Telescope length is 22 racked in, adjustable with the rack and pinion wheel. I believe the small eyepiece lens cover is a replacement. The objective glass measures just over 1.5 diameter, is original and damage free, giving an excellent clear inverted image when viewed by the user.
The two'A' frame supports are held in place with the circular base ring which has three levelling screws (diameter 12.5). This fine instrument is the former property of the late Sir Patrick Moore CBE HonFRA FRAS (1923 - 2012) who was President of the British Astronomical Association, co-founder of the Society of Popular Astonomy, author of seventy books on astronomy, and presenter of the world's longest running television series with the same original presenter, BBC's'The Sky at Night'. He became known as a specialist in Moon observation and for creating the Caldwell catalogue - an astronomical catalogue of 109 star clusters, nebulae and galaxies for observation by amateur astronomers. The last picture shows Sir Patrick Moore with the transit.
The primary function of a transit telescope was to observe the movement of'clock stars' - stars whose position was accurately known. The movement of known stars could be logged and comets observed against background stars, allowing astronomers to observe the Sun, Moon, planets & minor planets & other stars to improve knowledge of their positions and proper motion. Troughton & Simms worked from 1826. Theodolite / transit / telescope. The item "A very rare reversible Transit / Theodolite Troughton & Simms" is in sale since Sunday, October 28, 2018.This item is in the category "Antiques\Science/Medicine\Scientific Instruments". The seller is "marl727" and is located in Blackpool. This item can be shipped to North, South, or Latin America, all countries in Europe, Australia.