from intergalactic space. NGC7331 is a large galaxy similar in structure to the Andromeda Galaxy M31. It lies at a distance of about 50 million light years and has a diameter well over 100,000 light years. The total luminosity is estimated to be about 50,000 million suns with a mass of about 140,000 million suns.
 

Autumn: Messier Objects In Aquarius

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The constellation Aquarius culminates in early evening in October. Although it is a large constellation it contains only three Messier objects: M2, M72 and M73. M2 and M72 are globular clusters. M73 is not a true cluster but a small grouping of four stars.

Aquarius also contains two interesting objects not in Messier's catalogue:

Winter: A Selection Of Galactic Clusters In Cassiopeia

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In November, Cassiopeia lies near the zenith in the early evening sky and this provides a good opportunity to search for some of the many deep sky objects within its boundaries. Lying in the Milky Way, Cassiopeia is particularly rich in galactic clusters (although only two are listed in the Messier catalogue - M52 and M103). For this observing project I have selected six objects: the two previously mentioned Messier objects plus NGC7789, a particularly rich cluster that is a fine sight in moderate telescopes, and a grouping of three NGC objects (NGC654, NGC663 and NGC659) which are not particularly spectacular but can be easily located once M103 has been found.

Lying about 2.5° SSW of β Cassiopeiae is NGC7789. This is a very rich cluster containing as many as 1000 stars from magnitude 11 and fainter. It is visible in binoculars as a faint misty patch with no stars resolved. A 75 mm telescope will show a sprinkling of stellar points against the misty background with every increase in aperture resolving more stars. In a 250 mm telescope on a clear dark night NGC7789 is a truly splendid sight. It is considered to be at an intermediate stage between a true galactic cluster and a globular cluster. It is much older than typical galactic clusters with its brightest members being orange giant stars rather than the more usual blue giants of the latter. Its age is estimated to be between 1.0 and 1.5 billion years, older than most galactic clusters but much younger than globular clusters which are 10 billion or more years old.

Lying about 1.5° to the east of M103 in an arc to the south are the three clusters NGC654, NGC663 and NGC659. NGC663 is by far the most conspicuous of the three with about 80 stars from magnitude 9 contained in an angular size of 11'. It lies at a distance of 2600 light years giving a diameter estimated at around nine light years. NGC654 is the next most easily visible of the trio; it is about 5' in diameter and contains about 50 stars in the magnitude range 11 to 14. It is estimated to be about 8000 light years distant and would therefore have a true diameter around 12 light years. The final cluster of the trio is rather faint and small with about 30 stars from magnitude 12 in a diameter less than 4'. Its distance is estimated to be about 6000 light years and its diameter seven light years. NGC663 can be found easily on dark clear nights with a 75 mm telescope but the other two clusters require at least a 150 mm aperture to clearly distinguish them from the general background of Milky Way stars.

In general all the preceding objects require good dark skies. If the Milky Way is not visible with the unaided eye due to mist or sky glow then they will not be seen well in the telescope due to reduced contrast and light loss. However on good clear nights they will amply repay the effort to locate them.
 

Winter: Some Messier Objects

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  Psc_Cet.gif

There are eight Messier objects lying in the range 0-3 hours of RA, presenting a southerly aspect during early evenings in winter. The objects are:

All the objects, apart from M77 in Cetus, are north of the celestial equator and M77 is only a few arcminutes south, so all are well-placed for observation in winter.

The Andromeda Nebula, M31, is the most distant object that can readily be seen without optical aid, lying at a distance of 2.2 million light years. (Some people claim to be able to see with the naked eye M33 in Triangulum at a distance of 2.35 million light years, but most people require binocular assistance for this!) Binoculars are an excellent instrument to observe M31. On very clear, dark, moonless nights the faint outline of the galaxy can be traced out to three or four degrees diameter, 6-8 times the diameter of the full moon! With a telescope, low powers are needed, otherwise the faint glow of the nebula becomes an indistinguishable background for the foreground stars of our own galaxy and only the bright nucleus is clearly visible. In a 250 mm telescope on a good, clear night some of the dust lanes in M31 are discernible.

M31 has four smaller satellite galaxies two of which (M32 and M110) are close to it and visible in a 75 mm telescope. M32 is the brighter and smaller of the pair. M110 is dimmer and larger and can be difficult for a 75 mm instrument, although I have seen it on several occasions with a 70 mm Maksutov telescope. The other two satellite galaxies are not in the constellation of Andromeda but lie approximately 7° to the north of M31 in the constellation Cassiopeia. They are NGC185 and NGC147: both are much fainter and require a 150 mm telescope to observe them.

Footnotes

[1]

A planetary nebula is an emission nebulae with a visual appearance that is generally round or slightly elliptical in shape. It comprises a shell of gas surrounding a very hot central star. The surface temperature of the star can be up to 100,000 K (by way of comparison, the Sun has a surface temperature of 5,800 K). The extreme surface temperature means that most of the radiation leaving the star is in the ultraviolet region of the spectrum. Radiation from the star excites the atoms in the gas cloud causing it to glow in visible light. A planetary nebula has no resemblance to a planet other than its generally circular or elliptical shape! Planetary nebulae can be interesting objects for the amateur astronomer to find and observe and many are within the range of small telescopes (although as with all deep sky objects, a larger telescope will show a larger number of objects.) A good starting point for finding and observing planetary nebulae is Burnhams Celestial Handbook (in three volumes), by Robert Burnham Jr., Dover Publications, Inc., 1978; it lists all the brighter and more interesting nebulae for each constellation.

[2]

Globular clusters are distant and ancient aggregations of stars that form a spherical "halo" surrounding the galaxy. A typical globular cluster contains of the order of 100,000 stars with the larger clusters containing upwards of one million. They are called "globular" because of their spherical and condensed appearance in telescopes. However, the typical diameter of a globular cluster is 150 light years and even in the larger clusters containing perhaps one million stars, the average distance between stars, even in the condensed central region, is about one light year. The best known example of a globular cluster is M13 in Hercules, easily visible in binoculars or a small telescope (in fact visible to the naked eye on clear nights). Globular clusters were formed early in the life of the Universe, and contain old stars. The majority of globular clusters lie within 60,000 light years of the galactic centre and there are approximately 150 in orbit around the Milky Way galaxy. Globular clusters have also been identified around other galaxies.

[3]

Galactic clusters (also referred to as open clusters) are loose aggregations of stars that typically contain between 20 and a few thousand stars. The best known examples visible to the naked eye are the Pleiades and the Hyades, both in Taurus. Astronomers have identified approximately 1200 galactic clusters in total. Galactic clusters are found in or close to the plane of the galaxy. Stars in galactic clusters tend to be bound less tightly than those in globular clusters. As a result of these factors, the differential rotation of the galaxy tends to disrupt galactic clusters, and calculations suggest that many will not survive more than one or two orbits of the galaxy. As a result, most galactic clusters are young: some (e.g. NGC2263) are less than 10 million years old and are still undergoing star formation.

The Messier Objects

Below, coordinates are specified with respect to epoch J2000.0.

M#

Location

Description

M1
RA: 5h 34.5m,   dec: +22° 01'.

Constellation: Taurus.

M1 is located 1° N and 1° W of the 3rd magnitude star ζ Tauri. It can be detected in a 75 mm telescope on a dark clear night but, it is faint, as a result of which an aperture of at least 150 mm is required to show its oval shape. In a 250 mm telescope some faint detail can be discerned.

Size: 6'x4'.

Magnitude: 8.0.

Distance: 6500 ly.

Object: supernova remnant.

John Bevis (a British amateur astronomer) discovered M1 in 1731. Messier found it independently on 12 September 1758, while looking for the first predicted return of Halley's Comet.

The Earl of Rosse at Birr Castle, Ireland observed M1 in 1844 with a 91 cm reflector. He described it as having claw-like appendages, as a result of which, the name Crab Nebula began to be used. However, when, in 1848, the Earl turned a 183 cm reflector (the so-called Leviathan of Parsonstown) onto the object, he repudiated his earlier description. Nevertheless, the name stuck!

M1 is the remnant of a supernova which erupted on 04 July 1054. Chinese and Japanese astronomers observed it, calling it a guest star. Its peak magnitude was approximately ‑5 and it was visible in daylight for 23 days and visible to the naked eye until April 1056. M1 was a Type II supernova - meaning that hydrogen was present in its spectrum. The precursor star of a Type II supernova is typically a red giant of diameter 10 AU (i.e. similar in size to the orbit of Saturn) with a hydrogen-rich envelope. The likely trigger of the supernova is core collapse: the stellar core burns through to iron which cannot generate energy by nuclear fusion, then collapses to form a neutron star. The collapse stops when the neutron star forms, causing high pressure and temperature in the region just above its surface, which drives a shock-wave into the outer layers. This results in the ejection of several solar masses worth of material at speeds of up to 5000 km/s.

M1 is currently a turbulent expanding mass of gas and dust some 13 light years across. It is expanding at 1300 km/s. Images taken several months apart show movement of the filaments. At the centre of M1 lies a magnitude 16 pulsar (the Crab pulsar), a rapidly rotating superdense neutron star only circa 6 km in diameter but with mass greater than the Sun. A single cubic centimetre of material from the Crab pulsar would weigh half a billion tonnes! The period of the pulsar is 0.0331 seconds, slowing by 10 ms pa. The object emits radiation at all frequencies and it powers the entire nebula: as it spins its intense magnetic field whips around, acting like a sling shot, accelerating subatomic particles and sending them hurtling into space at close to the speed of light. The pulsar loses energy as the highly energetic electrons spiral along magnetic field lines and emit synchrotron radiation. The pulsar emits radiation at all frequencies, specifically much more at X-rays than in visible light. The ultraviolet component of radiation ionises gas in the filaments of the M1 nebula causing them to glow.

M2
RA: 21h 33.5m,  dec: -00° 49'.

Constellation: Aquarius.

M2 can easily be found 4.5° N of β Aquarii.

Diameter: 13'.

Magnitude: 6.5.

Distance: 55,000 ly.

Object: globular cluster.

M2 is a fine, bright globular cluster. It is a visible in binoculars and small telescopes as a little fuzzy ball. It requires a 200-250 mm telescope to provide resolution of the outer edges. It contains at least 100,000 stars within a diameter of about 170 light years. If the Sun were placed at the distance of M2, it would appear as a 21st magnitude star visible only in the world's largest telescopes!

M3
RA: 13h 42.2m,  dec: +28° 23'.

Constellation: Canes Venatici.

M3 lies on the southern border of Canes Venatici in an area of sky with no bright stars. It is most easily found using binoculars. First locate β Coma Berenices then move at the same declination about 6° E onto a line connecting Arcturus and α Canum Venaticorum. M3 should be close to the centre of the field appearing as a fuzzy "star" of magnitude about 6. Having located M3 in this way, it should he easy to find with a telescope for a more detailed examination.

Diameter: 16'.

Magnitude: 6.2.

Distance: 48,500 ly.

Object: globular cluster.

Messier discovered the globular cluster M3 in 1764. In a 75 mm telescope it appears as a bright central region fading to a faint glow at the edges, but no real resolution is possible. At least a 100 mm aperture is required to show resolution at the outer edges. Further increases in aperture enable more stars to be discerned against the bright background of unresolved stars. With a 250 mm aperture, good dark skies and high magnifications, stars ran be resolved against the bright background right to the centre of the cluster.

