Certificate to Sir Geroge Biddell Airy, 1891.

Certificate, in German, from 'Der Vorstand der Astronomischen Gesellschaft' (the Board of the Astronomical Society) to George Airy, expressing admiration and thanks for his life's work. There is no date on the certiciate but it mentions his retirement from the post of Astronomer Royal ten years prior, and so can be dated to 1891, when Airy reached 90 years of age.

Administrative / biographical background
Sir George Biddell Airy was a mathematician and astronomer. He was a Professor at Cambridge University before being appointed the Astronomer Royal in 1835, a position he held for 46 years until his retirement in 1881. His achievements include the Airy Transit Circle telescope which defined the Prime Meridian at the Royal Observatory Greenwich, on which GMT is based.