Micrometer-microscope by Troughton and Simms

Micrometer-microscope by Troughton & Simms. 1899.
The Royal Society provided 70 pounds towards purchasing this measuring machine. A survey of the positions of all stars and other objects within 25 arc minutes of the centre of the spiral galaxy in Triangulum, Messier 33, was conducted using photographic plates exposed by Isaac Roberts (see Proc. Roy. Irish Acad., 25A, 1904).

Last Revised: 2009 November 5th