The collection includes observation record books for the period 1782-1882, containing observations of stars, planets and comets. There is an observation record book 1793-1796 with a journal of events relating to the setting up and adjustment of clocks and instruments at Armagh Observatory after it was founded in 1790. The observation records continue into the 20th century and are supplemented by various miscellaneous observations and related documents. These include a catalogue of 153 of the principal fixed stars etc for the year 1760 and the six following years with a general index, some papers relating to the solar eclipse of 28 November 1807 by Hamilton and a book of manuscript observations and notes by W. Davenport, 1816-1819 containing a copy of Troughton's directions for adjustment of the Equatorial. Dreyer's astronomical observatios made with the 10-inch Grubb refractor at Armagh Observatory , 1885-1914, also form part of this collection.
Series of sytematic transit instrument and mural circle observations made from 1828 - 1882. Dreyer's astronomical observations made with the 10-inch Grubb refractor at Armagh Observatory , 1885-1914 also form part of this collection.
15 volumes of mural circle observations 1796 - 1882. c.50 volumes of meteorological records 1794 - present day.