IC5146 - The Cocoon Nebula
Description: IC5146, the Cocoon Nebula, is located in the constellation of Cygnus. This image was taken on August 2, 2008 at the Table Mountain Star Party between Ellensburg and Wenatchee in central Washington.
My first attempt at this object was on July 28. The conditions were good. I framed it and started guiding. The guiding was spot on, but the images coming out of the main camera were a complete mess with all of the stars leaving long trails. After some quick troubleshooting, I found that the guide scope had become dislodged from the rearmost 3 point ring and was hanging free on one ring. It turns out that earlier in the day, I was working on some cabling underneath the scope in my observatory tent. When I stood up, I hit my head hard on the scope. I was seeing plenty of stars even though it was daytime. I guess that when I hit it, I dislodged the guide scope. After tightening down the guide scope, I decided to check everything out. So I tightened all the fittings, tweaked collimation, and fixed polar alignment which was off by almost a degree (I hit the thing really hard with my head.) By the time all of this was done, it was too late to get a full set of exposures.
July 29 was clouded out, so my second attempt was on July 30. I got everything set up and framed. Guiding was on. I got one really nice luminance exposure and then the clouds rolled in. I waited about an hour until midnight or so and it was still overcast so I gave up for the night. I did manage to find out later that it cleared off nicely at 1:00am. Oh well...
July 31 and August 1 were marginal. I did some visual stuff through the holes in the clouds, but no imaging.
August 2 was the last night of the star party and by this time, I was determined that I wanted this shot. As it happened, the conditions were pretty good. The wind was light and the sky was clear. It was very damp out, but I was able to keep the scopes clear and get this one. After that work, I didn't even bother to look at the data until I had been home for a few days. Happily, the data was good and I am pleased with this shot.
Equipment: The image was taken with an 8" Meade LX200ACF telescope on a Celestron CGE mount. The camera was an SBIG ST10XME with an Astro-Physics .67 Telecompressor and Astrodon filters. The guide scope and camera were an AstroTech AT66ED refractor with an SBIG remote guide head attached to the ST10. Focusing was done with an Optec TCF-S focuser with temperature compensation turned off.
Exposures: 22x300 seconds luminance binned 1x1; 8x300 seconds each red, green and blue exposures binned 2x2.
Processing: Bias, dark & flat calibration, image registration & color registration were done in Maxim/DL. Curves, levels, LRGB combination, zone sharpening & noise reduction were done in Photoshop CS2. Gradient processing was done with GradientXTerminator.
Click on image for full resolution.