Reversible Transit Circle
6 inch Telescope (15 cm)
This telescope was for a long time the only active transit instrument in the Southern Hemisphere.
- Designed by David Gill. Became the model for most transit circles made since.
- This telescope was in continuous use for observing the planets and selected stars to provide a fundamental system of star positions which is the observational basis of dynamic astronomy, accurate geodesy and of the determination of stellar motions.
- Instrument was the main source for the southern portion of the Fundamental Katalog (FK4)
The telescope was designed by Sir David Gill and installed in 1905. It was a phenomenal instrument and became the example of how to design a transit circle. The telescope was modernised in the post World War Two period by installing cameras to photograph the declination circles, as well as a host of electronic instrumentation. The instrument remained in use until satelites such as Hipparcos and Gaia came into use rendering the instrument obsolete. [conversation with Ian Glass, Nov 2020, cdc]
S.A.A.O. (used to be the Cape Observatory)
The building is in serious need of repair. The telescope itself requires a service. The supporting instruments such as cameras to measure the declination will be a great problem to overhaul.
Aperture: 6 inch (15.24 cm)
Manufacturer: Troughton and Simms. [Laing, p.13.]
- The instrument as designed by Gill was completed in 1905 [Laing, p.29.]
- The instrument was modernised with electronics and cameras in the 1950’s and 60’s. [Laing, p.17; p. 9.]
- Laing, J.D. (ed.), The Royal Observatory at the Cape of Good Hope 1820 – 1970 Sesquicentennial Offerings.
- Collins, P. & Moore, P.; Astronomy in Southern Africa, p79.
- Laing, J.D. (ed.), The Royal Observatory at the Cape of Good Hope 1820 – 1970 Sesquicentennial Offerings, p.13; p.17; p.29.
- Smits, P., A Brief History of Astronomy in Southern Africa. (Unpublished)