7 - 15 min. exposures with the SBIG ST-8300M (monochrome) CCD camera at -10C. Baader 2" UV/IR filter. Telescope configuration: TEC-140 (980mm, f/7) with the AP 27TVPH .75x focal reducer, yielding 806mm, f/5.76 and an image scale of 1.38 arc-seconds/pixel. Mount: Losmandy G11 w/Gemini. Focused using a Bahtinov focus mask. Post processing: bad pixel removal in Nebulosity2 using 20 dark frames (threshold 5240); calibrated using 20 bias frames, aligned, Min/Mix excl avg combined and DDP applied in ImagesPlus 3.82 (Auto Image Set Processing). Curves in Nebulosity2. Image cropped from original of 3352 x 2532 to 1024 x 768.

20100418_NGC4535_CombExcAvg-ddpcrvadjcrp.jpg