M3 contains at least 45,000 stars in a diameter of approximately 220 light years. It shines with a luminosity about 160,000 times that of the Sun. At the distance of the cluster, the Sun would be visible as an extremely faint object at magnitude 20! All the stars visible in M3 in telescopes are giant stars much more luminous than the Sun.

M4
RA: 16h 23.6m,  dec: -26° 32'.

Constellation: Scorpius.

M4 is located approximately 1.3° W of Antares (α Scorpii). It is easily found in binoculars and under ideal conditions can be seen with the naked eye.

Diameter: 26'.

Magnitude: 5.9.

Distance: 10,000 ly.

Object: globular cluster.

M4 is a fine globular cluster. A 100 mm telescope will resolve some stars, although generally a larger instrument is beneficial from the latitude of Suffolk. M4 is visually one of the largest globular clusters, with an apparent diameter of around 20' and a central condensation around 10-12' in diameter. It is a loose cluster and from southerly latitudes in a telescope of 250 mm or larger is a magnificent sight showing many faint stars forming loops and streamers. If M4 were situated further north, it would rank with M13 as a magnificent object visible for observers in the northern hemisphere. It is some 50 light years in diameter.

M5
RA: 15h 18.6m,  dec: +02° 05'.

Constellation: Serpens Caput.

M5 lies in a sparse area of the sky, but is not difficult to find. The best way is to first locate the pair of 4th magnitude stars 109 and 110 Virginis lying SE of Arcturus (α Boötis). About four degrees east of 110 Virginis, the most easterly star of the pair, is a small triangle of 5th magnitude stars, 5, 6 and 10 Serpentis. M5 lies just to the NW of the most northerly star of the triangle, 5 Serpentis, and is visible as a fuzzy "star" in binoculars (it is not visible to the naked eye).

Diameter: 17'.

Magnitude: 5.7.

Distance: 23,500 ly.

Object: globular cluster.

The globular cluster M5 joins M13 and M3 as one of the three best globular clusters in the northern hemisphere. It is a fine sight even in a small telescope and is well worth looking for. In a 75 mm telescope it is a bright round object about 5' in diameter but without resolution of the stars. A telescope of 100 mm aperture will begin to resolve the brightest stars in the cluster and an aperture of 250 mm will show M5 magnificently, resolving stars to the centre of the cluster. The cluster has a diameter of about 150 light years and contains over half a million stars.

M6
RA: 17h 40.1m,  dec: -32° 13'.

Constellation: Scorpius.

M6 lies 2.5° S and 2° E of the 4th magnitude star 45 Ophiuchi. Unfortunately, for observers in the UK, the very southern declination of M6 makes it a real challenge to find unless observing from a site with a flat southern horizon, no light pollution and an exceptionally clear sky. Given such circumstances, the search is most effectively carried out with a pair of good binoculars.

Diameter: 15'.

Magnitude: 4.2.

Distance: 1300 ly.

Object: galactic cluster.

M6 is a bright, loose galactic cluster which contains about 130 stars in the magnitude range 6.2 to 14. It lies in a rich area of the sky and several clusters or condensations of stars in the Milky Way lie nearby. However M6 is by far the most prominent object and once found cannot be mistaken.

M7
RA: 17h 53.9m,  dec: -34° 49'.

Constellation: Scorpius.

M7 is best found with a good pair of binoculars. It lies 2.5° N and 4° E of λ Scorpii.

Diameter: 80'.

Magnitude: 3.3.

Distance: 800 ly.

Object: galactic cluster.

M7 is a bright cluster in Scorpius lying about 3.5° SE of M6. It contains 80 stars in the magnitude range 7 to 10; it is a large cluster and significantly brighter than M6. However, it is 2.5° further south than M6 (in fact, it is the most southerly of all the Messier objects) and is therefore very difficult to observe from the UK.

M8
RA: 18h 03.8m,  dec: -24° 23'.

Constellation: Sagittarius.

M8 is visible to the naked eye. Continue the arc of stars ζ, φ and λ Sagittarii another 5° to the WNW.

Size: 90'x40'.

Magnitude: 6.0.

Distance: 4850 ly.

Object: galactic cluster.

M8 is known as the Lagoon Nebula. In binoculars or a small telescope, it appears as a slightly nebulous cluster of stars. Larger aperture instruments will display considerable detail. The cluster contains many irregular variable stars.

M9
RA: 17h 19.2m,  dec: -18° 31'.

Constellation: Ophiuchus.

M9 lies 3° S and 2° E of η Ophiuchi (magnitude 2.5).

Diameter: 9' (depending on how many outlier stars are included).

Magnitude: 7.7.

Distance: 25,800 ly.

Object: globular cluster.

M9 is a visually small cluster which appears slightly oval in shape. In small telescopes, it appears as a slightly oval patch without resolution into stars. Even with a 250 mm reflector, it is not fully resolved, although there is a hint of resolution under ideal conditions. M9 is one of the closest globular globular clusters to the galaxy and has a diameter of about 45 light years.

M10
RA: 16h 57.1m,  dec: -04° 06'.

Constellation: Ophiuchus.

M10 is located 1° W of the 5th magnitude red star 30 Ophiuchi. It can be found with good binoculars.

Diameter: 15'.

Magnitude: 6.6.

Distance: 16,300 ly.

Object: globular cluster.

M10 is brighter and more condensed than M12 (also in Ophiuchus) and some find it an easier cluster to resolve. A 100 mm telescope will reveal some resolution under ideal conditions while a 200 mm telescope will provide fine views. M10 has a diameter of about 40 light years.

M10 and M12 are only approximately 2000 light years apart and, to a hypothetical observer situated in either cluster, the other would appear as a glorious, naked eye, 2nd magnitude object with a diameter about three times that of the full moon!

M11
RA: 18h 51.1m,  dec: -06° 16'.

Constellation: Scutum.

M11 is easy to locate lying ESE of β Scuti and forming a right angle with that star and λ Aquila about 4° to the E.

Diameter: 14'.

Magnitude: 5.8.

Distance: 5500 ly.

Object: galactic cluster.

M11, known as the Wild Duck Cluster, is one of the most beautiful galactic clusters in the sky. It can be seen with the naked eye under ideal conditions. It is easily located in binoculars, looking very like an unresolved globular cluster. A 75 mm aperture telescope reveals its true nature, resolving many stars against a misty twinkling background. As magnification and aperture increase, the cluster is resolved into a magnificent display of hundreds of stars.

The cluster is slightly triangular in shape with the majority of stars lying inside a 12' diameter circle. M11 is estimated to contain as many as 2900 stars. The brightest stars are giants, of visual magnitude 10-11, the most luminous of which are over 100 times as powerful as the Sun. At the distance of M11 the Sun would appear as a 16th magnitude star! M11 is highly condensed for a galactic cluster, with most of its members lying within a sphere of diameter 15 light years. Such densities are as great as those of some of the "looser" globular clusters. At the centre of M11, the density is such that an observer on a hypothetical planet orbiting a star would be able to see several hundred stars brighter than 1st magnitude with the very brightest being of magnitude -6.5!

M12
RA: 16h 47.2m,  dec: -01° 57'.

Constellation: Ophiuchus.

M12 is located 2° N and 2° W of M10.

Diameter: 15.

Magnitude: 6.7.

Distance: 19,000 ly.

Object: globular cluster.

M12 is visible in binoculars but is sometimes difficult to resolve in small telescopes. However, under ideal conditions a 100 mm telescope will begin to resolve stars at the edges and a 250 mm telescope will provide fine views. M12 has a diameter of about 50 light years.

M13
RA: 16h 41.7m,  dec: +36° 28'.

Constellation: Hercules.

M13 is easily found in binoculars as a fuzzy 6th magnitude "star" and can even be discerned by the naked eye under good conditions. It is located S of η Herculis about one third of the distance along a line extended from η to ζ Herculis.

Diameter: 17'.

Magnitude: 5.8.

Distance: 26,000 ly.

Object: globular cluster.

M13 is a large globular cluster containing over one million stars. It shines with the light of 300,000 Suns and has a total mass of half a million Suns. It is a magnificent object for any size of telescope. A 100 mm aperture will begin to resolve the brighter stars and every increase in aperture will yield a view that is more spectacular. In a 250 mm aperture M13 is a superb sight showing some of the streamers of stars that appear to radiate from the central condensation. The apparent diameter of the cluster, estimated from photographic plates, is about 23' however, visually most of the brighter portion of the cluster lies within a region about 10' in diameter. M13 is estimated to have a diameter of 160 light years.

M14
RA: 17h 37.6m,  dec: -03° 15'.

Constellation: Ophiuchus.

M14 is 2° N and 3° E of the star 99 Ophiuchi.

Diameter: 12'.

Magnitude: 7.6.

Distance: 24,000 ly.

Object: globular cluster.

Good binoculars or a small telescope will reveal M14 as a fuzzy "star". However, it is much more difficult to resolve than M10 and M12 (also in Ophiuchus) and requires an aperture of at least 250 mm to reveal a hint of stellar structure. It has a diameter of about 40 light years.

M15
RA: 21h 30.0m,  dec: +12° 10'.

Constellation: Pegasus.

M15 is easily seen in 10x50 binoculars as a fuzzy "star" at the W edge of Pegasus about 4° NW of ε Pegasi.

Diameter: 12'.

Magnitude: 6.2.

Distance: 49,500 ly.

Object: globular cluster.

M15 is a beautiful, bright globular cluster, amongst the finest in the northern skies. It has a bright, dense core and is more condensed than many globular clusters. A 75 mm telescope will achieve limited resolution of stars at the edges on a good dark night. A 150 mm telescope will provide partial resolution of the cluster and a 250 mm telescope will resolve stars fairly well to the nucleus and provide a glorious view of the cluster. M15 has a luminosity 200,000 times that of the sun. The diameter of the cluster is 130 light years.

M15 has been found to be a source of X-radiation and probably contains at least one supernova remnant. It has been suggested that the supernova remnant could be a black hole. The cluster also contains the planetary nebula K648. (The object is of diameter 3 arcsec and, at magnitude 13.8, is too faint for most amateur telescopes. It was discovered by F G Pease on plates taken with the Mount Wilson 250 cm telescope in 1927.)

M16
RA: 18h 18.8m,  dec: -13° 47'.

Constellation: Serpens Cauda.

M16 lies at the SE corner of Serpens Cauda. To find it move 1° N and 2.5° W of δ Scuti.

Diameter: 7'.

Magnitude: 6.0.

Distance: 5870 ly.

Object: gaseous emission nebula and associated galactic cluster.

M16 is a galactic cluster embedded in a vast, diffuse gaseous emission nebula. Under ideal conditions, a 150 mm telescope will reveal the existence of the nebula while a 250 mm will show a dark triangular wedge protruding from the N into the bright nebulosity. Long exposure photographs reveal the surrounding nebula to be spectacular. Unfortunately, M16 is at southerly declination which, combined with light summer skies, means that it is rarely well-seen from the UK. In fact, any size of telescope under seeing conditions typical in the UK will reveal only the stars of the embedded cluster, and not show the surrounding nebula at all. The nebula is estimated to be some 70,000 light years across. Like the Orion Nebula (M42) this huge cloud of gas is the birthplace of new stars; some members of the cluster might have been shining for as little as 50,000 years.

M17
RA: 18h 20.8m,  dec: -16° 11'.

Constellation: Sagittarius.

M17 is located approximately 1.5° S and 2° W of δ Scuti.

Size: 46'x37'.

Magnitude: 7.0.

