Lietz USCGS Survey sextant
A Lietz Company Survey Sextant
Survey sextant used by the US Coast and Geodetic Survey (H843). The instrument was produced by the "The A. Lietz Company" which produced from 1892 to 1947 under that name. This particular instrument does not show in any of their catalogues however for that period. It could well be a special instrument made for the USCGS and not on general sale. The regular sextants have a similar radius but only measure up to 120 degrees where as this one can cover around 145 degrees (quintant).
The instrument differs from other survey sextants (sounding sextants) in the mounting of the mirror telescope; the adjustment of the horizon mirror and the tangent screw. The telescope is mounted using a single screw only and is not fixed in the direction of the horizon mirror. Other sextants have a construction keeping the telescope aligned. The adjustment of the horizon mirror is a typical US construction with two different adjustment screws for side and index error. The construction like this has the advantage of separating the two motions but is much more expensive to make. Finally the instrument has a double tangent screw where most other instruments have a single.
Lietz survey
Data sheet
- Year
- 1892 - 1947
- Serialnumber
- H863
- Type of use
- Survey
- Material
- Brass
- graduation
- deg
- measuring range
- 160 (145)
- Radius limb in mm
- 140
- accuracy
- 0.5'
- fine reading
- vernier (single)
- image direction
- upright
- Size instrument (l x w x h) in m
- 0.19 x 0.22 x 0.12
- weight instrument in kg
- 1.3
- country obtained from
- United States
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A Lietz Company Survey Sextant