Wild Heerbrugg T1a
T1 with automatic levelling on the vertical circle.
Product details: Wild Heerbrugg T1a | Wild Heerbrugg | Optical theodolite | Survey | Material: Brass
This T1a is a later development of the T1 and has an automatic compensator for the vertical circle. If the instrument is level to within a certain degree, the automatic compensator will level the vertical circle. One of my two instruments arrived in a non-working state but I managed to get it working again. That is, it can be moved mechanically again and it can be read optically. However it must have sustained a heavy shock (falling) at some point in time and is no longer true. The other does move but requires cleaning of the vertical scale. The two models differ slightly in the design of the telescope eyepiece construction as well as in the tribrach. Where the 1959 uses a fully circular tribach with a screwing type as the previous NT1 did, the 1961 version uses the modern type tribrach with a slot and quick release.
More information / other collections:
T1a
Data sheet
- Year
- 1959 | 1961
- Serialnumber
- 77108 | 89093
- Type of use
- Survey
- Material
- Brass
- graduation
- deg
- diameter scale in mm
- ca 75 mm
- accuracy
- 20"
- fine reading
- scale micrometer
- image direction
- inverted
- magnification
- 30
- field of view @1000m in m
- 29
- Size instrument (l x w x h) in m
- 0.15 x 0.13 x 0.25
- weight instrument in kg
- 5
- Size case (Ø x h) in m
- 0.17 x 0.37
- weight case & in kg
- 2.4
- country obtained from
- Netherlands
United Kingdom
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T1 with automatic levelling on the vertical circle.
Product details: Wild Heerbrugg T1a | Wild Heerbrugg | Optical theodolite | Survey | Material: Brass