Distance: 5870 ly.

Object: gaseous emission nebula in Sagittarius.

M17 is a beautiful bright, diffuse nebula also known as the Swan or Omega nebula because of its distinctive shape. The shape can be discerned in good binoculars and the object is magnificent in a telescope at low powers.

M18
RA: 18h 19.9m,  dec: -17° 08'.

Constellation: Sagittarius.

M18 is located 1° S and slightly W of M17. It is inconspicuous.

Diameter: 9'.

Magnitude: 6.9.

Distance: 4900 ly.

Object: galactic cluster.

M18 is a small open cluster of about 20-30 stars appearing as a small, fuzzy patch in binoculars.

M19
RA: 17h 02.6m,  dec: -26° 16'.

Constellation: Ophiuchus.

M19 is easy to find, lying 8° E of Antares.

Diameter: 14'.

Magnitude: 6.8.

Distance: 22,500 ly.

Object: globular cluster.

M19 is a slightly larger cluster than M80 and M9 which lie nearby. A 150 mm telescope will generally show a hint of resolution under ideal conditions but from the UK a telescope of at least 250 mm aperture is needed to show any resolution. M19 is one of the more flattened of the globular clusters and its elongated shape is visible even in small telescopes. It has a diameter of approximately 40 light years.

M20
RA: 18h 02.6m,  dec: -23° 02'.

Constellation: Sagittarius.

M20 lies 2° S and 2.5° W of μ Sagittarii. (It lies 50' to the SW of M21.)

Diameter: 28'.

Magnitude: 8.0.

Distance: 2300 ly.

Object: gaseous nebula.

M20 is known as the Trifid Nebula. It is a typical gaseous nebula, a large mass of glowing gas excited to emit radiation by a number of hot stars within it. Dark obscuring matter gives the appearance of divisions in the nebula. The diameter of the nebula is 30 light years. It is not conspicuous from UK latitudes.

M21
RA: 18h 04.6m,  dec: -22° 30'.

Constellation: Sagittarius.

M21 lies approximately 2.5° SW of μ Sagittarii.

Diameter: 13'.

Magnitude: 5.9.

Distance: 4250 ly.

Object: galactic cluster.

M21 contains some 60 stars. The brightest member of the cluster is of magnitude 8, but only 15 members are brighter than magnitude 12. M20 is amorphous. It is best viewed with a low power eyepiece.

M22
RA: 18h 36.4m,  dec: -23° 54'.

Constellation: Sagittarius.

M22 lies approximately 1.5° N and 2° E of λ Sagittarii.

Diameter: 24'.

Magnitude: 5.1.

Distance: 7800 ly.

Object: globular cluster.

M22 is large, bright and unmistakeable. It was the first globular cluster to be discovered (in 1665). It is one of the nearest globular clusters to Earth. The cluster is relatively loose, and a telescope of aperture 150 mm will resolve stars to the centre.

M23
RA: 17h 56.8m,  dec: -19° 01'.

Constellation: Sagittarius.

M23 lies 2.5° N and 3.5° W of μ Sagittarii.

Diameter: 27'.

Magnitude: 5.5.

Distance: 2150 ly.

Object: galactic cluster.

M23 is a fine, bright open cluster containing approximately 150 stars. The five brightest stars are magnitude circa 9.5.

M24
RA: 18h 16.9m,  dec: -18° 29'.

Constellation: Sagittarius.

M24 is approximately two-thirds of the way from γ Scuti to μ Sagittarii.

Diameter: 1.5°.

Magnitude: 4.0.

Distance: 16,000 ly.

Object: Milky Way star cloud.

M24 is a detached portion of the Milky Way. It was discovered by Messier in 1764 - he described it as a large nebulosity in which there are many stars of different magnitudes. From southerly latitudes, M24 is visible to the naked eye on a clear night. Binoculars provide a fine view.

The galactic cluster NGC6603 is embedded within the star field of M24.

M25
RA: 18h 31.6m,  dec: -19° 15'.

Constellation: Sagittarius.

M25 lies 2° N and 4° E of μ Sagittarii.

Diameter: 32'.

Magnitude: 4.6.

Distance: 2060 ly.

Object: galactic cluster.

M25 is a fine, open cluster. The five brightest stars are magnitude circa 8.5. There is a bright, slightly yellow star near the centre.

M26
RA: 18h 45.2m,  dec: -09° 24'.

Constellation: Scutum.

M26 lies about 1° ESE of δ Scuti - it can be easily located with 10x50 binoculars.

Diameter: 15'.

Magnitude: 8.0.

Distance: 4900 ly.

Object: galactic cluster.

M26 does not compare with M11 (also in Scutum) but it is still a fine cluster worth searching out. It is a small, compact group of approximately 100 stars, most lying inside a 9' diameter circle. The brightest star is of magnitude 11 and is situated on the SW edge of the cluster. In large telescopes, some 90-100 cluster members are visible brighter than magnitude 15. In a 150 mm telescope, about 25 members of the cluster can be seen (alongside some field stars).

M27
RA: 19h 59.6m,  dec: +22° 43'.

Constellation: Vulpecula.

M27 can be found with good binoculars. It lies 3° N of γ Sagittae and, once identified, is unmistakable.

Size: 8'x4'.

Magnitude: 8.0.

Distance: 975 ly.

Object: planetary nebula.

M27, known as the Dumb-bell Nebula, is one of the finest planetary nebulae and is a splendid object on a dark, clear night. It is best observed with a low magnification eyepiece. Binoculars show it as a roundish, pale disk. A 75 mm telescope begins to reveal an elliptical shape, giving a hint of the reason for the name. A 150 mm telescope reveals the elongated dumb-bell shape. A 250 mm telescope reveals a large (8'x4') faint, elongated object with the dumb-bell shape clearly visible as two brighter regions on either side of a slightly darker central region. A large telescope will also reveal faint nebulosity on either side of the dumb-bell shape showing an overall circular appearance.

As with all planetary nebulae, the expanding gas cloud that forms the visible nebula is illuminated by an extremely hot central star. The central star of M27 has a temperature of 85,000 K and an apparent magnitude of 13.5: it is invisible in all but the largest telescopes because of the surrounding nebulosity. M27 has a diameter of approximately 2.5 light years.

M28
RA: 18h 24.5m,  dec: -24° 52'.

Constellation: Sagittarius.

M28 lies approximately 1° NW of λ Sagittarii.

Diameter: 11'.

Magnitude: 6.8.

Distance: 19,000 ly.

Object: globular cluster.

M28 is a compact cluster, with bright centre, fading rapidly to the edge. A large aperture is required to resolve stars in M28.

M29
RA: 20h 23.9m,  dec: +38° 32'.

Constellation: Cygnus.

M29 lies in a particularly rich part of the Milky Way and therefore can be easily overlooked when searching with a telescope. The cluster lies about 1.7° SSE of γ Cygni (the central star in the Northern Cross) and is most easily found with binoculars. Once identified against the stellar background it can be readily found in a small telescope.

Diameter: 7'.

Magnitude: 6.6.

Distance: 4000 ly.

Object: galactic cluster.

M29 contains some 20 stars of which about 12 are in the magnitude range 8-9. They form a close-knit group of roughly trapezoidal shape somewhat resembling a miniature Pleiades. This part of the Milky Way contains a considerable amount of interstellar dust and the cluster itself appears to contain dust at a density approximately 1000 times greater than the average within the galaxy. The dust lying between the cluster and the Solar System is estimated to give a reduction in apparent brightness of about three magnitudes; M29 would be a spectacular object if seen through "clear" space!

M30
RA: 21h 40.4m,  dec: -23° 11'.

Constellation: Capricornus.

M30 lies approximately 0.75° S and 3° E of ζ Capricorni.

Diameter: 11'.

Magnitude: 7.2.

Distance: 41,000 ly.

Object: globular cluster.

M30 is relatively small, with a bright nucleus surrounded by a glowing area, outside of which are some faint individual stars.

M31
RA: 0h 42.7m,  dec: +41° 16'.

Constellation: Andromeda.

M31 is visible to the naked eye on a clear night approximately 1° W and slightly N of the magnitude 4.5 star ν Andromedae.

Size: 178'x63'.

Magnitude: 3.5.

Distance: 2.2 million ly.

Object: spiral galaxy.

M31, the Andromeda Galaxy, is the closest spiral galaxy. It is similar to the Milky Way in structure but 50% larger. It is approximately 180,000 light years in diameter and is surrounded by several smaller companion galaxies (including M32 and M110) and at least 300 globular clusters. It requires a low power and a dark sky to be seen to best effect. Large aperture instruments give the best views.

M32
RA: 0h 42.7m,  dec: +40° 52'.

Constellation: Andromeda.

M32 is a companion of M31, lying approximately 25' S of the centre of the parent galaxy.

Size: 8'x6'.

Magnitude: 8.2.

Distance: 2.22 million ly.

Object: dwarf elliptical galaxy.

M32 appears as a typical elliptical galaxy, but no detail is visible in typical amateur instruments.

M33
RA: 1h 33.9m,  dec: +30° 39'.

Constellation: Triangulum.

M33 is located on a line between α Trianguli and β Andromedae, about one third of the distance from the former.

Size: 62'x39'.

Magnitude: 5.7.

Distance: 2.35 million ly.

Object: spiral galaxy.

M33 is a face-on spiral galaxy sometimes known as the Pin Wheel Galaxy. It is a member of the Local Group of galaxies and is, in fact, the most distant known member of the group. It is the second closest spiral galaxy to us after the Andromeda Nebula, M31.

M33 is not an easy object for small telescopes because of its large size and low surface brightness. It is reportedly visible with the unaided eye under ideal conditions, making it the most distant object visible without optical aid. However such observations require excellent seeing and very dark skies not usually found from UK observing sites. It is, however, easily found with binoculars. When observing with telescopes, low powers are essential, for example only about 20x is all that should be used with a 75 mm aperture and no more than 50x with a 200 mm.

M34
RA: 2h 42.0m,  dec: +42° 47'.

Constellation: Perseus.

M34 is located just north of a line between the stars Algol and γ Andromedae, approximately 5° WNW of Algol. It is easy to find using binoculars, scanning WNW from Algol, and is a naked eye object in clear, dark skies.

Diameter: 35'.

Magnitude: 5.2.

Distance: 1450 ly.

Object: galactic cluster.

M34 is a bright, loose, open cluster, not as spectacular as the Sword Handle in Perseus but worth looking for. It contains about 80 stars in the magnitude range 8 to 13. There is a bright central knot of stars lying within a diameter of 9', which is visually the most impressive region of the cluster and can be resolved with binoculars. The outlying members of the cluster take its total diameter to 35'. Because M34 has a relatively large size, it is best viewed with binoculars or a rich‑field telescope. When observing with telescopes, low magnifications are preferable.

Messier discovered the cluster in August 1764; he described it as a cluster of small stars.

M35
RA: 6h 08.9m,   dec: +24° 20'.

Constellation: Gemini.

M35 is located 1° N and 1° E of the magnitude 4 star 1 Geminorum. It is visible without optical aid on dark nights.

Diameter: 28'.

Magnitude: 5.1.

Distance: 2850 ly.

Object: galactic cluster.

In 10x50 binoculars M35 appears as a misty patch with some resolution of its stars. A 75 mm telescope resolves the brighter members and begins to reveal some of the true beauty of the cluster. In a 250 mm telescope, M35 is a magnificent sight. Because of its size it requires low powers to be seen effectively. The cluster has a total luminosity of 2500 suns and contains at least 300 stars, of which more than 20 are in the magnitude range 8-9.

