As an example of a double star for the viewers, I captured this image of Albireo during a live EAA educational broadcast I did in late July. Such a pretty pair, I decided to post it. Minimal cleanup was done to remove some noise from the glowing halo around the two stars.

Its actually a trinary system! The brighter yellow star, Beta Cyg 1, is actually a pair of closely orbiting stars with a period of about 213 years are of spectral class K3II and B9.5V, while the dimmer blue star visible in the image, Beta Cyg 2, is of spectral class B8Ve. Its not clear whether the wider pair are truly orbiting one another, but they are at similar distances, with the star system being about 430 light years away from us. If the wide pair do orbit each other, their orbit is 100000+ years!

A bit of science-y stuff for the next EAA image I capture of Albireo: As I was preparing the final version of the image, I noticed an intensely red star half way to the top edge of this crop field. None of my processing could have converted a hot pixel to a round star, so I assumed it was real. It is listed in SIMBAD as IRAS 19283+2753 and is indeed red. VERY red. I estimate the difference in red and blue filter magnitudes at several magnitudes. This is estimate is borne out in the G magnitude (a filter used in Gaia astrometry satellite observations centered on the visual band), and 2MASS Two Micron All-Sky Survey IR filter bands J, H and K magnitudes available through SIMBAD:

http://simbad.u-strasbg.fr/simbad/sim-id?Ident=IRAS%2019283%2B2753&NbIdent=1

Given the color, its almost guaranteed to be a carbon star, which exhibit extreme attenuation of all visible red and longer wavelengths due to absorption or shorter wavelengths in the stars bloated carbon rich atmosphere. Essentially a star in a state of permanent sunset!

I think I am going to try some relative photometry in the image to try to get a better measure of the red, green and blue filter magnitudes.

You can see filters for many surveys at SVO. Here are the Gaia and 2MASS filter bandpass plots on the website:

2MASS (Two Micron All-Sky Survey):
http://svo2.cab.inta-csic.es/svo/theory/fps3/index.php?mode=browse&gname=2MASS

Gaia:
http://svo2.cab.inta-csic.es/svo/theory/fps3/index.php?mode=browse&gname=GAIA