Orwell Astronomical Society (Ipswich)
Founding of Orwell Park Observatory
Colonel George Tomline (1813-1889), owner of Orwell Park Mansion from 1848 until his death, was keenly interested in all the science and technology of his era. His interests included astronomy, which at the time was a very fashionable and rapidly advancing science. In the early 1870s, he commissioned a major expansion to the mansion to provide the following facilities:
Tomline stipulated that the extra facilities be incorporated within the mansion. In the case of his observatory, his stipulation was contrary to the convention of the time, which was to site the private observatory of a wealthy landowner on high ground away from the main house so as to provide a good horizon and to isolate the astronomer from the disturbance and vibrations associated with domestic life. Tomline's requirement to incorporate the observatory within the framework of the mansion caused many additional considerations for the architect.
With essentially unlimited funds at his disposal, Tomline did not compromise on the construction of his observatory, and employed the leading designers and craftsmen of the day. As architect he engaged John Macvicar Anderson, partner and successor to the eminent William Burn, who had been responsible for earlier alterations to the mansion. He engaged Wilfrid Airy, son of the Astronomer Royal, Sir George Biddell Airy, to procure the scientific equipment for the observatory. Mr James Simms (of the firm Troughton and Simms) took charge of the construction of the astronomical telescopes. The leading optical firm Merz of Munich constructed the object-glass for the equatorial refractor. No contemporaneous documentary evidence has been located identifying the manufacturer of the huge cast-iron mount for the refractor but, in 1998, investigations by the late Mr Fred Dyer, historian of the Ransomes company, concluded that it was "almost certainly" cast by Ransomes, Sims and Head at the company's Orwell Foundry. Tomline employed Messrs George Smith & Co of London as building contractors for the observatory, including the dome and its mechanisms (running wheels, rotating mechanism and shutter) and Messrs Haden & Sons of Trowbridge to provide the heating arrangements for the Turkish bath suite.
Macvicar Anderson addressed Tomline's requirements with an innovative design of an observatory tower on five floors. He placed the Turkish bath suite on the basement and ground floor and the muniments room on the first floor. The second floor was at sufficient height to give a fine view over Tomline's lands, and housed the belvedere. On the top floor, he placed the equatorial room housing the 26 cm aperture, equatorially-mounted refractor nowadays called the Tomline Refractor.
The observatory became functional in mid-1874. There is no record of Tomline using it himself, and instead he relied on the services of a professional astronomer, John Isaac Plummer (1845-1925) to run it and make observations on his behalf. Plummer worked at Orwell Park until shortly after Tomline's death, observing a variety of astronomical phenomena, principally comets.
On 02 October 1874, Airy [1] published an account of Orwell Park Observatory in Engineering and, just a few weeks later, on 16 November 1874, Macvicar Anderson read a paper to the Royal Institute of British Architects (RIBA) on the design of the observatory; the paper was later published [2]. (Note that Airy's account in [1] is essentially repeated in his comments in [2] on the reading of Macvicar Anderson's paper.) The following extracts from the documents illuminate principal aspects of the facility.
Airy [1] described his considerations in choosing the site for the observatory. (In this, he clearly brought to bear his experience at Greenwich Observatory.)
The first consideration is the situation of the Observatory. The most favourable position is on the top of a low hill or rise of ground, so as to command the horizon all round without the necessity of raising the Observatory. For ordinary observations a clear view of the horizon is not extremely important, as the observations are much affected by refraction, but for extraordinary observations, for example, for the observation of a comet when near the sun, it is of great importance; and it must be borne in mind that the chief use as well as enjoyment of a private observatory consists in the careful examination of extraordinary objects. Again, if the observatory be near a river, an elevation of 100 ft, or 150 ft is often necessary in order to keep above the river fogs; these fogs commonly occur on cold nights in the winter when the sky is beautifully clear, and unless the observatory were above the fog the night would be lost. The writer has frequently seen a dense fog extending as high as 100 ft above the Thames at Greenwich, while at the Royal Observatory, 150 ft above the river, the air was perfectly clear and the stars brilliant. In the case of the Orwell Park Observatory it was desired that the Observatory should be attached to the mansion (which itself stands on a lofty bank overlooking the river Orwell), and since of necessity the Observatory had to be raised so as to clear the house and surrounding trees, the conditions as to elevation were amply secured. But, as might be expected, much expense and difficulty in construction, were caused by the great height of the Observatory, which will be referred to immediately. As a subsidiary matter of some importance, it may be mentioned that it requires some skill to secure a good architectural effect in an observatory attached to a mansion in the manner referred to; in the present instance, however, this matter received the most skilful attention from the architect, Mr. J. Macvicar Anderson, of Stratton-street.
