These last nights, though brightened by the full moon, have been clear, cool, and relatively free of bugs and so as tends to be the case this time of year I find myself drawn to spending more time under the night sky.
Moonlit nights are a good time for observing double stars as the brightened sky does little to diminish their beauty. Out I went with my 60mm scope and copy of Double Stars for Small Telescopes to explore Cygnus.
With Deneb (Alpha Cygni) shining bright near the zenith I pointed my telescope roughly towards the tail of the swan and looked through the 6×30 finder. I was surprised to see what appeared to be a wide double star with a striking color contrast.
Looking at my Pocket Sky Atlas I determined I was looking in the area of Omnicron Cygni, which actually fits in the same ~7° finder field as Deneb. Omnicron Cygni has two components, Omnicron1 and Omnicron2, both of which appear reddish-orange through the finder.
O1 Cygni was the double star that first caught my attention. Its companion is 30 Cygni which shines cool blue. Taking a closer look through the finder another dim blue spark is visible closer to O1. Yes, Omnicron1 is actually a triple star.
All of this is visible through the 6×30 finder but how is the view through a 60mm telescope? First, the star colors are much more apparent. Looking at O1 at ~40x, its warm reddish color stands out, while 30 Cygni appears bluish-white, and O1‘s dimmer companion appears blue.
While this power brings out the colors nicely, the star grouping actually looks a bit nicer at lower magnifications. I really enjoy it around 14x and I’ll make a point to revisit it in my 16×50 binoculars.
Omnicron2 Cygni is worth a look as well. At low powers O2 Cygni appears as if it is part of a small, loose cluster; its shape reminded me of a kite.
I spent time looking at a few other doubles in the area, including Albireo (Beta Cygni). Albireo is considered a wide double and though barely splits in a 6-8x finder its golden amber and blue components are a beautiful sight at fairly low powers in a scope.
While Omnicron Cygni doesn’t match Albeiro for pure beauty, its visual complexity gives it a bit more depth and I’ll be returning to it often. For a great visual overview of Omnicron Cygni, see Jerry Lodriguss’s photographs of the grouping.
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