NGC 4609

The open cluster NGC 4609, also Caldwell 98, stands out from the dark Coalsack in the constellation Crux. It is small, and contains around 5 stars of magnitude 9. Binoculars do not show much, and even an 80mm telescope will only show about 20 stars.

NGC 4609 is actually located behind the Coalsack, at a distance of 1320 parsecs. It is about 6 million years old. The spread of stars around the main sequence is larger than in other clusters; however, this may be caused by to the absorbing material of the Coalsack.