Surveying Instrument Collection
Maker |
Wild, Heerbrugg, Switzerland |
Model |
30° Prismatic Astrolabe Attachment for Theodolite (T2) |
Serial Number |
none |
Dimensions |
115 x 90 x 100 mm |
Image |
|
Description |
Astrolabe attachment for the telescope of Wild T2 theodolites. It features a disk for the mercury horizon, a 60° equilateral prism for the deflection of the line of sight onto the mercury horizon and then upwards. It carries a spot bubble and slow motion drive for the levelling of the device in trunnion axis direction. The pool dish has a transport cover and a glass cover to protect the mercury pool during observations. The case includes a glass bottle filled with mercury inside a protective wooden container, the top of which doubles as a funnel (when refilling the bottle ofter use). Also included are three 100 mm long glass rods of 3.5 mm diameter (to clean the mercury surface). According to the manufacturer*, a series of eight star observations (two in each quadrant) deliver the latitude to 2-3" and the time to 0.2 s. |
History & comments |
ca 1963 |
Conservation |
in leather box 145 x 120 x 140 mm. Carrying strap brocken. |
Condition |
Minor paint damage. Mercury dish covered by a glued on metal plate. (The device is not funtional until this metal plate is removed.) |
Remarks |
The box carries the label 'Wild G571 Astrolabe, 1 x Part No. 199898, 1 x Part No. 199899' * see J. B. Mackie, The Elements of Astronomy for Surveyors, 9th ed, 1985, Charles Griffin & Co, High Wycombe, UK The use of the device is discussed on pages 195-199 in R. Roelofs, Astronomy applied to Land Surveying, 1950, N.V. Wed. J. Ahrend & Zoon, Amsterdam |
Dates |
Catalogued in 2008 by JMR. Photo by JMR. |