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The Illustrated London News 28 August 1852 by kind permission The Illustrated London News ©2002 The Craig Telescope At Wandsworth Common During the past three months, the construction of a building on Wandsworth Common, for the reception of a monster achromatic telescope, has been rapidly progressing, and is, with telescope itself, now nearly completed. This great work is under the supervision of William Gravatt, Esq., F.R.S., or Rev. Mr. Craig, vicar of Leamington. The site, consisting of two acres, has been liberally presented by Earl Spencer, in perpetuity, or as long as the telescope shall be maintained.
The Duke of Northumberland's telescope is foreign, the Oxford telescope is foreign, Sir James South's telescope is foreign, in fact, these instruments were merely purchased by English money. Not so the present instrument, by far the largest achromatic telescope in the world. In the retired study of a country clergyman, the idea of this instrument struck him, and having made in his own peculiar way his calculations the result was a fixed determination to carry them out, which he has more especially shown in the choice of his engineer, for many were those he had to reject, after looking into their plans of mounting his telescope. He has selected Wm. Gravatt, Esq., FRS, whose name, we believe, Mr Craig, is more desirous to connect with his wonderful telescope than his own. The powers of this Telescope, as a measuring instrument, are unapproachable by all others. It separates minute points of light so distinctly that its space penetrating qualifications will render it, as a discovering instrument, one of a most superior order. It resolves the Milky Way, not simply into beautiful and brilliant 'star dust', to use the language of astronomers, but actually subdivides it into regular constellations. We thus in what at best was heretofore separated into minute points of light, can now behold counterparts of our own Orion and Cassiopeia, our Greater and Lesser Bears and also evidently adorned with the most generous colours. The Telescope is perfectly achromatic; Saturn exhibits itself with milky-light whiteness. Now that the instrument is adjusted, Mr Craig wishes the Planet Venus to be examined, for he hopes to settle the question as to whether she has a satellite or not, and we need not say what an advantage the solution of this fact would be to science. The moon is a magnificent object and perfectly colourless, so that the observer can behold her mountains and rocks with a vivid distinctness that makes us long for clear weather to bring the whole of the powers of this marvellous instrument to bear upon our planet. On a favourable evening, were such a building, for instance, as Westminster Abbey in the moon, this Telescope would reveal all its parts and proportions. The central tower is of brick, and 61 feet in height, 15 feet in diameter, and weighs 220 tons. Every precaution has been taken in its construction to prevent the slightest vibration, which can still further be provided for by loading the several floors, and the most perfect steadiness will be thus ensured. By the side of this sustaining tower hangs the telescope. The length of the main tube, which is somewhat shaped like a cigar, is 76 feet, having an eyepiece at the narrow end, and a ducap at the other: the total length in use will be 85 feet. The design of the ducap is to prevent obscuration by the condensation of moisture, which takes place during the night, when the instrument is most in use. Its exterior is of bright metal: the interior is painted black. The focal distance will vary from 76 to 85 feet. The tube at its greatest circumference measures 13 feet, and this part is about 24 feet from the object-glass. The determination of this point was the result of repeated experiments, and minute and careful calculation. It was essential to the object in view that there should not be the slightest vibration in the instrument, and Mr Gravatt has made the vibration at one end of the tube neutralise that at the other. The ironwork of the tube, which is a splendid specimen of English workmanship, was manufactured by Messrs. Rennie, under the direction of Mr Gravatt. The tube rests upon a light wooden framework with iron wheels attached, and is fitted to a circular iron railway at a distance of 52 feet from the centre of the tower. The chain by which it is lowered is capable of sustaining a weight of fifteen tons, though the weight of the tube is only three. Notwithstanding the immense size of the instrument, it can move either in azimuth, or up to an altitude of 80 degrees, with as much ease and rapidity as an ordinary telescope, and from the nature of the mechanical arrangements, with far greater certainty as to results. The slightest force applied to the wheel on the iron rail causes the instrument to move round the central tower. All the optical work has been executed by Mr. F. Slater, of Somer-place West, Euston-square. The two lenses, one of flint and the other of plate glass, are thus used: - The plate-glass lens has a positive focal length of 30 feet 11/2 inch; its refractive index is 15103. The flint-glass lens has a negative focal length of 40 feet 101/2 inches; and the refractive index of this glass is 16308. These two lenses, placed in contact, are used in combination, and constitute the achromatic object-glass, the focal length of which is 76 feet to parallel rays – that is, to all celestial objects. back to top of page >>
