Disc planisphere made by Jeremiah Sisson, London, England, 1750-1775. Signed 'J. Sisson London'.

This planisphere was made by Jeremiah Sisson. The outer ring carries the calendar, the next ring the time, and the inner disc carries information about certain bright stars. The index had a cursor which was used to align a star with the date and the time of transit, or passage across the meridian. The times of the transits of all the other stars marked were then shown. Jeremiah Sisson (active 1749-1783) was a mathematical instrument maker based on the Strand in London. He took over the business of his father, Jonathan Sisson, but was declared bankrupt in 1775.