de Koningh vernier survey sextant
Vernier survey sextant by G. de Koningh, Amsterdam.
Product details: de Koningh vernier survey sextant | de Koningh | Reflecting circle | Survey | Material: Brass
Three ring survey sextant using a vernier and a silver inlaid scale. The index mirror uses a double set of capstan screws for adjustment rather than the more usual single capstan screw. The vernier scale is hard to read although the microscope definitely helps. The objective is low power with a high light intensity. The instrument can measure above 170 degrees making this technically a reflecting circle.
Based on its serial compared to other instruments it is probably from somewhere in the late 1930's or early 1940's. The Naval Museum in Den Helder holds three similar instruments with serials 4432, 4433 and 4575. Unfortunately these are not numbered. A similar instrument from the TU Delft - Geodetic Laboratory has an older serial (5056) indicating the instrument has been produced to somewhere in the late 1940's.
de Koningh vernier
Data sheet
- Serialnumber
- 4440
- Type of use
- Survey
- Material
- Brass
- graduation
- deg
- measuring range
- 170 (150)
- Radius limb in mm
- 160
- accuracy
- 0.5'
- fine reading
- vernier (single)
- image direction
- upright
- Size instrument (l x w x h) in m
- 0.23 x 0.30 x 0.13
- weight instrument in kg
- 1.5
- country obtained from
- Netherlands
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Vernier survey sextant by G. de Koningh, Amsterdam.
Product details: de Koningh vernier survey sextant | de Koningh | Reflecting circle | Survey | Material: Brass