Early C Plath Drei Kreiss survey sextant
C.Plath early survey sextant.
This C.Plath survey sextant was a very special find. Unfortunately it does not have its box anymore and has been stripped of most of its paint but even without it, it is a special addition to my collection. The instrument has the 'old fashioned' C.Plath Hamburg name in flowing script as well as a serial number of 3735 on the arc with an additional number of 300 on the back. The scale also shows the 'S' for inspection by the Deutsche Seewarte but does not have the traditional C.Plath 'Stick' figure logo on it. Based on information the serial provides a data anywhere between 1899 and 1910. As production in 1910 was up to around 320 units / year but untill 1901 only around 30 units per year, the most probable date is somewhere around 1905.
What makes this sextant special is the construction of the tangent screw and clamping mechanism. Rather than the later models with a single screw using a spring to unlatch it from the arc, this one has a quick release construction besides the tangent screw. The quick release mechanism is operated by rotating the lever pointing towards the observer. The (endless) tangent screw can then be used for fine adjustments.
Other sources:
Sextantbook This is the navigation version of the same instrument.
drie kreiss survey
Data sheet
- Year
- 1905
- Serialnumber
- 3735
- Material
- Brass
- graduation
- deg
- measuring range
- 150 (135)
- Radius limb in mm
- 180
- accuracy
- 0.5"
- fine reading
- vernier (single)
- image direction
- upright
- Size instrument (l x w x h) in m
- 0.24 x 0.27 x 0.13
- weight instrument in kg
- 1.4
- country obtained from
- United Kingdom
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C.Plath early survey sextant.