Image Credit & Copyright: Me.
Before winter creeps up on us and steals away the great asterism of the Summer Triangle get out there and view some of the gems in the hot Northern hemisphere nights.
This image I actually took this past week from my bright New Hampshire skies. You’d be surprised to know that it’s actually very difficult to find very dark skies even here in the sticks. You have to travel pretty far north to get into dark sky country and even then, if you’re doing widefield astrophotography of say, the Milky Way, you will still inherently have light pollution on your horizons. Dark yes; very dark, no! Where I am in southern NH is actually still in the “Reed Zone” from Boston.
Many of you may already know this object as the beak of Cygnus the Swan. Its name is Albireo or Beta Cygni and in my opinion it’s the most beautiful double star system known. Its color contrast through a telescope alone keeps you coming back for views night after night.
One note here is that you probably won’t be able to split this double without the aid of a small telescope. I haven’t tried lately but I’m not even sure you can cut it in small binoculars. To find it, locate the close partners of Lyra and Cygnus. Lyra hosts the bright star Vega while Cygnus takes on the shape of a large cross, thus it also takes on the name of the asterism “Northern Cross.”
The top four stars in the cross are headed by Deneb and are easily seen. Deneb is the tail in Cygnus but the top of the “Northern Cross.” Now follow the long portion of the cross down from the star, Sadr which is the intersection star, just over twice as far as you have to in order to get to Deneb in the opposite direction. You have found Albireo!
Many double star systems that we see are line of sight doubles whose stars are in chance alignment and not actually in orbit around one another. Albireo, it’s believed, is a true multiple star system whose constituents are gravitationally bound, but remember these blue and gold gems roughly 380 light years away, are 60 times the diameter of our solar system apart from each other and take as long as 100,000 years to complete an orbit around each other so don’t expect to see much change in your lifetime.
The brighter 3rd magnitude golden star (Albireo A) outshines its 5th magnitude blue partner (Albireo B) when you view it naked eye but when you aim a telescope in that direction the pair spaced 35” arcseconds apart really come to life and amaze. The lower the power you use the closer the pair will look and possibly give you a greater color contrast but it really shouldn’t matter. If you’re having trouble seeing the colors try taking them out of focus slightly.
Something you won’t see with a telescope but in 1976 it was detected through speckle interferometry is that the brighter golden partner is a binary into itself, making this system at least a three star system.
As for the image, it is a single 10 second shot at ISO 3200. I overexposed it slightly to bring out some of the background stars. If I really took my time and processed this image I’d likely remove these two stars and replace them with a more pinpoint pair to lie in the star field. Perhaps even boost up the color slightly and give them some diffraction spikes.
Anyway, hope you like the image and if you want to see a larger size shot hit the blog DanSpace77.com. If I keep taking images I’m going to need a watermark I think. Feel free to use and abuse this image all you want, just give me credit and do not label it with any markings of your own.