NGC 1

Lore & Background

NGC 1 was discovered on 30 September 1861 by Heinrich d'Arrest while testing the 11-inch f/17.5 Merz refractor of the Copenhagen Observatory. This was d'Arrest's first deep-sky discovery, though he was uncertain whether his object was identical to h4 or h5 (both referring to NGC 16). His descriptions, based on four observations, read: 'faint, small, round, 20", no concentration. In a straight line connecting two stars 11 and 14 mag.' Herman Schultz observed NGC 1 three times in 1866 and 1868 with a 9.6-inch refractor at Uppsala; both d'Arrest and Schultz missed the fainter NGC 2, which was later observed as a 'companion' of NGC 1 by Lawrence Parsons. The two galaxies are not physically related: NGC 1 lies at a distance of about 200 million light-years, while NGC 2 is roughly 320 million light-years away.

NGC 1 is a spiral galaxy with a weak nuclear bar and loosely wound arms, classified as SABbc using the Hubble sequence and De Vaucouleurs system. Although the central galaxy is only about 90,000 light-years across, a large, diffuse arm extends eastward, possibly from a past merger. The galaxy is part of the NGC 23 group (also known as LGG 2), which includes at least six other galaxies: NGC 23, NGC 26, UGC 69, UGC 79, UGC 110, and UGC 127. Its nearest major neighbor is UGC 69, a galaxy 80,000 light-years wide, located 4.0 million light-years away.

Reader's Guide

NGC 1 holds a unique place in astronomical cataloging as the first entry in the New General Catalogue, a distinction originally due to its low right ascension in the epoch 1860 coordinate system. Although its coordinates have since shifted and it no longer holds the lowest right ascension among NGC objects, its position as the catalog's opening entry remains fixed. The galaxy's discovery by Heinrich d'Arrest in 1861 marked his first deep-sky find, and the subsequent observations by Herman Schultz and Lawrence Parsons illustrate the early challenges of identifying faint neighboring objects—NGC 2 was missed by the first two observers. The pair forms an optical double but is not physically associated, with NGC 1 being significantly closer. NGC 1 is roughly the size of the Milky Way but two to three times more luminous, with an absolute magnitude of -22.08. Its membership in the NGC 23 group places it within a small cluster of galaxies, and its diffuse eastern arm hints at a possible past merger. The galaxy's distance, derived from its redshift of about 0.015177 and recessional velocity of 4450 km/s, is consistent with redshift-independent estimates, though a conflicting measurement of 2215 km/s is regarded as likely misattributed to another galaxy.

Did You Know?

• NGC 1 was discovered by Heinrich d'Arrest on 30 September 1861 using an 11-inch f/17.5 Merz refractor at the Copenhagen Observatory.
• It is the first object listed in the New General Catalogue because it had the lowest right ascension at the time of the catalog's compilation (epoch 1860).
• NGC 1 and NGC 2 form an optical double but are not physically related; NGC 1 is about 200 million light-years away, while NGC 2 is roughly 320 million light-years distant.
• The galaxy is roughly the same diameter as the Milky Way (140,000 light-years) but is two to three times more luminous.