NGC 650 (aka M76)


Object: NGC 650, planetary nebula in Perseus, 10.1m, 3.1'x3.1'.


Subimages:1x1200s and 3x600s (0.8 hrs) combined using SD Mask.
Calibration: Bias and darks only. I wish I had done flats since a nasty dust donut was visible at the bottom of the frames.
Scope: C11XLT with RLS65 reducer, EFL=1981mm (f/7 effective)
Mount: Losmandy G11 with Gemini L4
Camera: ST7EI (0.94"/pixel) set to -20C oriented at -87d19' (E up, N right)
Guiding: SX716 camera on a Taurus Tracker III OAG. Exposure time 2 sec and 1 sec.
Acquisition and Processing: MaxIm DL/CCD v4.5
Imaged on: Oct. 8, 2006

The first 20 min frame had some bad DEC trailing and some bloom spikes, so I shortened the following frames to 10 min. Frame 2 had very good seeing and tracking (FWHM=2.3"), however frames 3 and 4 suffered from some minor RA elongation. I had ambitions of much longer total integration, however prolonged lousy weather cut things short. In order to reveal the outer lobes I will need more signal, next time.

Processing:
Background flattened manually with a complex polynomial bgd 20+ points.
Cropped keeping 3:2 aspect ratio and removing ugly dust donut.
L-R deconvolution: Auto bgd and noise settings, PSF gaussian radius=1.46, 60 iterations
DDP (gamma stretch): bgd=8520, mid=9300 and no filter
Remove blooms on 2 brightest stars.
Cloned 4 brightest stars from non-LR DDP version

Non L-R deconvolution version

Same processing except no cloning required and the background was filtered with a low-pass FFT.