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    Re: Kew Observatory and Wikipedia
    From: Frank Reed
    Date: 2010 Mar 5, 00:28 -0800

    Douglas, you wrote:
    "It confirms as I suspected that the Kew Observatory was for some considerable time a branch of the Admiralty"

    Kew Observatory was not a branch of the Admiralty at any time, despite its work testing sextants, chronometers, thermometers, barometers, etc.

    There's a good article on the history of Kew Observatory in the "Record of the Royal Society" for 1897. For what it's worth, according to this article and others Kew Observatory was managed by the Crown from 1769 when it was built by George III (acquiring sometime later the name Kew, from an earlier observatory, despite being built in Richmond) until 1842 after Queen Victoria had decided it was no longer useful. From 1842 to 1871 it was run the British Association for the Advancement of Science with progressively greater input from the Royal Society, becoming from this date primarily a meteorological and magnetic observatory. From 1871, following the bequest of a substantial endowment, through the last day of 1899, Kew Observatory was operated by the Royal Society. The observatory was taken over, with little change in function or staff, by the new government-run National Physical Laboratory on January 1, 1900. The sextant certification work was transferred to the larger N.P.L. facility in Teddington in about 1910 and from that date Kew Observatory was transferred to the Met Office. Kew Observatory remained an important location for meteorological work and was also later an important seismological station.

    According to that 1897 history, sextant certification work was performed at Kew Observatory from 1862 (with an early heliostat system developed by the famous Francis Galton which, according to his memoirs, due to "the uncertainty of sunshine in our climate proved to be of little practical value) and with greater success using Cooke's collimation system starting in 1869. As noted above the collimation equipment was removed to Teddington in 1910. The sextant room at Kew Obs was a little, dark room in the basement in the southeast corner of the observatory, about 100 square feet, adjoining the caretaker's apartments (starting in about 1884, sextant shades were tested separately, two floors directly above the sextant room). The instrument for testing sextant arc error consisted of "five collimating telescopes, with gas jets behind them, which illuminate objects, in the shape of crosses, situated at the principal foci. The collimators are fixed on a slate slab, carried by brickwork. The emergent beams of light converge to a common centre, and are inclined at certain known angles. The readings given by a sextant for the magnitude of these angles supply the data for determining the error at various points in its arc." Given that this service had been available since the 1860s, it's interesting to read this: "In 1888 the Admiralty made a regulation that all sextants used by cadets of H.M. Navy must be certificated at Kew." That seems like a remarkably late date to put this requirement into effect, but I would imagine that it had a powerful effect on sextant manufacturers. This same history notes that Kew Obs began rating watches (and chronometer watches) in 1884 following "pretty closely" the Geneva system, and that the observatory also rated marine chronometers starting in 1888.

    From "Nature" 1910:
    "The work of testing instruments now carried on at Kew Observatory by the National Physical Laboratory will be removed to Teddington as soon as the necessary provision for its transference can be made. The laboratory will retain the well-known K.O. mark for use with those classes of instruments which have hitherto been tested at the observatory."

    ...proving George Huxtable's comment.

    An article by Tom Blaney from 2001 adds, "Galton also introduced in 1878 the 'KO' monogram, which was marked on thermometers, and later on other instruments that met the Kew standard."

    Note that editions of Lecky's "Wrinkles in Practical Navigation" published after 1910 still contain the marginal note "Instruments can be tested at Kew Observatory" and the suggestion to "pack the instrument off to Kew" but the address has been updated to reference Teddington as follows:

    "Before finally deciding to purchase an expensive sextant or quintant, arrange with the maker to have it tested, and its errors determined and tabulated at the National Physical Laboratory. The fee is a trifling one -only five shillings, exclusive of carriage to and fro. Any person ordering instruments from opticians may direct them to be previously forwarded there for verification. Address— The Director, National Physical Laboratory, Teddington. In these pages it has been shewn how to test the mirrors, also the parallelism of the shades, but to test the centering errors is practically beyond the power of the navigator. If a man of infinite resolve, he may succeed, it is true, by vexing his soul with a series of astronomical observations of a painfully tedious character. Much better to pack the instrument off to Kew, where, by a system of collimators, the centering errors are determined for every 15° of arc both quickly and accurately."

    Incidentally, the year of the completion of the observatory, 1769, should sound astronomically significant to many of us. That's the year of the great Transit of Venus. King George III had it constructed supposedly for the "amusement" of the royal family, so that they could observe the transit themselves. While Cook and the astronomers were watching in Tahiti, King George was watching in England...

    Today it seems that the observatory is generally known as "King's Observatory" again. If you would like to see it in its current setting, go to Google Maps or similar at these coordinates: 51.4689 N, 0.314159 W (just seeing if anyone's paying attention). You will discover that it is smack in the middle of the Royal Mid-Surrey golf course. When I saw that, I first thought it was a modern development, but it turns out that golf balls were bouncing around Kew Observatory starting in 1893 in its heyday of sextant testing. A fence around the observatory to protect it from golfers and presumably golfballs was funded by Galton himself. The observatory's magnetic and meteorological observations ended in 1980. The Met Office moved to better quarters. The building was refurbished and leased as offices. Apparently the band "Pink Floyd" held an option to rent it, but eventually it was rented for many years by Belron, a glass company. According to one source, it was converted into a private residence within the past year. Must be nice!


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