Oxfords leading astronomer was Thomas Hornsby, the Savilian Professor of Astronomy from 1763. He observed the 1769 transit from the Tower of the Bodleian Librarys Old Schools Quadrangle.
Hornsby not only prepared himself for the transit but sought to instruct others. He delivered a series of lectures on the transit in this building, for an audience willing to learn the techniques of mathematical astronomy.
Both the instruments displayed here contributed to Hornsbys transit work. They were not used to view the transit itself but were set up in his private observatory to determine the latitude of Oxford and to regulate the clocks.