CISTO Blog: Free-floating cosmic balloon

An 80Q jpg version of the "redo" at processing, reposted to Asterisk.

CITSO Blog: Free-floating Cosmic Balloon

NGC 7635 (Bubble Nebula) in Cassiopeia

July 2 - September 4 2011

Click the image for the high resolution version!

NGC 7635 (Bubble Nebula) in Cassiopeia.

Imaged July 2 to September 4 2011, 11+ hours total.

L=280 minutes (1x1), R=110m, G=100m, B=100m, Ha=90m (2x2). Subs=10m.

Telescope=PlaneWave CDK17, Camera=SBIG STL-4020M, Mount=Paramount ME.
PlaneWave focal reducer (f/4.5). Baader filters.

Frames acquired with TheSky X, MaxIm DL, and Focusmax.
Processed with PixInsight and CCDInspector.

The summer of 2011 was a very special one for my family and me, the very first summer that we were able to spend in its entirety at our Cabin in the Sky. We arrived on the last day of June, and returned the day before Labour Day, just ahead of the start of classes for Alexandre and me, and work for Loula.

In the weeks leading up to the start of that glorious summer, I obsessed over my imaging plans. I thought there was a good chance that I could go "deep" on as many as four objects - and after 18 months of experience using my observatory, and with my skills in image processing having improved as a result, I defined "deep" as a minimum of 10-12 hours!

I scoured the web for targets, starting with APOD of course, and the websites of my favourite imagers (Crawford, Fera, Fleming, Gabany, Gendler, Leshin, Hallas, Pugh, ...). The Bubble "popped up" in my search almost immediately, a singular target owing to the powerful illusion of depth. So this became my first target, and I got started on it right away, on just our second night at the Cabin, July 1 - Canada Day!

I hadn't planned on shooting in H-alpha, until I discovered how little of the nebula was present in the broadband red, when I did some quick processing of the LRGB frames from the first few nights of imaging. Unhappily, the weather took a nose dive in the 2nd and 3rd weeks of July, so it wasn't until near the end of the month that I was able to take some Ha frames. By then, I had become fixated on the Ghost Nebula, and for the first time since I commissioned my observatory, I put an unfinished target on hold to purse another (and then another!). I didn't get back to the Bubble until the last two nights of our summer at the Cabin in the Sky, taking quite a chance on coming up short, but happily the weather gods kindly gave me those two nights to complete the project ;).

It took until the end the end of December before I had enough time to fully process the image. With New Year's Eve at hand, I thought it might be fun to compose the frame so that the bubble could instead be imagined as a balloon, having just escaped the grasp of a reveller, and now seen drifting up and away into the clouds ;).