M36
RA: 5h 36.1m,  dec: +34° 08'.

Constellation: Auriga.

To find M36 move 3° S and 5° W of the magnitude 2 star θ Aurigae. M36 can then easily be located with binoculars.

Diameter: 12'.

Magnitude: 6.0.

Distance: 3700 ly.

Object: galactic cluster.

M36 is a fine object with an angular diameter of about 20' containing a central knot of brighter stars approximately 10' in diameter. A telescope of at least 75 mm aperture is needed to resolve individual stars. M36 is visually the brightest of the three Messier objects in Auriga and is also intrinsically the brightest (with a total luminosity of about 5000 suns) and the smallest. It contains several bright stars easily resolvable in small telescopes and about 60 stars in the magnitude range 9 to 14. M36 contains no red giant stars, and all its brighter members are B-type giants, indicating a younger than average age.

M37
RA: 5h 52.4m,  dec: +32° 33'.

Constellation: Auriga.

Move 4.5° S and 1° W of the magnitude 2 star θ Auriga to find M37. The cluster can easily be located with binoculars.

Diameter: 24'.

Magnitude: 5.6.

Distance: 3600 ly.

Object: galactic cluster.

In binoculars, M37 appears larger and more diffuse than M36. It requires a telescope of aperture 75 mm or greater to resolve individual stars. In a telescope, particularly with large aperture, it is undoubtedly the finest of the three Messier objects in Auriga. It contains about 500 stars, including a dozen red giants, 150 stars between magnitudes 10 and 12.5, and a bright red giant star of magnitude 9.5 near the centre. In a 250 mm telescope the central red giant shines out against the well-condensed background of the fainter stars of the cluster, the red colour being very prominent. The cluster has a luminosity of about 2500 suns.

M38
RA: 5h 28.7m,   dec: +35° 50'.

Constellation: Auriga.

M38 lies approximately 7° N of β Tauri. It can easily be located with binoculars.

Size: 21'.

Magnitude: 6.4.

Distance: 2750 ly.

Object: galactic cluster.

M38 is a large cluster, more scattered than M36 and M37, and requires low powers to be seen well. A telescope of at least 75 mm aperture is needed to resolve individual stars. M38 contains about 100 stars, the brightest of which is a yellow giant star of magnitude 7.9. The brighter members of the cluster are blue and yellow giant stars. M38 has a luminosity of around 1500 Suns making this cluster intrinsically the faintest of the three Messier objects in Auriga.

M39
RA: 21h 32.2m,  dec: +48° 26'.

Constellation: Cygnus.

M39 lies approximately 3° N of ρ Cygni, which in turn lies 9° E of Deneb (α Cygni). It lies in a particularly rich region of the Milky Way, is easily visible in binoculars and can be seen with the unaided eye.

Diameter: 32'.

Magnitude: 4.6.

Distance: 825 ly.

Object: galactic cluster.

M39 is a large, loose cluster. It contains approximately 30 stars forming a large, equilateral triangle. The brightest dozen or so stars form a triangular area about 0.5° across. M39 is best seen with a low power, wide field eyepiece. The cluster has a diameter of about 7 light years.

M40
RA: 12h 22.4m,  dec: +58° 05'.

Constellation: Ursa Major.

M40 lies approximately 1° N and 1° E of the magnitude 3 star Megrez (δ Ursa Majoris). The magnitude 5 star 70 Ursa Majoris lies roughly half way between M40 and Megrez.

M40 appears to be one of the few genuine mistakes in the Messier catalogue. At the co-ordinates given for this object lies a close double star (with components of magnitudes 9.6 and 10.1 at separation 49 arcsec) with no hint of nebulosity. It appears that Messier looked for a nebula in this position guided by the recorded observations of Hevelius in 1660 and found only the two faint stars. Although Messier himself did not observe any nebulosity he decided to include the object in his catalogue. There is a faint galaxy NGC4290 of magnitude 12.7 about 20' W of the pair of faint stars. However this is definitely not the object observed by Messier and is too faint to have been observed by Hevelius.
M41
RA: 6h 46.0m,  dec: -20° 44'.

Constellation: Canis Major.

M41 lies 4° S and 0.5° E of Sirius (α Canis Majoris). It has a magnitude 6 star, 12 Canis Majoris, on its SE edge. M41 is easily found with binoculars.

Diameter: 38'.

Magnitude: 4.5.

Distance: 1600 ly.

Object: galactic cluster.

M41 is a bright cluster, appearing as a fine object in small telescopes using low powers. It contains about 25 bright stars with a total of around 100 stars recognised as true cluster members in the magnitude range 7 to 13. From southerly latitudes, or on nights of exceptional clarity from northern latitudes, M41 is sufficiently bright to be visible without optical aid. Indeed it might well be the faintest object recorded by the ancient Greeks: it was mentioned by Aristotle around 350 BC as a mysterious cloudy spot in the sky. As is often the case with galactic clusters, there is a bright red star near the centre. This star is a red giant about 700 times the luminosity of the Sun.

M42
RA: 5h 35.4m,  dec: -05° 27'.

Constellation: Orion.

M42 surrounds θ Orionis, in the Sword of Orion. On a good clear night it is visible to the naked eye making θ Orionis appear slightly "fuzzy".

Size: 66'x60'.

Magnitude 4.0.

Distance: 1500 ly.

Object: gaseous emission nebula.

For amateur observers, M42 is the finest deep sky object in the heavens. In binoculars, it appears as a fuzzy patch surrounding θ Orionis. A 75 mm telescope will resolve θ Orionis into its four major components and show detail in M42. The surface brightness of M42 is so great that high magnification can be used with telescopes of apertures 200 mm or larger to reveal very intricate detail.

M42 is a vast cloud of glowing gas. Long exposure photographs reveal its diameter to be approximately 30 ly, with the bright central region some 2.5 light years in diameter. The density of the cloud is 10,000 gas molecules per cubic cm; by comparison, the Earth’s atmosphere at sea level is some 1,000 million million times more dense! Despite the extreme rarity of the gas in M42, there is enough material to form 10,000 stars the size of the Sun. The gas in M42 is mostly Hydrogen at a temperature 10-50 K. Ionising ultraviolet radiation emitted by the stars of θ Orionis illuminates the gas cloud and causes it to glow. New stars are forming in M42 as gravity causes material to accrete around centres of condensation.

M43
RA: 5h 35.6m,  dec: -05° 16'.

Constellation: Orion.

M43 surrounds θ Orionis, in the Sword of Orion.

Size: 20'x15'.

Magnitude: 9.0.

Distance: 1500 ly.

Object: gaseous emission nebula.

M43 is part of the same gaseous nebula as M42, but appears detached by a region of dark nebulosity. It is illuminated by an 8th magnitude star, located centrally.

M44
RA: 8h 40.1m,  dec: +19° 59'.

Constellation: Cancer.

M44 lies roughly half way between Regulus and Pollux. The two 4th magnitude stars γ and δ Cancri lie slightly to the NE and SE of M44 respectively.

Diameter: 95'.

Magnitude: 3.1.

Distance: 600 ly.

Object: galactic cluster.

M44 is a star cluster which is well known as Praesepe or the Beehive. It is easily visible to the naked eye as a faint misty path of magnitude 4.5, the individual stars being just too faint to be resolved without optical aid. The diameter of the brighter central region of the cluster is over 1° and it is an excellent object for binoculars or rich field telescopes. In other telescopes, low power, wide field eyepieces are required if the cluster is to be seen in its entirety.

M44 contains at least 200 stars lying in the magnitude range 6.3 to 17. About 100 of the stars are brighter than magnitude 10.9 which would be the apparent magnitude of the Sun if it were placed within the cluster! Eleven of the stars are sixth magnitude and Galileo, first to observe it with a telescope, counted 36 stars. The brightest star is about 70 times the luminosity of the Sun. The cluster is one of the closer galactic clusters. The brighter central region of M44 has a diameter of approximately 10 light years while some of the fainter outlying members are as much as 20 light years from the centre.

M45
RA: 3h 47.0m,  dec: +24° 07'.

Constellation: Taurus.

Easily visible to the naked eye.

Diameter: 110'.

Magnitude: 1.2.

Distance: 410 ly.

Object: galactic cluster.

M45 is the familiar Pleiades or Seven Sisters, known from ancient times. It provides a good test of both eyesight and seeing conditions. There are potentially 20 stars within the Pleiades of naked eye visibility, but the fainter stars are drowned out by the light of the brightest six. Most people can easily see the following six stars:

Careful observation with the naked eye usually shows the star 27 Tau and 28 Tau to be indeed two individual stars making up the famous seven. Keener eyed people will find the stars 16 Tau = Calaeno and 21 Tau and 22 Tau = Asterope (two components taken as one star) bringing their total to nine stars. Observers with even keener eyesight can separate the stars 21 Tau and 22 Tau (2.9' apart and of almost equal magnitude) to bring the total to 10 naked eye stars.

Some famous observers recorded the following counts of naked eye stars visible in the Pleiades:

A word of warning about counts of naked eye stars visible in the Pleiades... It is very easy to convince oneself that it is possible to see the more difficult stars of the Pleiades if observing both with the naked eye and binoculars (or a low power telescope). A more rigorous technique is to first observe with the eye alone noting all the stars visible and drawing them in their relative positions. Having satisfied oneself that no further stars are visible, use binoculars or a telescope with low power, wide angle eyepiece to confirm the stars in the positions drawn.

The Pleiades cluster lies about 410 light years distant with a diameter of about 20 light years. The brightest stars in the cluster are all blue giant type stars. For comparison, the Sun at the distance of the Pleiades would be a 10th magnitude object! An interesting feature of the cluster is the faint nebulosity that becomes prominent in long-exposure photographs. It appears to be caused by dust, and possibly larger solid particles, enveloping the entire cluster and shining by reflecting starlight. The brightest portion of nebulosity surrounds the star Merope (23 Tau) and is known as the Merope Nebula. Professor H Tempel discovered the Merope Nebula with a 100 mm refractor in Venice on 19 October 1859. It is, however, a very difficult object and cannot be seen with the Tomline Refractor because of light pollution. I (David Payne) have only seen the object clearly and unmistakably with my 250 mm reflector once, on an exceptional night in December 1985 when I could also see Halley's Comet with the unaided eye!

M46
RA: 7h 41.8m,  dec: -14° 49'.

Constellation: Puppis.

M46 is 2.5° N and 14° E of Sirius and 1.5° E of M47.

Diameter: 27'.

Magnitude: 6.1.

Distance: 3200 ly.

Object: galactic cluster.

M46 is a lovely star cluster! It is easily seen in binoculars as a circular misty patch of light about 30' in diameter, and a small telescope will resolve many stars within it. In a 250 mm telescope with low power eyepiece the cluster is magnificent with dozens of stars resolved. The cluster contains about 150 identifiable members in the magnitude range 10 to 13. It is fainter than M47 but is more impressive, particularly in large telescopes. M46 has a diameter of 30 light years.

An unique feature of M46 is the presence of a small planetary nebula, NGC2438, lying approximately 7' N of the centre, apparently inside the borders of the cluster. However, radial velocity measurements have demonstrated that the planetary nebula is a foreground object and not a true member of the cluster. NGC2438 can be seen in small telescopes but is at its best against the background of M46 in telescopes of 200 mm or greater aperture.

