Carl Zeiss “Theo 101” theodolite and tacheometer. Used for measuring horizontal and vertical angles in land surveying and for setting out works.
This theodolite is compatible with the Zeiss “Karti” plane table (see https://ice-museum-scotland.hw.ac.uk/product/2019-035/).
Information from Zeiss Archive [translated from German]
The second theodolite Theo 010 with mirror lens telescope with large aperture and centric eyepiece, with practically complete elimination of the secondary spectrum, can be used for triangulations up to and including the second order, but also for precision polygoning above and below ground, as well as for astronomical follow-up measurements.