Discovered by Caroline Herschel in 1783, NGC7789 is not only one of the richest open star clusters you’re likely to observe, but also one of the oldest.
One of the richest concentrations of stars in the northern sky exists in the big open cluster NGC 7789 in Cassiopeia, a great sight for binoculars or a small scope. Credit: Alan Dyer
When you’re gazing at objects in the northern sky, do not forget to look at one of the richest open star clusters you’ll ever see. NGC 7789 in Cassiopeia is particularly notable for its huge mass of relatively faint stars, all set in a rich Milky Way star field, which makes for a great scene in binoculars or a small telescope.
NGC 7789 was discovered by Caroline Herschel in 1783, and it’s sometimes called “Caroline’s Haystack,” “Caroline’s Rose,” or the “White Rose Cluster.”
This object is a relatively old open cluster at 1.7 billion years. It lies a healthy 7,600 light-years away.
It’s hard to find a more spread-out cluster as richly populated as this one in many places in the sky. NGC 7789 has a combined magnitude of 6.7 and it spreads over 16’, half the diameter of the Full Moon.
This great cluster contains about 6,600 solar masses of material, with a stellar membership of approximately 1,000 Suns.