M47
RA: 7h 36.6m,  dec: -14° 30'.

Constellation: Puppis.

M47 is 2° N and 12° E of Sirius, due south of Procyon and 1.5° W of M46.

Diameter: 30'.

Magnitude: 4.4.

Distance: 1750 ly.

Object: galactic cluster.

M47 is a bright, loose cluster situated close to M46. It contains fewer stars but is brighter than M46 and is a splendid object in small telescopes. On good dark nights it can be seen without optical aid. However the majority of its members are faint stars and so a telescope of at least 250 mm aperture is needed to appreciate the true beauty of the object. About 45 stars have been identified as true cluster members, the brightest of which, a blue giant, is magnitude 5.7. Near the centre of M47 is an easy double star with components of magnitude 7.8 and 7.9 at a separation of 7.5 arcsec.

M48
RA: 8h 13.8m,  dec: -05° 48'.

Constellation: Hydra.

M48 can be found as follows. Extend a line from β Canis Minoris through Procyon (α Canis Minoris) by three times the distance from the former to the latter to locate the group of three close-in-line stars 1, 2 and c Hydrae. M48 lies 3° W and 2° S of this group.

Diameter: 54'.

Magnitude: 5.8.

Distance: 1500 ly.

Object: galactic cluster.

M48 is a bright galactic cluster. It was originally one of Messier's missing objects: when he catalogued it he gave its position 4° north of NGC2548 where no such object exists! (NGC2548 itself was identified as the object to which Messier referred from its similarity with the description that he provided.)

M48 can easily be found in binoculars, where it appears as a faint misty patch with a hint of resolution. In a 75 mm telescope it appears as a triangle of stars with two curved chains of stars in the centre. In a 250 mm telescope the cluster is fully resolved revealing many more stars lying outside the triangular region. The brightest star is magnitude 8.8 and lies near the centre of the cluster. M48 contains about 50 stars in total down to magnitude 13. Low power, wide field eyepieces are best for observing M48. The cluster is estimated to have a diameter of about 20 light years.

M49
RA: 12h 29.8m,  dec: +08° 00'.

Constellation: Virgo.

M49 lies 4° S of the main Virgo cluster.

Size: 9'x7'.

Magnitude: 8.4.

Distance: 41 million ly.

Object: giant elliptical galaxy.

M49 is a giant elliptical galaxy similar in size to M60. It has a mass of approximately 1000 billion solar masses. It appears as a round, glowing patch with a distinctly brighter central area.

M50
RA: 7h 02.8m,  dec: -08° 23'.

Constellation: Monoceros.

M50 lies about a third of the way along the line from Sirius to β Canis Minoris.

Size: 16'.

Magnitude: 5.9.

Distance: 2950 ly.

Object: galactic cluster.

M50 is rich and compressed with about 200 or so stars in the magnitude range 9 to 14 distributed in an oval shape 15'x25' in extent. The main core of about 100 stars occupies a diameter of about 10'. A small telescope will resolve the brighter members of the cluster while a larger aperture shows a multitude of fainter stars. M50 has a diameter of approximately 15 to 20 light years.

There is a fairly prominent red star just south of the centre of the cluster. (It is common to have a red star near the centre of a galactic cluster.) The integrated magnitude of the cluster is 6.3 making it a potential naked eye object for keen sighted observers under good clear conditions and dark skies.

M51
RA: 13h 29.9m,  dec: +47° 12'.

Constellation: Canes Venatici.

M51 can be found below the "handle" of Ursa Major. It lies approximately 3.5° from η Ursae Majoris (the star at the end of the tail of the Great Bear). The line from η to M51 makes a right angle with the line from η to ζ Ursae Majoris (Mizar).

Size: 11'x8'.

Magnitude: 8.1.

Distance: 37 million ly.

Object: spiral galaxy.

On the northern edge of Canes Venatici, M51 is visible in binoculars as a faint, small, misty spot. It is a face-on spiral galaxy discovered by Messier in 1773. It was the first galaxy found to have a spiral structure (discovered by the Earl of Rosse with his 1.8 m aperture reflector at Birr Castle, Ireland in 1845). A striking feature of M51 is the presence of a bright irregular companion galaxy which appears to hang on the end of one of the spiral arms of the main galaxy. M51 is known as the Whirlpool Galaxy.

A 75 mm telescope will show the nuclei of both the main and companion galaxies under good dark sky conditions. Larger instruments will reveal a faint glow surrounding the main galaxy. The spiral structure can be glimpsed with a 200 mm telescope under the best conditions. A 250 mm or larger instrument will show the spiral structure including the arm linking the main galaxy to the companion.

The mass of M51 is estimated to be about 160 billion Suns and its diameter approximately 100,000 light years.

M52
RA: 23h 24.2m,  dec: +61° 35'.

Constellation: Cassiopeia.

M52 can be found about 5° W of β Cassiopeiae, approximately 1° S of the star 4 Cassiopeiae.

Size: 13'.

Magnitude: 6.9.

Distance: 3000 ly (uncertain).

Object: galactic cluster.

M52 is a fine, moderately rich cluster containing around 200 stars, with magnitudes in the range 9 to 15, in a region of diameter 12'. It is a fine object for small telescopes. A 75 mm instrument will easily resolve the many brighter stars in the cluster and larger instruments will bring out the fainter background stars. M52 is one of the more condensed galactic clusters and is thought to be relatively young.

M53
RA: 13h 12.9m,  dec: +18° 10'.

Constellation: Coma Berenices.

M53 is easily found 1° NE of the magnitude 4 star α Comae.

Diameter: 13'.

Magnitude: 7.6.

Distance: 69,000 ly.

Object: globular cluster.

M53 appears visually as an 8th magnitude circular patch of light about 10' in diameter. It has a pronounced central nucleus and the luminosity fades at the edges. A telescope of 100 mm aperture provides some resolution of individual stars. A telescope of 250 mm aperture resolves stars at the edges of the cluster and also some against the misty background of the bright nucleus. M53 has a diameter of about 60 light years and a luminosity of about 200,000 Suns.

Lying 1° SE of M53 is the cluster NGC5053. This has an integrated magnitude of 10.5 spread over a disk 8' in diameter. The low surface brightness means that a telescope of at least 200 mm aperture is needed to detect the object visually.

M54
RA: 18h 55.1m,  dec: -30° 29'.

Constellation: Sagittarius.

M54 is very easy to find, lying 0.5° S and 1.5° W of ζ Sagittarii. However, it lies too far south to be easily visible from UK latitudes.

Diameter: 9'.

Magnitude: 7.6.

Distance: 49,000 ly.

Object: globular cluster.

M54 is a bright, globular cluster. It has a diameter of about 6' with a condensed centre about 2' in diameter. It is about 55 light years in diameter. Binoculars show M54 only as a stellar point, and a telescope is necessary to reveal the disk of the cluster.

M55
RA: 19h 40.0m,  dec: -30° 58'.

Constellation: Sagittarius.

M55 lies 1° S and 7° E of ζ Sagittarii. However, it is too diffuse and lies too far S to be easily visible from UK latitudes.

Diameter: 19'.

Magnitude: 7.0.

Distance: 20,000 ly.

Object: globular cluster.

M55 is almost impossible to observe from UK latitudes except under exceptionally clear and dark conditions.

M56
RA: 19h 16.6m,  dec: +30° 11'.

Constellation: Lyra.

M56 is located about a third of the way along a line from the lovely coloured double star β Cygni to γ Lyrae. It can be found with binoculars but the task is more easily accomplished using a telescope.

Diameter: 7'.

Magnitude: 8.3.

Distance: 45,600 ly (uncertain).

Object: globular cluster.

M56 is a compact cluster about 5' in apparent diameter with the brighter portion lying in an area of diameter 4'. In a small telescope, the brighter central region appears uniformly bright without any marked central condensation; however in larger telescopes it is seen to be slightly irregular. A 150 mm telescope is required to resolve the outer edges of the cluster although a 100 mm telescope will provide a hint of resolution.

M56 is estimated to have a diameter of about 65 light years. Its total luminosity is about 90,000 suns.

M57
RA: 18h 53.6m,  dec: +33° 02'.

Constellation: Lyra.

M57 lies about 7° SE from Vega (α Lyrae) and is situated almost midway between the two stars β and γ Lyrae. It is visible in binoculars but is not distinguishable from the faint background stars. However, it is easy to find with a telescope using a low power of about 50x; such a magnification will reveal the disk shape and will also give a reasonable field of view for finding the object.

Size: 80"x60".

Magnitude: 9.0.

Distance: 1410 ly.

Object: planetary nebula.

M57 is the most famous of all planetary nebulae: it is the glorious Ring Nebula in Lyra. In a small telescope the nebula shines as a pale disk of light with the ring structure difficult to discern. A 75 mm telescope will show a ghostly glowing ellipsoid. A 150 mm telescope will clearly show the ring structure and will reveal its elliptical shape. Apertures of 250 mm and above will reveal nebulosity inside the ring and the structure in the ring itself including the fading at the edges of the major axis. The relatively high surface brightness of the ring allows high magnifications to be used with large aperture instruments. There is a magnitude 15 star at the centre of the ring which requires an aperture of at least 450 mm to be seen visually.

Early observers thought that the ring consisted of unresolved stars; indeed some early reports even record resolution into stars under good conditions! It is now known that the ring is a shell of gas expelled by the central star and glowing by flourescence, being bathed in intense ultraviolet radiation emitted by the central star (which has a temperature of approximately 100,000 K). The ring shape is observed simply because a greater amount of the glowing gas is seen when looking through the edge of the shell than when looking towards the centre of the nebula.

The distances of planetary nebulae are always uncertain since they are too far away to be measured by parallax methods and their intrinsic brightness can only be determined from theoretical calculations based on the physics of the fluorescence process. The estimated distance of M57 is around 1410 light years which would give it a true diameter of about 0.5 light years.

Spectroscopic analysis shows the gases in the Ring Nebula to be expanding at about 20 km/sec. This implies that the nebula would expand by 1.7 arcsec in 60 years; however, measurements made from photographic plates taken 60 years apart show that the increase in apparent size is no more than 0.3 arcsec. It is therefore likely that the visible, glowing region of gas observed is not the true diameter of the nebula but only that region relatively close to the central star with a sufficiently high density to produce visible fluorescence when subject to UV radiation.

M58
RA: 12h 37.7m,  dec: +11° 49'.

Constellation: Virgo.

M58 is the brightest of the galaxies in the Virgo group and is easy to find. It is located 1° W and slightly N of M59.

Size: 5'x4'.

Magnitude: 9.8.

Distance: 41 million ly.

Object: barred spiral galaxy.

M58 is a bright, compact, barred spiral galaxy. It is easily visible and the barred structure can just be discerned in a 200 mm telescope under good conditions. M58 has a mass of approximately 160 billion solar masses, similar to that of the Milky Way galaxy.

M59
RA: 12h 42.0m,  dec: +11° 39'.

Constellation: Virgo.

M59 lies approximately 1.5° N of ρ Virginis. M59 and M60 should appear together in the same low power field, lying nearly E-W.

Size: 5'x3'.

Magnitude: 9.8.

Distance: 41 million ly.

Object: elliptical galaxy.

M59 is small, at only about 24,000 light years diameter, but has a mass of 250 billion suns. It appears as a small oval patch with a slightly brighter nucleus.

M60
RA: 12h 43.7m,  dec: +11° 33'.

Constellation: Virgo.

See instructions above for finding M59.

