Spring has officially arrived! Last Fall had some nice nights but it seemed like the only clear nights we had last Winter it was either super cold and windy or there was a blindingly bright Moon. With this in mind I am proposing my arbitrary list of the 10 “best” double stars of Spring and Summer. My reasons for choosing these particular multiple stars was position in the sky (no object below -19° in declination), ease of splitting, and any unusual features such as color or contrast. Some of these are not as famous as others but all are well worth seeking out. So, listed in order of right ascension, here is my list of must see double/multiple stars.
Alpha Ursae Minoris RA 01H Dec+89° Polaris, our “North Star”. The brightness of Polaris can sometimes make it difficult to see the much fainter companion star. Try higher magnifications and perhaps averted vision to see the pair's contrasting yellow and blue colors. A 6-in or larger scope will definitely split Polaris. On a steady night a 3-inch scope will work.
Gamma Leonis RA 10H Dec+20°, “Algeiba”, This is a splendid double star, bright orange and greenish yellow. My favorite view of this double was about 5 years ago at the Green Bank StarQuest in West Virginia. Bill Burgess and I were standing in a light rain and testing out the then new 80mm f/11.25 Planet Hunter refractor. Observing through gaps in the clouds we got a great view of Jupiter. Then Algieba became visible and it was absolutely stunning. Recently I learned there was a planet discovered in this system.
Zeta Ursae Majoris RA 13H Dec +55° Mizar, the Gem of the Big Dipper. Located in the bend of the handle of the Dipper this multiple star system is easy to locate and nearly any optical aid at all will easily spit it. Actually a lot of people with keen vision can split two main components with their naked eyes. Mizar, the brighter one has been found to be a spectroscopic binary as well as the fainter star Alcor. Even a 3-inch scope at 60X will show four stars. This is a favorite of the public during StarWatches.
Upsilon Scorpious, RA 16H Dec -19° This is a quadruple system with stars varying from 4.3 to 8.5 magnitude. Binoculars or a finder scope will spit the two brightest components. Very lovely in a scope at 60x or higher. This is also a great area to just scan around in. Other bright and pretty easy doubles nearby. I like using my 4-in f/4 RFT refractor to study this area of the Scorpion's northern “arm”. This is the most southerly target on the list
Alpha Herculis, RA 17H Dec +14° Rasalgethi, just to the West and a little farther North than a brighter star Rasalhague (in Ophiuchus) this is a fine contrasting pair with a brighter orange-red primary and a fainter companion that is blueish-green. A scope in the 3-4-inch range will split this pair nicely at a little over 100X. The primary also varies between 3rd and 4th magnitude.
Epsilon Scutum RA 18h Dec -15° Two stars of similar magnitude, yellow and deep blue. Very striking. This pair is located in the heart of the Milky Way so it may be a little difficult to locate without setting circles or a Go-To system but worth seeking out.
Epsilon Lyra RA 18H Dec +40° The famous “Double Double”. This system is a couple of degrees east of Vega and is pretty easy to locate. Through binoculars or finder scope the first split can be made. A three inch or larger scope used at magnifications around 60X or highter should split each component again.
Beta Cygni RA 19H Dec +28° Albireo, the “beak of the bird” of Cygnus, the Swan. For a lot of amateur astronomers this is THE best double star visible in our latitudes. Easily split with even small scopes. The bold colors of gold and deep blue (some people see green) are quite vivid and often startles first time visitors at our StarWatches. A real crowd pleaser.
Gamma Delphini RA 20H Dec +16° This beautiful double is the tip of the snout of Delphinus, the dolphin. This somewhat faint constellation can be difficult to find as it lies near to the heart of the Milky Way. It is easy to look at this constellation and imagine a dolphin leaping out of the water.
8 Lacerta RA 22H Dec +39° Lacerta is yet another faint constellation that can be difficult to find but take the time to locate and observe this beautiful quadruple star system. It is well worth the effort to do so.
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About the Author:
Terry Alford has been an avid amateur astronomer since 1979. He is currently a member of two astro clubs: Bays Mountain Astronomy Club (founding member) and Bristol Astronomy Club. Since 2001 Terry has taught Astronomy Labs at East TN State University. His first ATM project was in 1979 and was an equatorial pipe mount for an 8-in reflector. His woodworking shop also turns out toys for grandkids.