If you subscribe to Sky and Telescope, keep your eyes open for the article More of My Favorite Double Stars by James Mullaney in the September 2006 issue. I was invited to submit a few double star sketches to help illustrate the article. The author lists a couple dozen autumn doubles for your viewing enjoyment. Eight in that list are discussed in greater detail in the article. It just so happened that I had already sketched 5 of those, and I had enough time to observe and sketch 2 more of them. The only one I couldn't submit was Delta Cephei which was still simmering in the dawn twilight at the time.
As you might have guessed, I'm pretty excited that the author and/or editor chose to use sketches to supplement the article. I imagine part of that choice was due to the fact that it is just plain hard to find photography of specific doubles. They are out there; just not in the same abundance as other deep sky objects.
Following are the sketches that appear in the article:
Personally, I'd love to see sketches used more often to illustrate articles about visual astronomy. Not to the exclusion of astro photography of course. Because visual observers benefit from knowing more objectively what features to search for in an object. But I really value a sketch of an object for showing what a human eyeball and the not-quite-perfect human brain behind it are capable of discerning.
With double star sketches, that eye-brain interaction yields some interesting results when it comes to color assessment. Not only will optics, atmospheric conditions and local light pollution have an effect on color impressions in a double, but so will the physiology of an individual observer's eyes, and the psychological effects of their mind interpreting those little pinpricks of subtle color in close proximity.
I had some anxiety about how my personal interpretation of those colors would be received. Before submitting the sketches, I searched the web for other observers impressions of each double to see if I could soothe my nerves. I found that my assessment was in the norm for several of them. But there were a couple that definitely hit the fringe...such as Eta Cassiopeiae and Gamma Arietis. Eta Cass is described by most observers as a yellow primary and a purple/orange/red secondary. But I saw key-lime-pie green and orange. I remember that double vividly, because as I was observing it, I was fascinated that the primary exhibited such an unusual and obviously impossible color. But I couldn't shake the impression each time I returned to the eyepiece. So that's how I colored the sketch.
For a hobby that is built on a foundation of scientific interest, I'm sure the vagaries of visual observations are vexing to some amateur astronomers. But that same variation from observer to observer and even from observation to observation for the same observer, is a facet of the hobby that I find very enjoyable.
If you have any comments or criticisms about the sketches, I would love to hear them. You can post them here, or email me at the address shown at the top of the page.