He went on to enlarge on the mounting appropriate to the main astronomical instrument in an observatory attached to another building:
For the proper support of an astronomical instrument it is essential that a column or columns should be carried up from the ground without contact of any sort with the walls, floors, or other parts of the building. If this were not carefully attended to, such is the delicacy of the instrument that the effect of a person walking about any parts of the building adjacent would be rendered immediately perceptible at the instrument by a tremor very annoying to an observer. This condition is sometimes inconvenient, as in the case of the Orwell Park Observatory, for it was there necessary to run up a column 60 ft high to carry the instrument. This column was 10 ft in diameter at the bottom, tapering to 6 ft diameter at the top; the materials were brickwork in mortar; mortar is better than cement, as it is less subject to expansion, but the work needs to be carried up slowly to let the mortar set in so thick a mass of brickwork. The only disadvantage of brickwork is its high degree of elasticity, which gives some trouble in the case of a tall column while the work is fresh; probably except for the expense, stonework would be better. For the foundation of such a column, unless it was upon the natural rock, piling would seem best, as more effectually separating the column from shakes transmitted through the foundations. But in the case of the Orwell Park Observatory, piling was out of the question by reason of the many buildings closely adjacent, and it was necessary to set the columns on a large bed of concrete, which carried also the walls of the observatory. The foundation ground was sand, with much water.
Of the dome of Orwell Park he wrote:
With regard to the construction of domes for observatories, it is best to make the shell double, so as to prevent the observatory from getting too hot in the sun, and it would be well to have the skeleton of the dome of iron in order that it may keep a its shape and run true on the wheels: a wooden dome is apt to warp and run very heavy. The shutter of the dome should run easily and leave open a space from the horizon to beyond the zenith. Various arrangements of shutter have been adopted at different observatories, but there is none so convenient as that adopted at Orwell Park (see engravings on page 250), where the shutter runs on two tangent bars at the top and bottom of the dome respectively, and draws away to one side in order to open the slit.
The details of the Orwell Park dome will be understood from the engravings on page 259: the internal diameter is 20 ft, and the weight rather less than a 3 tons; the skeleton is of wrought iron, the internal casing is of polished mahogany, and the external casing (which carries the copper sheathing) is of thin deal. The moving power to turn the dome is applied by means of an endless rope on a grooved wheel; the axle of the wheel carries a pinion gearing into a circular rack which is fixed on the wall of the observatory, and the dome revolves with great ease by the power of one man applied at the rope. In some observatories the power is applied directly to one of the live-ring wheels which carry the dome, but this method is not always satisfactory, as the driving wheel is apt to slip, and it then becomes necessary to distribute the weight of the dome unequally, so as to throw more weight upon the driving wheel and increase the friction. The 0rwell Park dome was well constructed by the contractors, Messrs George Smith & Co.