Size: 7'x6'.

Magnitude: 8.8.

Distance: 41 million ly.

Object: giant elliptical galaxy.

M60 is among the largest elliptical galaxies known with a mass around 1000 billion suns. In a low power field it is possible to observe M59 and M60 together. M60 is noticeably brighter than M59 and is almost as bright as M58 (the brightest galaxy in the Virgo group). M60 is almost perfectly circular in outline and has a bright central nucleus. The faint spiral galaxy NGC 4647, of magnitude 11.5, lies 2.5' to the NW of M60.

M61
RA: 12h 21.9m,  dec: +04° 28'.

Constellation: Virgo.

M61 lies 8° S of the main Virgo cluster.

Size: 6'x5'.

Magnitude: 9.7.

Distance: 41 million ly.

Object: spiral galaxy.

M61 is a spiral galaxy with a mass of about 50 billion suns, about one quarter the mass of the Milky Way galaxy. It appears as a faint blur, with a poorly-defined edge and little evidence of a central condensation.

M62
RA: 17h 01.2m,  dec: -30° 07'.

Constellation: Ophiuchus.

M62 only ever rises some 8° above the horizon from Suffolk and, from Orwell Park Observatory, the lights of Felixstowe Docks obscure the object! However, observers in East Anglia with a good southern horizon should be able to locate it. M62 lies on the border of Ophiuchus and Scorpius and different sources list it as belonging to one constellation or the other.

Diameter: 14'.

Magnitude: 6.5.

Distance: 22,500 ly.

Object: globular cluster.

A 250 mm telescope will provide some resolution of stars in M62, but from UK latitudes the low altitude of the cluster means that exceptional skies are necessary to achieve this.

M62 is one of the most irregularly shaped globular clusters, and this may be related to its being embedded within the galactic hub in proximity to the galactic centre. The brightest condensation within M62 has a diameter of approximately 1.5' and lies to the SE of the centre making the object look particularly comet-like! M62 has a diameter of approximately 40 light years.

M63
RA: 13h 15.8m,  dec: +42° 02'.

Constellation: Canes Venatici.

M63 can easily be located using binoculars, lying near the centre of the constellation on a line between the star at the end of the tail of Ursa Major (η Ursae Majoris) and α Canum Venaticorum.

Size: 12'x8'.

Magnitude: 8.6.

Distance: 23.8 million ly.

Object: spiral galaxy.

Faint stars on either side of M63 confuse the image in binoculars, giving the impression that the galaxy is larger and more conspicuous than it really is. A 75 mm telescope clearly separates the galaxy from the nearby stars revealing the fainter nucleus. A 250 mm aperture shows the nucleus as small and bright with a surrounding rather featureless fainter region.

M63 is estimated to have a diameter of about 90,000 light years and a total mass of about 115 billion solar masses.

M64
RA: 12h 56.7m,  dec: +21° 41'.

Constellation: Coma Berenices.

M64 lies 1° ENE of the magnitude 5 star 35 Comae.

Size: 9'x5'.

Magnitude: 8.5.

Distance: 12 million ly.

Object: spiral galaxy.

M64 is a large, highly luminous spiral galaxy with very smooth and uniform spiral arms - in typical amateur instruments it appears visually as an ellipse. Its most remarkable feature is a huge cloud of obscuring dust bordering the north east side of the nucleus: this appears black against the background of the galaxy and gives the object its name, the Black Eye Galaxy. The dust cloud is visible in a 150-200 mm telescope under good conditions and is clearly visible in a 250 mm telescope, although a high magnification (e.g. 200x) may be necessary to darken the background sky.

Although M64 is situated in the direction of the Virgo Cluster of galaxies, it is not a member of the Cluster and in fact lies much closer to the Earth.

M65
RA: 11h 18.9m,  dec: +13° 05'.

Constellation: Leo.

M65 and M66 lie half way between the stars θ and ι Leonis (magnitudes 3 and 4 respectively). M65 and M66 lie approximately half a degree apart and are visible together in a low power eyepiece. M65 is slightly S of E of M66.

Size: 10'x3'.

Magnitude: 9.3.

Distance: 29 million ly.

Object: spiral galaxy.

M65 and M66 together form the showpiece galaxies in Leo. M65 is actually a member of a triple group of galaxies, together with M66 and NGC3628 (mag 9.5). Both M65 and M66 are bright and distinct with clearly defined central nuclei. It is possible to use high magnifications on M65 and M66 to bring out detail of their structure.

On long exposure photographs, M65 shows a radius of up to 200 arcsec. There is evidence of interaction to the E between M65 and M66. M65 is estimated to have a mass of some 200 million suns. The central nucleus of the galaxy has a dust arm emerging from it. M65 has a diameter of 50,000 light years.

M66
RA: 11h 20.2m,  dec: +12° 59'.

Constellation: Leo.

See entry above for M65 for details of locating M66.

Size: 9'x4'.

Magnitude: 9.0.

Distance: 29 million ly.

Object: spiral galaxy.

See entry for M65 above. M66 is significantly larger than M65 but has only approximately half the mass. It is brighter than M65 but the latter tends to be more conspicuous due to its more sharply defined outline.

M66 has a large concentration at the end of its S arm. It has thick and asymmetric spiral arms to the N. It has a diameter of 60,000 light years.

M67
RA: 08h 51.4m,  dec: +11° 49'.

Constellation: Cancer.

M67 lies in Cancer and is easily found about 1.8° W of α Cancri.

Diameter: 30'.

Magnitude: 6.9.

Distance: 2700 ly.

Object: galactic cluster.

M67 is an unusual and very rich galactic cluster. It contains at least 500 stars within a diameter of about 12 light years. Stars in M67 range from the brightest at magnitude 10 to the faintest at magnitude 17. M67 is very different to M44, the other Messier object in Cancer: M67 is 2.5 magnitudes fainter and is invisible to the naked eye.

M67 can be seen in binoculars as a faint misty patch. A 75 mm telescope will resolve the brighter members against the misty background and will show the cluster as elongated or slightly triangular in shape. In a 250 mm telescope the cluster is clearly resolved with 50 or more of the brighter members shining against a profusion of fainter background stars.

The colour/magnitude distribution of the stars comprising M67, when plotted on a Hertzsprung-Russell diagram, resembles the distribution of a globular cluster rather than a galactic cluster. This is an indication of great age and it is estimated that M67 is about 10  billion years old, in fact, the oldest of all galactic clusters. Most galactic clusters orbit the galaxy close to its central plane, where gravitational interactions are most intense. In fact, gravitational interactions tend to disrupt most galactic clusters as they orbit the galaxy, and it is very unusual for a galactic cluster to survive in such a compact form as M67 for so long. M67 appears to have survived because the inclination of its orbit takes it well outside the plane of the galaxy for most of its orbit.

M68
RA: 12h 39.5m,  dec: -26° 45'.

Constellation: Hydra.

To locate M68, first find β Corvi, then a magnitude 5.5 star 3° to the SSE. M68 is then 45' to the NE.

Diameter: 12'.

Magnitude: 8.2.

Distance: 36,000 ly.

Object: globular cluster.

Because of its southerly declination, M68 is difficult to observe from UK latitudes. It appears as a round disk, which is easily resolved. It is approximately 42 light years in diameter.

M69
RA: 18h 31.4m,  dec: -32° 21'.

Constellation: Sagittarius.

M69 is located 2.5° S and 2° E of δ Sagittarii. Because of its southern declination it is very difficult to find from UK latitudes.

Diameter: 7'.

Magnitude: 7.6.

Distance: 23,500 ly.

Object: globular cluster.

M69 is a small but relatively bright globular cluster. It exhibits a soft, even glow and does not show a central condensation in a small telescope. It requires a high magnification to resolve individual stars.

M70
RA: 18h 43.2m,  dec: -32° 18'.

Constellation: Sagittarius.

M70 is located 2.5° S and 4° W of ζ Sagittarii. Like M69, the very southern declination of M70 makes it difficult to find from UK latitudes.

Diameter: 8'.

Magnitude: 8.1.

Distance: 65,000 ly.

Object: globular cluster.

Although M70 is fainter than the nearby M69, it has a bright central region which makes it more prominent. M70 has a diameter of about 60 light years.

M71
RA: 19h 53.8m,  dec: +18° 47'.

Constellation: Sagitta.

M71 lies approximately half way between γ and δ Sagittae.

Diameter: 7'.

Magnitude: 8.2.

Distance: 13,000 ly.

Object: globular cluster.

A small telescope shows M71 as a slightly triangular, misty patch, but an instrument of 150 mm or greater aperture begins to resolve it as a beautiful, rich cluster. It has a diameter of about 30 light years although suspected cluster members have been found at a distance four times as great. There was dispute about the status of M71 as a globular cluster: it is very open without the condensed nucleus usually associated with a globular cluster and the spectrum of its starlight is not typical of a globular cluster. However, its spectrum is closer to that of a typical globular cluster than to that of a typical galactic cluster, so M71 is now generally classified as a globular.

M72
RA: 20h 53.5m,  dec: -12° 32'.

Constellation: Aquarius.

M72 lies 3° S and 1.5° E of η Aquarii. There is a magnitude 6 star some 40' W of the cluster.

Diameter: 6'.

Magnitude: 9.3.

Distance: 62,000 ly.

Object: globular cluster.

M72 is an open globular cluster. It appears pale and of uniform brightness. A telescope of aperture greater than 250 mm is needed to provide any resolution.

M73
RA: 20h 58.9m,  dec: -12° 38'.

Constellation: Aquarius.

M73 lies 1.5° E and slightly S of M72.

M73 is an asterism of four stars in Aquarius. Messier discovered it on 04 October 1780 writing: A cluster of three or four small stars which looks like a nebula at first sight; it contains a little nebulosity: it is on the same parallel as the preceding nebula (M72). The magnitudes of the stars are: 10.5, 10.5, 11.0 and 12.0 giving an integrated magnitude of approximately 9.
M74
RA: 1h 36.7m,  dec: +15° 47'.

Constellation: Pisces.

M74 lies about 1° SW of the pair of 6th magnitude stars 103 and 105 Piscium. It can be a difficult object unless the sky is very dark and seeing conditions are good.

Size: 10'x9'.

Magnitude: 9.2.

Distance: 26 million ly.

Object: spiral galaxy.

M74 in Pisces is a large, faint face-on spiral galaxy which requires low powers and good dark skies. It has a condensed nucleus which is visible in small telescopes.

M75
RA: 20h 06.1m,  dec: -21d 55'.

Constellation: Sagittarius.

M75 lies about 27° W and about 12° S of Scutum, on the border of Capricornus and Sagittarius. It is in a faint region of Sagittarius and is most easily found by star-hopping from β Capricornus, which lies about 8° to the NW.

Diameter: 6'.

Magnitude: 8.5.

Distance: 78,000 ly.

Object: globular cluster.

In all but the largest amateur telescopes, M75 is a compact, unresolved, fuzzy disk. The brightest stars in M75 are of magnitude 17, apart from five in the magnitude range 12.5-14 situated on the borders of the cluster. These five stars can give the illusion of partial resolution in small telescopes. M75 is one of the most distant globular cluster listed in Messier's catalogue. Its estimated luminosity is 160,000 Suns.

M76
RA: 1h 42.2m,  dec: +51° 34'.

Constellation: Perseus.

M76 is located 1° NNW of the magnitude 4 star φ Persei. It can be found with a small telescope.

Size: 157"x87".