Friday March 11 1955 Letters to the Editor - "The Scope" Sir, You ask in your comment today for the origin of the name, "The Scope", for the part of Wandsworth Common where the recent murder was committed. The name is undoubtedly an abbreviation of "The Telescope". In 1852 a small segment of the Common at the end of Lyford Road was enclosed and the Rev. John Craig erected there a brick tower over 60ft high, from the top of which swung a cigar-shaped telescope, 70ft long with a two-foot object-glass, swivelling at its lower end on a small circular railway. Though it was an imposing landmark it never fulfilled its owner’s hopes. He was apparently ruined, the building fell into disrepair and the dismantled telescope was to be seen as lumber in the builder’s yard in Wimbledon Park Road in the early eighteen eighties. The ground on which it had stood again became part of the Common. A small water-colour sketch of it is in the Guildhall Museum and one of my early maps names a small triangular section of the Common "Telescope". Further to your report today that the Historical Society is seeking illustrations of the Southfields area, it occurs to me that this district has changed so completely in the last sixty years that residents might not recognise such pictures if they saw them. Some idea of what to look for might be helpful. A favourite viewpoint was from the top of the Leg of Mutton Field (now Skeena Hill) across a large pond called The Hollows. This was before the railway came and, apart from one cottage, there were no buildings in Granville Road which was a country lane between hedges, with a stream at one side in wet weather until you reached the corner where St. Michael’s Church stands today. Practically everything was hayfields and grazing land. There should be many sketches and some photographs of the old Half Mile Road that extended from this corner to Elm Lodge (now the site of Southfields Station). Yours faithfully E. P. Olney 122 Kenilworth Court Putney SW17 back to top of page >>
by kind permission of R. Derek Wood Advance of Science, British Association Report for 1854, Part 2, pp. 10-12 item 48a. from 'Bibliography of J. B. Reade On Photographs of the Moon and of the Sun Rev. J. B. Reade, M.A., FRS Abstract: After discussing a daguerreotype of the moon taken by Bond in the USA and two calotypes by H. Pollock, Rev. J. B. Reade reports on pages 11-12 how a group of astronomers, including himself, at Craig's telescope at Wandsworth used collodion negatives prepared by Prout and printed by Dr. Hugh Diamond. History of Early Photography website at www.midleykent.fsnet.co.uk The Athenaeum, 14 October 1854 pp. 1240-1 by kind permission of R. Derek Wood "[mag-]nifying power. Dr. Diamond, who printed the positive of the moon, found the sun picture, however, rather overdone for transferring. "It will be necessary, therefore, either to use collodion and nitrate of silver simply without any or but little sensitive solution or else pass the sun's rays through some coloured glass, which will partially retard their energy. A series of pictures of the spots of the sun, as well as of the general surface, may then be successfully obtained; and hence it is not too much to anticipate some accession to our knowledge of the physical character of both our great luminaries by means of this gigantic telescope, which Dr. Diamond enables me to exhibit photographically to the [Astronomy] section. "The above text of Reade's paper read at the annual meeting of the British Association of 1854 (held that year in Liverpool) had first appeared with an additional first paragraph in The Athenaeum, 14 October 1854, pp. 1240-1. In addition a short mention of this contribution by Reade to the 1854 meeting appeared in The Art Journal, 1854, Vol. 6, p. 368 Many years later at a meeting of the Photographic Society of London (which later became the present Royal Photographic Society) Reade recalled the use of a yellow filter when taking photographs with the telescope at Wandsworth. At the meeting of Photographic Society on 8 December 1868 (at a period when Reade was often the chairman, although not on this particular occasion, when the Photographic Society vice-President was in the chair, interesting for anyone interested in the history of Astronomy in being the more well-known James Glaisher!) an illustrated talk had been given by H, Baden Pritchard on ' Photography in connection with the Abyssinian Expedition'. My Bibliography of J. B. Reade lists Reade's published remarks as follows: "item 87. Rev. J. B. Reade, remarks at the Photographic Society meeting of 8 December 1868, on previous use of a yellow glass filter to control exposure when obtaining photographs of Sun through large telescope, Photographic Journal 11 December 1868, Vol 13, p. 187. A slightly different version in the third person of these remarks also appeared in report of the meeting in British Journal of Photography, 11 December 1868, Vol. 15. p. 594" It will be noticed