Société des Lunetiers theodolite
I've obtained this theodolite on a trip to Egypt in 1994. The instrument is of French origin and was used for simple measurements, probably in construction works. As it lacks a vertical scale it might be better to call it a cercle d'alignement (alignment circle).1
The instrument was manufactured by the Société des Lunetiers in its manufacturing plant called La Compasserie.
The sexagesimal divided circle is read down to 1/30th of half a degree or 1 arc minute, similar to the K&E transit in my collection. The reticle has the same lay-out as the transit, but despite being older than it, the cross-hairs are etched rather than made of cobweb.
The telescope can be transited in one direction only by turning it with the objective downwards. The ocular side of the telescope is too long to be transited. The instrument has a sight mounted at a 90 degree angle with the telescope for setting out 90 degree angles in an easy but coarse way.
Thanks to a clamp and drive screw at the bottom of the primary axis the instrument can be used as a repetition theodolite, allowing to measure angles at a higher accuracy.
In overall design the instruments looks quite similar like the mid 19th century Egault level by Secrétan à Paris in my collection.
Notes: Géomusée: Le musée des géomètres-experts de la Région Rhône-Alpes en France.
If you have any questions and/or remarks please let me know.
Surveyor's crosses... Geodetic Sextants... Theodolites... Total Stations... Levels... Standards... Tools... Firms...
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