Airy specified the main telescope at the Observatory as an equatorially mounted instrument of 26 cm (10") aperture, justifying his choice as follows:
In designing an equatorial instrument, the first consideration is the size of the object-glass (which will rule the size of the instrument, and the size of the observatory); the next consideration is the system of mounting which shall be adopted; and the last is the construction of the object-glass and instrument. As regards the size of the object-glass, it may be observed that in the hands of a skilful observer a 6-inch glass is sufficient for most observations, and a very large part of the delicate work done in modern times, such for example as the discovery of small planets, has been done by means of 6-inch glasses; but for the careful examination of the moon and planets a larger glass adds greatly to the enjoyment of an observer. In spectroscopic and other observations of recent interest also, in which the amount of light is of great consequence, a large glass is almost essential. But the point of first importance is the definition and purity of the glass, and the difficulty of insuring these requisites increases rapidly with the size of the glass. There have undoubtedly been made object-glasses of large size, 15 inches and upwards, of great excellence, but it in the opinion of the writer, a 10-inch glass is the largest that can at present be relied upon for superior excellence when made to order. The object-glass of the Orwell Park Observatory is a 10-inch glass. It would probably be advisable, in all cases, to order a glass from a professed manufacturer of astronomical object-glasses. There are, unfortunately, not many such manufacturers, and the best are foreigners, but they have a great advantage in possessing always in stock a large number of lenses of all sorts, and by fitting together different lenses (so as to form an object-glass, which is compounded of two lenses) they are generally enabled to insure an object glass of great excellence. The object-glass of the Orwell Park Observatory was procured from Messrs. Merz, of Munich, and is an excellent glass.
Airy assured himself of the quality of the object-glass by comparing its performance with that of the 33 cm (12.8") Great Equatorial refractor at Greenwich:
In no case should a glass be accepted without being tested, and to test a glass requires the skilled eye of a practical observer. Probably the best method of testing a glass is to compare it by observation of a star with a similar glass of known excellence. In the case of the object-glass for the Orwell Park instrument, the writer obtained permission to attach a temporary tube containing the glass to be tested to the polar axis frame of the large equatorial at the Royal Observatory; the two telescopes were then turned upon the same star, and a comparison instituted of their efficiencies. The best object to observe as a test of definition is a bright double star (both stars of which are bright), Zeta Bootis, for example; if the two stars of the double star stand distinctly apart, it is a good glass. Also every star should appear in the glass as if surrounded with several concentric thin black rings (known as diffraction rings). These rings may be accounted for theoretically, and their existence is a strong proof of the accuracy with which the lenses have been formed.
His design for the mount of the equatorial refractor at Orwell Park was innovative and combined the advantages of the English and German styles:
There are two methods of mounting equatorial telescopes in common use, which are known as the English and German methods respectively. According to the English method, the polar axis frame is carried by two powerful standards, placed at the north and south sides of the observatory respectively, and the telescope is slung midway between them. The advantages of this arrangement are, that the long polar axis admits of very accurate adjustment of the instrument, the telescope is easily accessible in all ordinary positions, and the floor of the observatory is not hampered by a central pier, as in the case of the German method of mounting. The disadvantages are, first, that however stiff the polar axis frame may be made, yet the weight of the telescope will cause a sensible deflection of the polar axis; secondly, that the north standard sometimes obstructs the view of an object in the north; and thirdly, that the total weight of the instrument and the polar axis frame is considerable. According to the German method of mounting, the polar axis is much shorter than according to the English method, and it is carried entirely by a single standard, which is commonly vertical, and placed in the centre of the observatory, the telescope being carried on the upper end of the polar axis. The advantages of this method are the compactness, steadiness, and ease of motion which it admits of. The disadvantages are the shortness of the polar axis, the small size of the hour circle, and the inconvenience of the central pier, which brings up the telescope when following a star within 20 deg. or 30 deg. of the pole, and so compels a readjustment of the telescope. In the case of the Orwell Park instrument the writer adopted an arrangement which he thinks secures all the advantages of the German method, and avoids the disadvantages of the English method above referred to. The standard is a very powerful casting, and is cast in a bent form (sec dotted lines in Fig. 1, page 259) so as to permit the telescope to clear the standard when following any star whatever; the polar axis is produced to the floor, and its pivot end is carried by a solid bracket which forms part of the standard casting; this arrangement admits of a 3-foot hour circle. The telescope is carried on the north end of the polar axis, as in the German method. The weight of the standard casting is rather more than two tons.