in that journal the "large telescope" is not named, but this does appear in the Photographic Journal's own report of Reade's remarks: "...referring to the difficulty said to have been experienced in limiting the exposure on certain occasions in consequence of the excessive chemical activity of an African sunshine, the speaker [Pritchard] proposed the use of a pale yellow glass placed within the camera, or adapted to the front of the lens; such an expedient was successfully resorted to whilst photographing the sun's disk in the large telescope belonging to Mr. Craig of Wandesworth, and it would no doubt answer the purpose of diminishing the intensity of the light when thus applied to an ordinary camera." R Derek Wood's "Bibliography of Joseph Bancroft Reade FRS (1801-1870)" remains unpublished but there is a copy deposited at the Royal Society Library and Archives: Royal Society Catalogue R.63128, shelf-mark Tracts X499/3. A printed copy does also exist at the Royal Photographic Society library at Bath but the Royal Society copy is what is counted as the archived source. There is also a PDF file of Part 1 of the Bibliography available on the Midley History of Early Photography website at www.midleykent.fsnet.co.uk. back to top of page >>
by kind permission of Mr Stewart McLaughlinback to top of page The general history of the very large refracting telescope built in the 1850s for the Reverend John Craig is well known and is documented in a variety of contemporary and later sources. A brief history of this instrument may, however, be useful and suffice to set the scene. In 1852 the Reverend John Craig, vicar of Leamington, had a huge telescope with a 24-inch (610-mm) objective built by Messrs Rennie under the supervision of a Mr Gravatt FRS. It stood on a piece of land, provided by the Earl Spencer, just south of Wandsworth Prison. The large objective lens and all other optical works were executed by Thomas Slater. The 75-ft-long (22.8-m) cigar-shaped metal tube was attached to a 64-ft (19.5-m) high tower by chains, which allowed it to be raised and lowered. The tower was 15 ft in diameter, weighed 220 tons and had a rotating top to allow radial movement of the telescope. The eyepiece focusing assembly was mounted on a wooden trolley which ran on a circular track of 52 ft (15.8 m) radius. This unusual construction was visible to passengers travelling on the railway line which ran nearby. For the few years of its existence it was probably as familiar a sight to them as Herschel’s large telescope had been to stagecoach travellers on the London road past Windsor in the previous century. The telescope’s objective was not, however, of high quality spherical aberration was so pronounced that the central part of the objective had to be stopped out. There is no evidence that any serious systematic observational work was carried out with the instrument. In 1854, Craig’s wife Helena died an in 1858 Craig stopped using the telescope. The telescope and supporting structure were subsequently dismantled. In 1990, having lived for many years in the area, I decided to try to determine the exact location of the instrument and to see if any remains could be found. The approximate location of the Craig Telescope was confirmed by a visit to the local history library but the original description of ‘a 2-acre site south of Wandsworth prison was too vague to identify the actual site. Eventually, however, a map was found, dated 1862, published by Stanford’s of Charing Cross, London, which showed an observatory site and enough detail to match it to modern maps at the corner of Lyford Road and Routh Road. A site visit showed that the area of the common where the telescope stood is now heavily overgrown. No obvious evidence of any remains of the tower could be found, although the foundations to support a mass of 220 tons would be been substantial and may still exist below ground level. The sole remaining (circumstantial) evidence of the structure seems to be the three iron rail stumps, which are used as bollards at the northern end of the site at Lyford Road. These may well have been from the circular track that carried the eyepiece trolley. The ends appear to be cut for fitting in a circle and there are only single fish-plate holes, rather than the two commonly used for actual railway lines. Their use as bollards at the end of a path suggests they were acquired locally. Two other items of interest emerged from this initial investigation. Firstly, it would appear that older residents of the area still referred to the site as ‘Scope corner’ until quite recently – a nickname which was in general use until well after the end of the Second World War. Enquiries also revealed that bricks for the telescope’s tower were probably fired locally at an area near the common known as the ‘Frying Pan’. Bricks for Wandsworth Prison were cast there from 1849 to 1851. This is as afar as the investigation has been able to progress at present. If any members can provide further information which would help to prove that this area was the actual site of the Craig Telescope I would be very pleased to hear from them. S McLaughlin Tooting, London back to top of page >> |
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