NGC7640: This is a very dim barred spiral galaxy in Andromeda, shining (as it were) at magnitude 11.5, presenting to us nearly edge on. It is generally estimated to be about 28 million light years from Earth. An extensive search of the Web uncovered no further interesting data on this galaxy.

Technical Information:

LRGB: 190:80:80:130 (L comprised of 5 minute images; RGB comprised of 10 minute images; all unbinned).

Equipment: 10" LX200 at f/4.6, and an SBIG ST-7E camera/CFW-8 color filter wheel

Image Acquisition/Camera Control: CCDSoft V5.

Processing: All images calibrated (darks and dawn flats) and registered in AIP4WIN. Images average combined in CCDSoft. Seven iterations of Richardson-Lucy (high frequency only) applied in AIP4WIN. Color combine, gradient removal, and many careful adjustments of curves and levels performed, and slight gaussian blur applied, in Photoshop 6.0. Special thanks to Ron Wodaski for showing me a useful method for manipulating curves and levels in Photoshop.

Location: My yard in Redmond, Washington, elevation 500'.

Date: Luminance images taken during the night of 9/4/02; RGB images taken during the night of 9/9/02.

CCD Temperature: Luminance images taken at -20C; RGB at -15C

Moon Phase: Luminance taken just before new moon; RGB just after new moon.

Copyright 2002 Mark de Regt