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