Not the most common target for the season but definitely one of my favorite. I wanted to start working on mosaic and based on preliminary work with Stellarium and the Ocular addon, the Veil Complex could be done with only 2 frames with my AT65EDQ combined with the 500D.
I went to the OCA site in Anza on November 27th. It was a good night although a bit windy. I had a few targets on my list and started early with the Veil Complex as I didn’t have much time before it sets. I spent about 2 hours on each frame but had to throw away about 30 minutes worth of data on the second frame because it was just too low on the horizon.
It is worth mentioning that I had been trying to find a new T-adapter that doesn’t have a safety groove and that is short enough because of the lack of much back focus on the AT65EDQ. I have been using the AstroTech T-adapter but I had reasons to believe the safety groove could the cause of some stars elongation. This elongation is independent of exposure length which rules out any guiding or aligning problem. Unfortunately, the Baader self centering T-adapter wouldn’t fit my T-ring and the William Optics was just too long. I tried locking on the end of the AstroTech T-adapter but I was not able to reach focus. I did my best to lock in the safety groove as I had no other choice. It turned out to be all right but I definitely need to address this.
Processing a mosaic is definitely fun and challenging. Having only two frames I gave a shot to DSS in mosaic mode. I would have to work on this a little bit more as I couldn’t find a way to normalize exposure in my post processing. Too bad as it did a perfect job at aligning the frames (as usual!). I ended up stacking both frames independently and did the final processing in Photoshop CS5. Details are below the picture.
- Date: November 27th 2011
- Camera: Canon 500D Baader Modified and CP30T-EOS Cooled (Sensor maintained at 15 C – Exif temperature: 15 C)
- ISO: 1600
- Exposures: ~ 3.5 hours total of 300 s subs (in 2 frames)
- Mount: Losmandy G11 Gemini 2
- Imaging Telescope: AT65EDQ
- Guiding Telescope: Mini Borg 50 w/ SSAG
- Calibration: Darks, Flats
- Stacking: DSS
- Final blending/processing: Adobe Photoshop CS5