Macvicar Anderson [2] gave an overview of the architectural considerations involved in the design of Orwell Park Observatory:
To design an Observatory cannot fail to be, I should think, under any circumstances, a work of considerable interest, calling for the exercise of great care and no small amount of ingenuity; but when, as was the case at Orwell Park, the Observatory had to be connected with an existing edifice, so connected as to admit of faculty of access, and to combine with the somewhat complicated domestic arrangements of a country mansion, and yet so isolated, as to secure complete privacy and perfect quiet to the astronomical observer, the difficulties, I apprehend, are intensified to no small extent. As the Observatory, of which I am now about to give some account, formed only a portion of other works which I was called upon to design at the same time in connection with the house at Orwell Park...
He went on to provide details of the modifications required to the mansion:
The original house consisted of a square block, to which had, at various times, been added the several adjuncts you see on the large plan, such as the picture gallery, billiard room, and conservatory to the west, and an entirely new wing to the east, embracing the whole of the domestic offices, &c. In connection with these additions the main block of the mansion had, so far as the south front is concerned, been refaced, and made to assume the architectural garb it now possesses. These operations had, at different periods, been carried out by the late Mr Burn. Such was the subject for treatment. The requirements of the proprietor were, one or two suites of first class bedrooms, in which the house was deemed to be deficient, forming state apartments, a Turkish bath, and, though last not least, an Observatory, with other minor and subsidiary wants not necessary to specify. The main building, comprising the principal apartments, was complete in itself, and answered every purpose required of it. The east wing, comprising the domestic offices, was excellently arranged in point of comfort and convenience, and of a substantial character. It was clear, therefore, that neither one nor the other could be materially altered without disturbing arrangements which were good, and incurring a large and unnecessary outlay. Accordingly I resolved to adopt an arrangement which possessed the merit of retaining the whole of the existing buildings intact, with some unimportant exceptions - while it extended to more than double its then length the principal architectural front of the building, and obviated the inconvenience of the servants' offices overlooking the private grounds. This was done by building up the whole of the windows of the offices which looked to the south, and (by the sacrifice of one or two servants' bedrooms only, which were obtained elsewhere) lighting and thoroughly ventilating from the roof the offices which had previously looked to the south, an operation which proved perfectly successful and satisfactory. This simple expedient solved all difficulty, for the whole space to the south of the east wing was thus made available for the erection of an entirely new wing, comprising the additional accommodation that was required, shutting out from view the ugly and unfinished appearance of the old east wing, and completing the architectural facade of the building to the south. This new wing consisted of a handsome suite of apartments on each floor, so arranged that the rooms might be used together or separately, as occasion required, accessible on both floors by means of a corridor 170 feet in length; in connection with which was provided a new principal staircase, a feature of which the house was in want. At the extreme easterly end of this new wing I placed the Observatory, thereby providing a handsome and convenient access from either floor, by means of the corridors already mentioned, and at the same time securing that complete isolation that the peculiar circumstances of the case called for. The rooms on the principal floor were arranged so that they might be used as a complete suite of family apartments, the proprietor's business room being at the east end of the suite, in close proximity to which - but properly shut off - were the Turkish bath chambers, and in immediate communication with which was the observatory above, by means of a private staircase.
He considered the position of the Observatory as follows:
At Orwell Park the Observatory, although standing on high ground, had necessarily to be of considerable height, in order to surmount the adjacent buildings and lofty trees in the vicinity. It was stipulated by Mr Airy that the floor of the equatorial room should be 6 feet below the top of the highest chimney in the mansion adjoining, a stipulation which involved a height of 53 feet from the ground level, and of 72 feet to the top of the dome, the total height from the bed of the foundations to the top of the dome being 86 feet. In selecting the site of an observatory, it is important that the situation should be dry and free from moisture, and it is to be further noted that when it is in the vicinity of a river, the observatory should be placed at such an elevation as to be above the reach of fogs, for such may prevail when the sky above is clear and well adapted for astronomical observations.
