The quest for clusters and star clouds

As September rolls in, so too do darker nights. The sun starts setting earlier, crossing the celestial equator and reaching autumnal equinox on September 22. Here in Ontario, the summer weather hasn’t left completely, but the cooler systems mean we should hopefully see some beautifully clear nights as the light fades. 

Solar System

The planets are relatively quiet this month. Saturn and Jupiter continue their fellowship, strolling through Capricorn together pretty much all night through September. Just like last month, if you have a clear view of the southwest on September 9, look for bright Venus near a thin crescent Moon as the sun sets (if you miss it, don’t worry — the pair will meet again on October 9). Unfortunately, this month, Mercury and Mars will be setting rather too close to the sun to get a good look at them. 

Deep sky

The Moon reaches its new phase on September 7. It will start setting relatively early during the week afterward, leaving you with a good window for deep-sky observing of late summer constellations. While Scorpius is moving too close to the sun to see, you can still take a few last glimpses of Sagittarius and its gems before it, too, heads out of view for the winter.

After sunset, you’ll find Sagittarius in the south. It looks like a teapot. The teapot’s “spout” points to the Large Sagittarius Star Cloud, while the “lid” is around many relatively bright, easy-to-find objects like the Lagoon Nebula, the Small Sagittarius Star Cloud, and oodles of open and globular clusters. 

Clusters are a great introduction to deep-sky objects. Open clusters are beautiful groups of young stars that burn hot and fast, loosely bound together. Messier 23 is one, and it’s thought to be about 330 million years old. 

Globular clusters, on the other hand, are more calm and sedate, made of very old stars that burn slowly and are tightly bound together by gravity. Messier 54 is thought to be around 13 billion years old, while Messier 28 is estimated to be about 12 billion years old. If you find one of these globular clusters – they look like round, grey, hazy spots through your telescope or binoculars – just think for a second about the fact that you’re probably looking at the oldest thing you’ve ever seen.