At the request of Governor Thomas Brisbane, James Dunlop came to New South Wales from England in 1821 to assist with establishing an observatory at Parramatta. Encouraged by Brisbane, Dunlop developed his interest in astronomy, and after observing the southern skies he produced A Catalogue of Nebulae and Clusters of Stars in the Southern Hemisphere which was published in 1828.

Appointed superintendent of the Parramatta Observatory in 1835, Dunlop continued to make observations of asteroids, comets and planets. He received a gold medal for his catalogues of stars and nebulae from the Royal Astronomical Society in 1828.