Cluster of clusters

Pierre Moutounet-Cartan
Feb 24
2 min read

#NGC1746 / #NGC1750 / #NGC1758 and #PMC19

About this object

Nestled in the constellation Taurus, the trio of NGC 1746, NGC 1750, and NGC 1758 offers amateur astronomers a fascinating glimpse into the complexities of stellar groupings. NGC 1746, once thought to be an open cluster, is now considered a likely asterism—a chance alignment of stars spanning about 40 arcminutes. Its sparse and scattered appearance makes it an intriguing target for wide-field telescopes. Nearby, NGC 1750 is a true open cluster, stretching 20 arcminutes across the sky, with an estimated age of 150–200 million years. This cluster is home to several dozen stars, many of which are still burning hydrogen on the main sequence. In contrast, NGC 1758 is a smaller, denser cluster, only 10 arcminutes in size, and much older at around 800 million years. Its stars have evolved significantly, with many entering the red giant phase, giving the cluster a warmer, redder hue. Despite their close proximity in the sky, detailed studies of stellar motion and distance reveal that NGC 1750 and NGC 1758 are unrelated, and NGC 1746 is likely just a random grouping of stars. Observing these clusters together provides a unique opportunity to compare the characteristics of true clusters and asterisms, making this region a rewarding target for stargazers.

There is a whole research around the classification of starts to their respective overlapping clusters in this region of the sky, e.g. Tian, K.P. et al (1998).