Back to: Weekend Sky Report
May 03, 2019
When amateur astronomers think of Hercules, they usually think of Messier 13, the brilliant and relatively bright globular cluster near Hercules’ right hip. It’s one you can just about see with the naked eye under perfect conditions… but after you find that one, or maybe instead of looking for that one, use bright Vega and the star Eltanin (el-TAY-nin) to find the slightly dimmer and more distant Messier 92.
M92 is one of the galaxy’s oldest globular clusters. Research published in 2007 suggests it began forming shortly after the Big Bang—more than 13 billion years ago. Globulars take a long time to form, so most of them are some of the oldest structures in the universe, but not many come even close to the age of M92.
To find it, look to the northeast. It’s probably best to look around or after 10pm when bright Vega is high enough above the horizon. Once you find Vega, look above and to the left of Vega for the dimmer, but still prominent orange-white Eltanin (el-TAY-nin). Now, imagine those two stars being part of an acute triangle with Vega at a sharp point. The point opposite Eltanin lies at about the same distance and angle from Vega, but to the right. Point your telescope at that spot and slowly scan upward until you see what looks like a dim, fuzzy star. That’s Messier 92.
Now, despite its proximity to brilliant M13, M92 is still one of the brighter globular clusters in the night sky. So just about any telescope should be able to spot it. And again, when you find it, you’ll be looking at something that began forming just after the dawn of time itself.