NGC List of Deep-Sky Objects

Among the tools available to astronomers, the New General Catalogue (NGC) holds a pivotal role. The NGC contains a total of 7,840* unique objects. These objects are a mixture of galaxies, nebulae, star clusters, stars, and other types of deep-sky objects.

*: Although there are 7,840 objects in the NGC, there are a number of multi-part and duplicate objects, which brings the number of unique NGC entries in the database to over 8,300.

The NGC was compiled by Danish astronomer John Louis Emil Dreyer, who was based in Ireland. First published in 1888, it was intended to unify several earlier catalogues, such as the Messier Catalogue and the Herschel Catalogue. It was designed to expand upon and add to these older catalogues, with the inclusion of newer discoveries and more accurate observations made possible by advances in telescope technology in the late 19th century. Dreyer used a consistent system to describe the location, size, brightness, and other characteristics of each object, based on the observations available to him.

Given the limitations of the technology available to Dreyer, some inaccuracies and omissions were inevitable. Several revisions and supplements have been published to address these issues, including the two Index Catalogues (IC), published in the late 19th and early 20th centuries. These catalogues added an additional 5,386 objects, bringing the total to over 13,000 deep-sky objects accessible to amateur and professional astronomers alike.

In the age of digital astronomy and computer-controlled telescopes, the NGC forms the backbone of many digital object databases used by modern go-to telescopes. While the catalogue has been supplemented by more recent discoveries, particularly of more distant or faint objects, it remains a comprehensive guide to the most observed and most remarkable objects in the night sky.