NGC 3628 - the 3rd Galaxy in the Leo Triplet (reprocessed)
NGC 3628 - the 3rd Galaxy in the Leo Triplet (reprocessed)
NGC 3628 - the 3rd Galaxy in the Leo Triplet (reprocessed)
NGC 3628 is an edge on spiral galaxy in Leo. Often called "Sarah's Galaxy" and the "Hamburger Galaxy", it is the third galaxy of the Leo Triplet. Its companions are M65 and M66 and the three bright galaxies are within about 2/3 of a degree of each other (the full moon is about 1/2 degree). NGC 3628 displays a beautiful dust lane bisecting it. Very long exposures can reveal the "tidal tail" - a string of stars and gas that extends to the west by almost a degree (about 4 times the diameter of the galaxy itself!). The tidal tail is caused by the gravitational interaction with M65 and M66.

In this image, North is Up. This image is cropped to 50% of the original full frame.

Exposure Details
Lens Celestron C-8 SCT with Celestron focal reducer
Focal Length 1260mm
Focal Ratio f/6.3
Mount Schaefer GEM - 7 1/2 inch Byers gear
Guiding 80mm f/11 guidescope with PHD Guiding
Camera Canon 450D - Gary Honis modified
Exposure 241 subexposures of 180 seconds each at ISO 1600 - 12 hours total
Calibration 30 darks, 30 flats, 30 bias
Date January 25, 27, and 28, 2012
Temperature 48F on 1/25, 39F on 1/27, 42F on 1/28
SQM Reading 19.2 on 1/25, 1/27, and 1/28
Seeing 3 of 5 on 1/25, 2 of 5 on 1/27, 3 of 5 on 1/28
Location Pine Mountain Club, California
Software Used Images Plus 4.0 for camera control, calibration, stacking, digital development, multiresolution sharpening, smoothing and noise reduction. Photoshop CS5 used for levels and curves, color correction, selective color, high pass filter, lab color, match color, saturation adjustments, and screen mask invert. Gradient Xterminator for gradient removal. Carboni Tools for additional saturation adjustments, noise reduction, and smoothing. HLVG for additional color correction.
Notes I photographed this galaxy for over 16 hours in hopes of capturing the elusive tidal tail. As it happens, 16 hours still wasn't quite enough to image anything more than a hint of the tidal tail. As it happens, I unfortunately photographed this object on 3 of the brightest nights I've ever had in PMC. I haven't given up on the tail, as I plan to add more time to this object next year. I'm determined to capture the tidal tail.

Nonetheless, I figured I had enough data to make at least a pretty decent image of the galaxy. It isn't optimal, as I had the galaxy in the corner of the field of view in order to capture the tail going through the center of the image. As such, the galaxy wasn't positioned in the optimal part of the telescope's optical path. That having been said, I think the image still came out rather well (although its not as precisely sharp as it could have been).

An earlier version of this image won 1st place in Cloudy Night's February 2012 DSLR Imaging/Sketch