Star Clusters

Star clusters, both open and globular, generally show up well in washed-out skies. There are lots of relatively bright clusters, and their stellar nature allows you to use magnification to darken the background and enhance the contrast. You won’t catch quite as many stars as you would in dark skies, but there is still plenty to see: clusters that look spectacular in dark skies still look quite stunning even with light pollution. The brighter globular clusters do particularly well in washed-out skies.

When observing open clusters focus on the colors and patterns because these are features that generally come through undiminished under washed-out skies. For example, look for the red stars in the Double Cluster (NGC 884/869), NGC 457, M47, or M6. Or admire the extreme blueness of the stars in the Pleiades.

Other clusters have particularly unique patterns. Do you see an owl or a jet fighter in NGC 457? A butterfly or a starfish in M93? Can you see Indiana Jones’ whip in NGC 7243, or the Greek letter π in M38? Do you see the infamous wild duck in M11? Or how about the “hole” in M26?

Bright globular clusters (such as the Messier globulars) also come through well under light pollution. In fact, they are some of the best deep sky objects for washed-out astronomers. Whenever my neighbors ask to look through my scope, I point it at the most convenient globular and never fail to elicit a “wow!” While light pollution will mask the fainter stars, with sufficient magnification the brighter globulars will usually resolve nicely. However, in washed-out skies it does take a bit more aperture to achieve resolution. For example, in dark skies my 4.25 inch (108mm) reflector shows some resolution of M13. With light pollution, only on the very best nights can the 4.25 inch even begin to show any resolution.