Magnitude: 11.0.

Distance: 8,200 ly.

Object: planetary nebula.

M76 is often regarded as the most difficult of the Messier objects. It is a faint planetary nebula, sometimes called the Little Dumb-bell due to its obvious elongated shape and similarity to the Dumb-bell Nebula (M27 in Vulpecula). Although M76 can be found with a small telescope (as small as 75 mm aperture), it requires good seeing conditions to observe and a larger telescope is needed to discern detail of the irregular dumb-bell shape. With a 200 mm telescope it is possible to discern the elongated shape and also some of the irregular brightness that can make the nebula appear to be in two sections, with a darker region in the centre.

M76 is powered by a magnitude 16.5 central star. This star, which has a very high surface temperature of approximately 60,000 K (compared with 6000 K for the Sun), irradiates surrounding material with UV radiation, causing it to fluoresce.

M77
RA: 2h 42.7m,  dec: -00° 01'.

Constellation: Cetus.

M77 lies 15' S and 30' E of δ Ceti.

Size: 7'x6'.

Magnitude: 8.8.

Distance: 52 million ly.

Object: spiral galaxy.

M77 is a bright, compact, spiral galaxy. Together with the Sombrero Galaxy (M104), it was one of the first galaxies to show a large red shift, and thereby ushered in the concept of the expanding universe. It is visible in binoculars as a faint, hazy "star". A 75 mm telescope confirms this appearance. A 250 mm telescope shows the nucleus as a bright, almost stellar point with the spiral arms as a fainter halo surrounding the nucleus. The surface brightness of M77 allows the use of moderately high powers (up to 250x) which still show the nucleus as small and starlike.

M77 is a Seyfert galaxy, named after the American astronomer Carl Seyfert. A typical Seyfert galaxy is characterised by a small, bright nucleus with bright emission lines in its spectrum, acting as a powerful radio source. Seyfert galaxies appear to have undergone violent activity in their core regions; they also exhibit some of the characteristics of quasars.

M78
RA: 5h 46.7m,  dec: +00° 03'.

Constellation: Orion.

M78 lies 2.3° NE of ζ Orionis (the SE star in Orion's Belt).

Size: 8'x6'.

Magnitude: 8.0.

Distance: 1630 ly.

Object: gaseous reflection nebula.

M78 is a bright region often overlooked because of the magnificence of the nearby Great Nebula, M42. It is a bright portion of the same mass of nebulosity as M42 but lying several degrees away. M78 is one of the brightest reflection nebulae in the sky; however reflection nebulae tend to be very faint objects and even the "bright" ones can be difficult to observe! In a small telescope, M78 appears as two 10th magnitude stars surrounded by faint nebulosity. A 100 mm telescope will reveal the nebulosity on a good dark night but an instrument of 200-250 mm aperture is needed in order to reveal the elongated shape.

M79
RA: 5h 24.5m,  dec: -24° 33'.

Constellation: Lepus.

M79 is located on a line from α to β Leporus, extended SSW from the latter for approximately 4°.

Diameter: 9'.

Magnitude: 7.7.

Distance: 43,000 ly.

Object: globular cluster.

Although M79 is not one of the most brilliant globular clusters, it is worth searching for if skies are dark and clear and there is a good southern horizon. In small telescopes, it appears as a fuzzy circular patch. In telescopes of 200 mm or greater aperture it shows some resolution in its outer edges.

M80
RA: 16h 17.0m,  dec: -22° 59'.

Constellation: Scorpius.

M80 lies halfway between α Scorpii (Antares) and β Scorpii.

Diameter: 9'.

Magnitude: 7.3.

Distance: 36,000 ly.

Object: globular cluster.

M80 is a small cluster. It has a visual diameter of 5' with a central, brighter region some 3' in diameter. A 150 mm telescope will show some resolution in M80 under a clear, dark sky. However, from the latitude of East Anglia, a telescope of at least 250 mm aperture is required to achieve any resolution, even under relatively good conditions. The cluster has a diameter of about 50 light years.

M81
RA: 9h 55.6m,  dec: +69° 04'.

Constellation: Ursa Major.

Continue the line from γ to α Ursae Majoris to the NE for slightly further than the distance between them. M81 and M82 can be found together in the same low power field of view at the end of the line, approximately 30' from 24 Ursae Majoris.

Size: 26'x14'.

Magnitude: 6.8.

Distance: 8.5 million ly.

Object: spiral galaxy.

M81 and M82 are a fine pair of galaxies, only 38' apart, forming a striking pair in a low power, wide field eyepiece. Both objects can be seen with 10x50 binoculars as rather small, faint misty patches. In a 75 mm telescope M81 appears circular.

M81 is a classical spiral galaxy with well-defined arms surrounding a bright central mass of stars which in turn has a small, bright nucleus. The galaxy is about 36,000 light years in diameter, only ⅓ the diameter of our own galaxy, yet has a mass of around 250,000 million Suns, greater than the mass of the Milky Way. This makes M81 one of the densest galaxies known.

M82
RA: 9h 55.8m,  dec: +69° 41'.

Constellation: Ursa Major.

Located in close proximity to M81 (see above).

Size: 11'x5'.

Magnitude: 8.4.

Distance: 8.5 million ly.

Object: irregular galaxy.

M81 and M82 are a fine pair of galaxies, only 38' apart, forming a striking pair in a low power, wide field eyepiece. Both objects can be seen with 10x50 binoculars as rather small, faint misty patches. A 75 mm telescope is adequate to discern the elongated shape of M82. On a clear dark night, a 250 mm telescope will reveal some of the irregularity of the galaxy.

Compared with M81, M82 is more northerly, fainter and appears much more elongated. It is also smaller than M81; it has a total mass of about 50,000 million Suns in a diameter of about 16,000 light years. M82 is an unusual galaxy with no real spiral structure: in photographs taken with large telescopes it appears as an elongated glowing mass with dark spots and streaks presumably produced by dark obscuring material. The light from the galaxy is significantly polarised, particularly in the outer edges, suggesting a strong and extensive magnetic field. The galaxy is also a strong source of radio waves generated by energetic charged particles travelling through the magnetic fields.

It used to be thought that the peculiar features of M82 were caused by the collision of two galaxies but it is now known that the energy of the radio emissions is far too great to be explained by any collision process. Studies of M82 now suggest that there was a tremendous outburst some 1.5 million years ago involving the energy from several million stars. One possible explanation is that in the core of the galaxy, huge "hyper stars" formed from many thousands of "ordinary" stars and subsequently collapsed directly into black holes releasing enormous amounts of energy in the process. Although M82 is not visually one of the best objects for small telescopes, its exotic physics make it worth searching for!

M83
RA: 13h 37.0m,  dec: -29° 52'.

Constellation: Hydra.

From β Corvi move 10° E to the magnitude 3.5 star γ Hydrae, then move 6.5° S and 3.25°E. A star of magnitude 5.5 lies 40' to the NE of the galaxy.

Size: 11'x10'.

Magnitude: 8.0.

Distance: 8.5 million ly.

Object: spiral galaxy.

M83 is difficult to observe from UK latitudes. It appears as a hazy star.

M84
RA: 12h 25.1m,  dec: +12° 53'.

Constellation: Virgo.

M84 lies 20' W and slightly S of M86. It can be seen in the same low power field of view as M86.

Size: 5'x4'.

Magnitude: 9.3.

Distance: 41 million ly.

Object: galaxy.

M84 is a galaxy intermediate between spiral and elliptical forms. Visually, it appears circular.

M85
RA: 12h 25.4m,  dec: +18° 11'.

Constellation: Coma Berenices.

M85 lies 0.5° N and slightly over 1° E of the 5th magnitude star 11 Comae.

Size: 7'x5'.

Magnitude: 9.2.

Distance: 41 million ly.

Object: galaxy.

M85 is similar to M84 in all essential aspects. Visually M85 appears elliptical; however, photographs taken at the Mount Palomar Observatory show partial spiral arms and the galaxy is therefore classified as intermediate between spiral and elliptical forms. M85 is one of the brighter members of the Virgo cluster. It has a diameter of about 40,000 light years.

Lying close to M85 at a distance of only 8' to the E is the faint galaxy NGC4394. The latter is a magnitude 12 object some 3' in diameter which is visible in a 200-250 mm telescope on a good clear night.

M86
RA: 12h 26.2m,  dec: +12° 57'.

Constellation: Virgo.

M86 lies 1.25° WNW of M87.

Size: 7'x5'.

Magnitude: 9.2.

Distance: 20 million ly.

Object: elliptical galaxy.

In a small telescope, M86 appears similar to M84. Although M86 is often accepted as a member of the Virgo cluster of galaxies, its red shift is very low compared to the average for the cluster. One explanation for this, proposed by E Holmberg, is that M86 is a foreground galaxy and not a true cluster member. Holmberg's estimate for the distance of M86 is about 20 million light years, only about half way to Virgo cluster.

M87
RA: 12h 30.8m,  dec: +12° 24'.

Constellation: Virgo.

M87 lies about 1.25° W and slightly S of M89. M87 is bright and distinct and easy to find.

Diameter: 7'.

Magnitude: 8.6.

Distance: 63 million ly.

Object: giant elliptical galaxy.

M87 is a giant elliptical galaxy, in fact one of the largest known, with an estimated mass of 790 billion Suns. This is over twice the mass of M31, the Andromeda galaxy, and nearly four times that of the Milky Way.

M87 is unique in several other ways. It is surrounded by over 1000 globular clusters, about ten times the number surrounding the Milky Way. It is also one of the most powerful radio sources in the sky, the source of which seems to be associated with a bright jet of material, about 4100 light years in length, being ejected from the galaxy in a WNW direction. (Unfortunately, the jet is not visible in small telescopes.) M87 is also a very powerful X-ray source emitting over ten times as much energy in the X-ray band as it does at optical and radio wavelengths combined.

M88
RA: 12h 32.0m,  dec: +14° 25'.

Constellation: Coma Berenices.

M88 lies 1° W and 1.5° N of M90. M88 has a close pair of stars at its SE edge.

Size: 7'x4'.

Magnitude: 9.5.

Distance: 41 million ly.

Object: spiral galaxy.

M88 is a bright, multi-armed, spiral galaxy resembling a small version of the famous Andromeda galaxy, M31. It is a member of the Virgo Cluster.

M89
RA: 12h 35.7m,  dec: +12° 33'.

Constellation: Virgo.

M89 lies about 1° SSW of M90.

Diameter: 4'.

Magnitude: 9.8.

Distance: 41 million ly.

Object: elliptical galaxy.

M89 is an elliptical galaxy with no spiral structure. It presents a circular outline, but it may be an oblate spheroid seen from such an angle as to give a circular profile. It is estimated to have a mass of 250 billion Suns.

M90
RA: 12h 36.8m,  dec: +13° 10'.

Constellation: Virgo.

M90 is the most northerly of the Messier objects in Virgo and is a natural starting point for "galaxy hopping" to other Messier objects within the constellation.

Size: 10'x5'.

Magnitude: 9.5.

Distance: 41 million ly.

Object: spiral galaxy.

M90 is a fine, bright spiral galaxy discovered by Messier in 1781. It has a bright, almost stellar nucleus. It has a diameter of about 80,000 light years and is estimated to have a mass of about 80 billion Suns. M89 and M90 can both be seen together in the field of a low power eyepiece.

M91
RA: 12h 35.4m,  dec: 14° 30'.

Constellation: Coma Berenices.

