Trade card for the creator of the Royal Observatory’s eight-foot telescope
By BIRD, John, 1748
John Bird Mathematical Instrument Maker.
- Author: BIRD, John
- Publication place: London
- Publisher: at the Sea Quadrant, near the new-Exchange Buildings in the Strand
- Publication date: from 1748
- Physical description: Engraved trade card.
- Dimensions: 150 by 95mm. (6 by 3.75 inches).
- Inventory reference: 17851
From about 1746, Bird supplied the Royal Observatory with a brass mural quadrant of eight-foot radius and a transit instrument of eight-foot focal length. With these instruments James Bradley, the Astronomer Royal, made a series of observations of the sun, moon, planets, and fixed stars, which was carried on by others after his death. When, in 1776 the Greenwich observations for 1765 to 1774 were published, Bird’s instruments were still in use and their accuracy so exact that “the place of any heavenly body may be always found by them within ten seconds of a degree, both in Longitude and Latitude, and generally much nearer” (Nevil Maskelyne).
- BM Heal 105.10<br />