13 February

Dreyer was the Danish astronomer who compiled the New General Catalogue of Nebulae and Clusters of Stars (NGC) in 1888.

When he became Director of the Armagh Observatory in 1882, financially it was destitute, with no prospect of replacing its aging instruments.

Though Dreyer obtained a new telescope, the lack of funding for an assistant precluded him from a continuation of astronomical observations.

Instead he concentrated on the compilation of observations made earlier. In the NGC he listed 7840 objects, and in its supplements (1895, 1908) he added a further 5386 objects. It remains one of the standard reference catalogues today. He died 14 September 1926.