M91 lies 1°E and slightly N of M88.

Size: 5'x4'.

Magnitude: 10.2.

Distance: 37 million ly.

Object: spiral galaxy.

M91 is a member of the Virgo group of galaxies. In good conditions, it can be seen with a telescope of aperture 150 mm. Larger apertures will reveal that it is brighter towards the centre.

M92
RA: 17h 17.1m,  dec: +43° 08'.

Constellation: Hercules.

M92 is easily found with binoculars. It forms a triangle with π and η Herculis and lies about 6° north of the former.

Diameter: 11'.

Magnitude: 6.4.

Distance: 28,000 ly.

Object: globular cluster.

M92 is a rich globular cluster in Hercules. It is often overlooked by the casual observer because of the presence nearby of the magnificent M13, but is a worthwhile cluster in its own right. The apparent diameter of the cluster is about 10' although, as is the case with M13, the visual appearance is somewhat smaller than this, with the greater part of the visible condensation lying in an area 6-7' in diameter. A 100 mm aperture telescope will provide some resolution at the edges of the cluster. Instruments of 200 mm aperture or larger provide spectacular views. The cluster is estimated to have a diameter of about 80 light years.

M93
RA: 7h 44.6m,  dec: -23° 52'.

Constellation: Puppis.

M93 is most easily located by reference to Sirius. Move 8° SE of Sirius to ο Canis Majoris and then sweep 10° E.

Diameter: 22'.

Magnitude: 6.0.

Distance: 3600 ly.

Object: galactic cluster.

M93 is a bright, compact cluster, but its southerly declination means that, from the UK, it can be successfully observed only when near culmination. The cluster has a triangular shape. It contains about 60 stars in the magnitude range 8 to 13. Under good, clear conditions M93 is a fine object for binoculars. A small telescope will resolve the brighter members of the cluster and will reveal the triangular shape. A telescope of 250 mm aperture will reveal about 50 stars within the cluster. M93 has a diameter of approximately 20 light years.

M94
RA: 12h 50.9m,  dec: +41° 07'.

Constellation: Canes Venatici.

M94 is easily found about 1.5° N of the midpoint of the line connecting α and β Canum Venaticorum.

Size: 11'x9'.

Magnitude: 8.1.

Distance: 32.6 million ly.

Object: spiral galaxy.

M94 is a compact, nearly circular spiral galaxy. In binoculars it appears almost stellar. In a 75 mm telescope it appears as a fairly bright, fuzzy star while a 250 mm telescope reveals it as a small, bright central nucleus surrounded by a much larger, faint outer region.

M94 has an estimated diameter of only 33,000 light years, much smaller than M51 and M63 (the other spiral galaxy Messier objects in Canes Venatici).

M95
RA: 10h 44.0m,   dec: +11° 42'.

Constellation: Leo.

To find M95 move 2.5° N and 3° E of the magnitude 4 star ρ Leonis. M95 and M96 can be seen together in the same low power view.

Size: 7'x5'.

Magnitude: 9.7.

Distance: 29.3 million ly.

Object: spiral galaxy.

M95 is a fine barred spiral surrounded by a ring of stars (visible in long exposure photographs). It is a member of the Leo group of galaxies which includes M65, M66, M96, NGC3338, NGC3423, NGC3628 and NGC3810. In a small telescope, M95 appears as a small, round glowing patch with a nucleus which is also small and glowing.

M95 has a mass of approximately 100 billion Solar masses.

M96
RA: 10h 46.8m,   dec: +11° 49'.

Constellation: Leo.

See details above for how to find M95.

Size: 7'x5'.

Magnitude: 9.2.

Distance: 29.3 million ly.

Object: spiral galaxy.

M96 is both larger and more massive than M95 and has about the same density. It is a spiral galaxy with a large central region showing little structure with many short spiral arms emerging from it.

M97
RA: 11h 14.8m,  dec: +55° 01'.

Constellation: Ursa Major.

M97 is small and faint and requires an aperture of at least 150 mm for visual identification. It is located 1.5° S and 2° following Merak (β Ursae Majoris). It lies 48' to the SE of M108.

Diameter: 3'.

Magnitude: 11.0.

Distance: 10,000 ly.

Object: planetary nebula.

M97 is the well known Owl Nebula. It is one of the largest planetary nebula but, unfortunately, has a low surface brightness and therefore appears as a featureless pale disk in most amateur telescopes. The "owl" face only becomes visible in large telescopes or long exposure photographs when two dark patches either side of the centre give the appearance of large eyes. M97 has a 14th magnitude central star with a very high surface temperature of approximately 85,000 K: it is one of the hottest stars known.

M98
RA: 12h 13.8m,  dec: +14° 54'.

Constellation: Coma Berenices.

M98 lies 0.5° W of the 5th magnitude star 6 Comae.

Size: 10'x3'.

Magnitude: 10.1.

Distance: 36 million ly.

Object: spiral galaxy.

M98 is a nearly edge-on spiral galaxy. It lies on the NW edge of the Virgo Cluster of galaxies but it is a foreground object and not part of the Cluster. It has a mass of 130 billion solar masses. It is a difficult object for a small telescope and good conditions are necessary to discern any detail.

M99
RA: 12h 18.8m,  dec: +14° 25'.

Constellation: Coma Berenices.

M99 lies only 1.3° ESE of M98.

Size: 5'x4'.

Magnitude: 9.8.

Distance: 41 million ly.

Object: spiral galaxy.

M99 is a member of the Virgo Cluster of galaxies. It is slightly brighter than its neighbour M98 but is, however, very indistinct towards its edges. It has a fairly broad central condensation and several small, bright patches which can sometimes be glimpsed visually in the S and E borders of the galaxy - these have led to it being termed the Pin Wheel galaxy. M99 is a relatively small galaxy with a mass of some 50 billion Suns and a diameter of some 50,000 light years.

M99 was the second nebula to be recognised as a spiral galaxy (by Lord Rosse in 1848).

M100
RA: 12h 22.9m,  dec: +15° 49'.

Constellation: Coma Berenices.

M100 lies 20' W and 3° N of M84.

Size: 7'x6'.

Magnitude: 9.4.

Distance: 41 million ly.

Object: spiral galaxy.

M100 is the largest spiral galaxy in the Virgo cluster. It is orientated almost face-on and appears as a circular, distinct glow with a brighter nucleus. It has a mass of approximately 160 billion solar masses and a diameter of approximately 100,000 light years.

M101
RA: 14h 03.2m,  dec: +54° 21'.

Constellation: Ursa Major.

M101 lies on the extreme eastern edge of Ursa Major, about 5.5° E of Mizar. It is faint and diffuse and may be difficult to find at first.

Size: 27'x26'.

Magnitude: 7.7.

Distance: 23 million ly.

Object: spiral galaxy.

M101 is a magnificent face-on spiral galaxy but, as with all such objects, it only reveals its true splendour in long exposure photographs. In small telescopes only the brighter central region, surrounded by a faint haze, is visible. In a 250 mm telescope it is possible to discern a hint of spiral structure. Photographically, M101 extends to about 20' diameter, twice its visual size. The galaxy has a diameter of about 90,000 light years, but its computed mass is only about 16,000 million suns, less than one tenth that of the Milky Way, making it among the least dense galaxies known.

M102
M102 appears to be one of the "missing" Messier objects. Méchain "discovered" it in 1781 but, two years later, wrote that it had been an error and was, in fact, a duplicate observation of M101.
M103
RA: 1h 33.2m,  dec: +60° 42'.

Constellation: Cassiopeia.

M103 can be found about 1° NE of δ Cassiopeiae. It is easily found with a good pair of binoculars.

Diameter: 6'.

Magnitude: 7.0.

Distance: 8500 ly.

Object: galactic cluster.

M103 is the last object in Messier's original catalogue. But modern versions of the catalogue have added objects through to M110 (one of the satellite galaxies of the Andromeda galaxy) as late as 1967!

M103 forms a fan shape about 6' in diameter and is a fine object for smaller telescopes with about forty stars in the magnitude range 8 to 12. In a large telescope with a low power eyepiece, M103 is brilliant. Like many galactic clusters, it contains a single, central, red giant star. The central star is of magnitude 10.8 with its colour standing out clearly against the other stars in the field.

M103 is some 15 ly in diameter.

M104
RA: 12h 40.0m,  dec: -11° 37'.

Constellation: Virgo.

M104 lies 24° S of the main Virgo cluster.

Size: 9'x4'.

Magnitude: 8.3.

Distance: 41 million ly.

Object: spiral galaxy.

M104 is the Sombrero Galaxy, a bright, easily found, edge-on, condensed spiral galaxy. It takes its name from a dark dust lane that lies through the centre of the object. The dust lane can be discerned with a 250 mm telescope. M104 is the most massive of the Messier galaxies, with a mass of 1300 billion Suns.

M105
RA: 10h 47.8m,   dec: +12° 35'.

Constellation: Leo.

To find M105 move approximately 1° N and a little E of M96.

Size: 5'x4'.

Magnitude: 9.3.

Distance: 21.5 million ly.

Object: elliptical galaxy.

M105 is a member of the M95 group of galaxies in Leo. In a telescope with large aperture (30 cm and above) it appears slightly oval.

M106
RA: 12h 19.0m,  dec: +47° 18'.

Constellation: Canes Venatici.

M106 is 2° S of the magnitude 5.5 star 3 Canum Venaticorum.

Size: 18'x8'.

Magnitude: 8.3.

Distance: 20 million ly.

Object: spiral galaxy.

M106 is much larger and brighter, and therefore more easily visible, than many Messier objects. It is visible in binoculars. The nucleus of the galaxy is bright; the outer areas are diffuse but against a dark sky can be traced to a large extent.

M107
RA: 16h 32.5m,  dec: -13° 03'.

Constellation: Ophiuchus.

M107 lies 3° SSW of ζ Ophiuchi.

Diameter: 10'.

Magnitude: 8.1.

Distance: 20,000 ly.

Object: globular cluster.

M107 is one of the late additions to Messier's Catalogue, but it is clear from his notes that he did observe it. P Mechain, a friend of Messier, discovered the object in April 1782. It is a small, faint object but a 150 mm telescope will show a hint of resolution at the edges.

M108
RA: 11h 11.5m,  dec: +55° 40'.

Constellation: Ursa Major.

M108 lies approximately 1.5° SE of Merak (β Ursae Majoris) and 48' NW of M97.

Size: 8'x2'.

Magnitude: 10.0.

Distance: 23.5 million ly.

Object: spiral galaxy.

M108 is a nearly edge-on spiral galaxy which displays a distinct elongated shape. It is easily visible in small telescopes with a hint of mottling across its surface.

M109
RA: 11h 57.6m,  dec: +53° 23'.

Constellation: Ursa Major.

M109 is easy to find, lying about 35' ESE of γ Ursae Majoris.

Size: 8'x5'.

Magnitude: 9.8.

Distance: 27 million ly.

Object: barred spiral galaxy.

M109 is easily visible in small telescopes as an elongated fuzzy object although only the central region is visible in typical amateur instruments. In large telescopes, the nucleus region has a mottled appearance.

M110
RA: 0h 40.4m,   dec: +41° 41'.

Constellation: Andromeda.

M110 lies 40' NW of the centre of M31.

Size: 17'x10'.

Magnitude: 8.0.

Distance: 2.2 million ly.

Object: elliptical galaxy.

A telescope with 200 mm aperture reveals M110 as featureless glowing ellipse.


David Payne