M51: This is a spiral galaxy in Canes Venatici (quite near the end of the handle of the Big Dipper). Estimates of its distance from Earth vary, but the figure given most often is 23 million light years. It is interacting gravitationally with the smaller galaxy on the right of the image, NGC5195, which apparently has greater mass than M51; the dust lane going from M51 to NGC5195 is evidence of that.

Technical Information:

LRGB: 150:50:50:80; L-15 ten minute images; R and G consisted of 5 ten minute images; B consisted of 8 ten minute images. All color images were binned 2x2; luminance images 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: Calibrated (darks, dawn flats and flat darks) and registered with AIP4WIN; L average combined in AIP; RGB median combined in AIP, Richardson-Lucy applied using AIP4WIN. I also took the original combined data and performed DDP in AIP, then layered in the cores of the two galaxies, so that they would not be burned out. Because the color channels also were burning out in the core, I did a DDP on each color channel in AIP; I normally do not do any sharpening in the color channels. Color combined and levels and curves adjusted, and small gaussian blur applied, in Photoshop

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

Date: Luminance images taken during the night of 5/11/02; Color channels taken during the night of 6/9/02.

CCD Temperature: Luminance: -25C; Color: -18C

Copyright 2002 Mark de Regt