NGC 752, cataloged as Caldwell 28 and Melotte 12, is a large and loosely scattered open star cluster in Andromeda that spans a full 1.0° (58′) of sky, making it an ideal subject for wide-field astrophotography. Its generous angular size means that short focal lengths and camera lenses in the 200–400 mm range frame it far better than long telescopes, which would overflow the cluster beyond the sensor edges. Because the cluster’s brighter members are well separated and not overwhelmingly dense, careful exposure balancing keeps individual stars crisp and avoids a blown-out core. Its position in a rich section of the northern Milky Way region also rewards imagers with a colorful sprinkling of background field stars framing the cluster.
Names and Catalog numbers
- C 28 (Caldwell 28)
- NGC 752
- Mel 12 (Melotte 12)
Position and the cosmic neighborhood
NGC 752 sits in the constellation Andromeda at a right ascension of 01h 56m 53.5s and a declination of +37° 47′ 38″, placing it high in northern autumn skies where it stays well clear of the horizon murk for most northern observers. Its location makes it a convenient companion target during imaging sessions aimed at Andromeda’s more famous showpieces, and the surrounding star field offers a pleasing density of foreground and background stars to enrich a wide-field composition. With its measured physical diameter of about 25 light-years, the cluster presents a genuinely large but comfortable target that pairs naturally with nearby double stars and asterisms in the same frame.
Nice to Know
- At a full 1.0° (58′) across, NGC 752 covers roughly twice the apparent width of the full Moon, so it demands a wide-field imaging setup rather than a long telescope.
- Lying about 1,490 light-years away, it is a relatively nearby cluster, which contributes to its large apparent size and well-resolved individual stars.
- Its true physical diameter of around 25 light-years makes it a genuinely extended stellar grouping rather than a compact knot.
- The cluster carries three catalog identities — Caldwell 28, Melotte 12, and NGC 752 — reflecting its long-standing appeal to observers across multiple deep-sky catalogs.
Brightness, distance and size
It lies about 1,490 light-years from Earth and spans roughly 25 light-years across. On the sky it appears about 1.0° (58′) in size.
