Melotte 28 / Collinder 57 is a loose and irregularly scattered open cluster of approximately 75 stars spanning 42 minutes of arc located in Taurus between the horns of the bull. Thus the "cluster" spans 1.5 times the diameter of the full moon and is visible to the naked eye on clear nights with dark skies. For reference, east is up on this image and north is to the right.

The entire cluster is often designated NGC 1746, and classified as Trumpler Type III 2 p open cluster, but a detailed study of its constituent stars by Galadi-Enrquez and others (1998) concluded that it is a chance optical alignment that partially superimposes two separate open clusters. The nearer of the two open clusters is designated NGC 1750, and is distant 630 parsecs or 2050 light years. It lies on the western, lower side of the conglomeration and is comprised of 79 members brighter than magnitude 15. It is visible on the image as the slightly brighter, and somewhat bluer, grouping of stars below the arc of four bright yellowish-orange field stars. Approximately 10 arc minutes in size, it shines with an integrated magnitude of 6.8v, and has an age estimated at 200 + 50 million years.

In contrast, open cluster NGC 1758 is more distant at 760 parsecs or 2480 light years, and is also older with an estimated age of 400 + 100 million years. It lies on the eastern, upper side of the conglomeration, and is visible on the image as the fainter, whiteish stars just below the apex of the four bright yellowish-orange field stars. With only 57 members brighter than magnitude 15 in a radius of approximately 7 arc minutes, as expected, it shines with an integrated magnitude of only 8.5v.

Galadi-Enrquez et al. concluded that NGC 1746 does not correspond to any existing object, and that NGC 1750 and NGC 1758 are not gravitationally bound entities, but are rather a chance optical superposition of two visually overlapping open clusters.

Field of view is 2 degrees 18 minutes by 1 degree 31 minutes.