« Hillary's Talking Points Ventriloquist Doll, Susan Rice, "Definitely" Being Promoted to National Security Adviser | Main | Overnight Open Thread (5-15-2013) »

CAC's Spaced-Out Challenge: Seeing Double

After weeks of focusing on objects that lower in the sky (and probably harder for those of you with typical backyards), time to go higher. This week, the moon hangs in the sky later and later, making fainter deep sky objects harder to spot in the process. So, we're going for steady skies and tempting doubles for a pair of challenges rising late in the evening/early in the morning that you can spot practically anywhere.

The rules for double stars are a bit different than other deep space objects we have attempted so far. Double stars, with few exceptions, do not suffer from light pollution or even a full moon.
1- They do require steady skies and good transparency, as many are impossible to split otherwise in even the best telescopes. A helpful weather predictor (more accurate than any I've found, at least) is Intellicast's Sky Watch here.
2- If you have a large reflector, give it time to cool down at least an hour before observing. Turbulence from outside/inside air will obscure your view.
3- Make sure your scope is properly collimated, because poor alignment will make either of these challenges pointless.
4- Protect your night vision as best as possible (see the Sunday reminder on Omega Centauri for some tips), but losing it from a stray light won't hurt you here. For particularly bright and close doubles, a variable filter (moon filter) will help cut down the brightness from the primary star, teasing out its companion.

Challenge #1: Alpha Hercules
I personally love double stars with contrasting colors, and alpha Her's red-green/blue combo is one of the more striking:

Finding it from light polluted skies is initially tricky but with your eyes adjusted enough the star-hop is relatively simple, then just crank up your power:

Challenge #2: The Double Double in Lyra

Near one of our ringed challenges from two weeks ago, we find another interesting sight in the harp high over our heads, the Double Double, epsilon Lyrae:

This is a very, very challenging double-within-a-double, so it may take several attempts to split it. But at least it's easy to find, situated near the very bright blue star, Vega:

Bonus Object!
You may notice a fuzzy star in Hercules after your eyes have adjusted to the semi-darkness:

Aim your binoculars or scope at it for a bonus treat- the great globular cluster in Hercules:

Nowhere near the size of Omega Centauri, this great cluster (Messier 13) is more easily resolved into individual stars from our latitude than the giant from the South. Intriguing in binoculars, it gets it's real glory through low-to-mid-power in a telescope, but it like the doubles shines through, light pollution be damned. M13 was also the target of a team of astronomers and theorists (including Frank Drake and Carl Sagan) for a radio message sent out from the Arecibo radio telescope in the 1970s:

Whether or not a civilization would actually be on the receiving end depends on your views on the hardiness of life. With globular clusters consisting of hundreds of thousands of stars tightly packed together, I think the constant disturbances by nearby stars of local systems' oort clouds, would fling one-too-many life-ending rocks inwards towards any fledgling lifeforms, but at least the graphics are cool for early seventies standards.

For a cheap moon filter, I can suggest the Orion variable, available here on Ace's Amazon store. Next week, we're getting ready for a triple-planet treat.
Remember the light-pollution-be-damned target list here, clear skies to you and keep looking up!