He described his interpretation of the pillar, specified by Airy upon which to mount the equatorial refractor, and how he decoupled it from the remainder of the mansion:
In the case of Orwell Park, Mr. Airy stipulated that the instrument should be supported upon one central pier or pillar, circular on plan, and carried up from the foundation to the height of 60 feet in one solid and unbroken mass of brickwork. At the base, and for the height of 12 feet, this pier was 10 eet in diameter; from this point to the height of 32 feet it was 8 feet in diameter; and for the remaining 16 feet it was 6 feet in diameter. It is perhaps superfluous to state that the brickwork of this pier was of the very best description; but it is worth noting that it was built in, mortar, not cement, by Mr. Airy's special desire, the former material being less subject to expansion; and the precaution was taken of carrying up the work slowly, so as to allow the brickwork to set thoroughly throughout the entire mass of the column. At the level of 7 feet from the top of the pier, a 12 inch hard York stone, from the Idlestone quarry, was inserted, 6 feet diameter, and again on the top of the pier a similar stone was bedded, which latter formed the upper surface of the column at the exact level of 3 feet 10 inches below the floor of the equatorial room, and to this stone was afterwards fixed the iron casting which formed the support of the instrument.
The one point of supreme importance, which required to be specially attended to in connection with this pier was, that it should have absolutely no contact whatever with any portion of the surrounding building, from the foundation upwards, just as much so indeed as if it had stood by itself, an isolated pillar. To effect this object I encased the pier with a circular wall of 14 inch brickwork the whole height from the foundation upwards to the floor of the Observatory, leaving a clear space of 6 inches throughout between the outer surface of the pier and the inner surface of the enclosing wall, and thus it became utterly impossible that the pier could be, even to the smallest extent, affected by its proximity to the surrounding buildings. The diameter of this circular well, as it might be called, was made to diminish upwards, following the diminishing diameter of the pier which it encased, so as not to lose space in the surrounding building, which might prove valuable for other purposes. The internal diameter of the dome of the Observatory was fixed by Mr. Airy at 20 feet in the clear, and the circular walls which supported it and formed the equatorial room, were consequently required to enclose a space 19 feet 6 inches diameter. It is obvious that had these walls been carried up from the foundations, the space between them and the 14 inch wall enclosing the pier would, especially towards the bottom, have been so limited as to have been practically useless. On the lower floors, therefore, I constructed the building of a much larger diameter, and of octagonal form, measuring 32 feet from out to out. By this means I obtained a space all round the central pier, 7 feet 6 inches in the clear between the external walls and the 14 inch inclosing wall already alluded to.
His description of the Turkish bath suite revealed the degree of luxury which Tomline specified:
This space in the principal floor appeared to me well adapted for what was one of the requirements of the Proprietor, a Turkish bath. I therefore formed an adjunct to the Observatory building on this floor, and placed therein the "sudarium" and "tepidarium," being the two hot chambers, and reserved the whole of the space surrounding the central pier of the observatory for the "frigidarium " or cooling chamber. These chambers were heated by a special furnace, placed in the basement Immediately beneath, capable of raising the temperature in the innermost or hot chamber to 200 degrees, and a proportionate amount of warmth was also introduced to the other chambers, the whole being so arranged that the temperature in each chamber could be regulated as might be desired. The cooling chamber, which occupied the space around the central pier of the Observatory, was of octagonal form, and was proposed to be finished in a style of Oriental luxuriance, with shafts of polished marble, a dado and wall linings of coloured marbles, and a veined marble floor, the groining, which was executed in plaster, being intended for coloured and painted decoration. The large recesses were prepared for luxurious couches, and the chamber was thus intended to form a sumptuous and agreeable lounge for general purposes, as well as for the more immediate requirements of the Turkish bath.
