This stellar cluster is a relatively loose collection of around 60 visible stars scattered over a wide area, making it an ideal target for wide-field astrophotography. NGC 752 is notably older than most open clusters and lacks bright, blue, massive stars. Its sparse structure gives astrophotographers the chance to capture both the rich cluster stars and the dark background of the Milky Way. The cluster stands out particularly well in dark skies, highlighting the contrast between the aging cluster and its cosmic surroundings.
Names and Catalog numbers
- Caldwell 28
- NGC 752
- Melotte 12
Position and the cosmic neighborhood
NGC 752 lies approximately 4° to 5° south of Gamma Andromedae in the constellation Andromeda, placing it well within the northern sky and making it particularly accessible from mid-northern latitudes. Its proximity to several background galaxies also adds interest for deep-sky astrophotographers, who may capture some of these faint galaxies in wide-field images. With the rich stellar fields of Andromeda as a backdrop, the cluster appears as a loose scattering of stars set against the Milky Way, establishing it as an appealing and distinctive night-sky feature.
Nice to Know
- NGC 752 is considered one of the oldest known open clusters, with an estimated age exceeding one billion years.
- The cluster is large and sparse, spanning a wide area of the sky and best framed with lenses or telescopes offering a wider field of view.
- The absence of bright, hot blue stars is due to its age; most massive members have already evolved off the main sequence.
- NGC 752 is bright enough to be visible with binoculars under dark skies, though its scattered, sparse appearance may be subtle to the naked eye.
Brightnes, distance and size
NGC 752 has an apparent brightness of around magnitude 5.7, making it visible to the unaided eye in very dark locations, but it is easily identified in binoculars or wide-field telescopes. Its estimated distance from Earth ranges between roughly 1,300 to 1,400 light-years. The cluster’s true size is about 18 light-years across, while its apparent size spans a generous 75 arcminutes—more than twice the apparent diameter of the full moon—making it a striking and rewarding wide-field astrophotographic target.