A Glaswegian by birth, Macvicar Anderson was a nephew of W Burn. Following a local education and upon graduating from Glasgow University, he went to work in his uncle's prestigious London architectural practice. In the course of his career he designed a number of mansions in England, Scotland and Ireland including: Althorp (Northampton), Brampton & Blankney Hall (Lincs), Cheswardine Hall (Shrops), Iden Manor and Wilderness (Kent), Powercourt (Ireland). He was also responsible for some impressive commercial buildings, including a number of banks in the City of London and Coutts Bank in the Strand [3]. His other works included the Carlton Club (amongst a number of private London clubs), many private homes of the rich and the Royal Scottish Hospital and Royal Caledonian Asylum. He served as Secretary to RIBA 1881-89 and President 1891-94. His very successful career brought wealth and fame and he lived in one of London's most exclusive areas - Stratton Street, Mayfair [4].
Wilfrid was the fourth of nine children born to Sir G B Airy (7th Astronomer Royal) and his wife Richarda [5]. The first three children died in childhood and Wilfrid became the eldest surviving child. He was born at the Royal Observatory just a year after his father had taken office there and he cannot but have been influenced by his surroundings. Indeed, some of Wilfrid's experience of the workings of the Royal Observatory helped to shape his ideas for Orwell Park.
Wilfrid helped and accompanied his father on many official trips abroad. For instance, he was a member - along with his parents and one of his sisters - of Warren De La Rue's 1860 British Himalaya Expedition to Spain (the expedition was named after the ship the expedition chartered) to observe a total solar eclipse [6]. However, Wilfrid moved away from a purely scientific career path and qualified as an engineer.
It could be said that Wilfrid's father brought about his meeting with his future bride. Airy senior maintained excellent links with the scientific establishment on mainland Europe and he and Richarda were particular friends of Professor Listing at the Gottingen Observatory. Wilfrid married Professor Listing's younger daughter, Anna, in 1881. Sadly, the marriage was cut short just a year later when Anna died giving birth to a daughter also named Anna. Wilfrid was left to bring up Anna alone and settled at the family home in Playford. He died there in 1925, leaving the house to Anna. She became a renowned artist and lived at Playford until her death in 1964. The older residents there still remember her quirky ways and indomitable spirit.
Historical footnote: the Airy family has kindly donated Wilfrid's scrapbook of papers and articles to OASI for safe keeping in the library.
George Tomline.
John Macvicar Anderson. (RIBA Presidential Portrait, by Charles Furse RA, 1893. Reproduced by kind permission of RIBA.)
Wilfrid Airy. (Reproduced by kind permission of the Airy family.)
Anna Airy. (Reproduced by kind permission of Mr B Seward.
Redrawn from [2].
The observatory tower.
Equatorial room and ground floor.
Observatory Dome with the Tomline Refractor inside.
Winding wheel used to rotate the dome.
Plans for Orwell Park Mansion and Observatory by John Macvicar Anderson, 6 Stratton Street, London, May 1871. Obtained from the Royal Institution of British Architects.
Basement floor.
Principal floor.
Bedroom floor.
Rooftops.
New wing and observatory.
New wing & observatory, elevation.
From "Engineering", 02 Oct 1874, pp. 257-259.
From "Transactions of the Royal Institution of British Architects", 1875, pp. 15-26.
[1]
Wilfrid Airy, The Orwell Park Observatory, Engineering, 02 Oct 1874, pp. 257-259.
[2]
John Macvicar Anderson, The Orwell Park Observatory, Transactions of the Royal Institution of British Architects, 1875, pp. 15-26.
[3]
In the early 1990s, most of Coutts Bank was demolished during remodelling of the Charing Cross area. However, Macvicar Anderson's stylish facade was retained and now fronts an entirely new commercial complex.
[4]
Obituary in The Builder, 18 June 1915.
[5]
Richarda also suffered a number of miscarriages.
[6]
The First Photographic Eclipse?, by P D Hingley, in "Astronomy & Geophysics", February 2001, pp. 1.18 - 1.22. This expedition is thought to be the first to successfully photograph the phenomenon and which, according to Hingley, "led to the first definite scientific result to be found from astrophotography" - it settled the question of the cause of the phenomenon known as Bailey's Beads.
Ken Goward, FRAS