M61 - The Swelling Spiral Galaxy in Virgo
M61 - The Swelling Spiral Galaxy in Virgo
M61 - The Swelling Spiral Galaxy in Virgo
M61 is a grand design barred spiral galaxy about 50,000 light years from us. Grand design spiral galaxies have 2 or more distinct spiral arms, and barred spiral galaxies have a longitudinal bar across the nucleus of the galaxy. While M61 is one of the largest galaxies in the Virgo Cluster, its apparent diameter in the sky if fairly small - about 6 arc minutes (or 1/5 the diameter of the full moon).

Also featured in this image are 2 companion galaxies to M61. NGC 4301 is a barred spiral galaxy to the upper left of M61. NGC 4292 is yet another barred spiral galaxy to the upper right of M61 and has a satellite galaxy just above it. The galaxy at the very top of the image is UGC 7411, and there are a number of faint galaxies scattered throughout the image.

In this image, North is Up. This image is cropped to 73% of the original full frame.

Exposure Details
Lens Celestron C-8 SCT with Lumicon telecompressor
Focal Length 1100mm
Focal Ratio f/5.5
Mount Schaefer GEM - 7 1/2
Guiding Unguided
Camera Canon 20Da
Exposure 257 subexposures of 45 seconds at ISO 1600 - a little over 3 hours of total exposure
Calibration 30 darks, 30 flats, 30 bias
Date May 25 and 26, 2011
Temperature 44F on 5/25, 48F on 5/26
SQM Reading
Seeing 2 of 5 on both nights
Location Pine Mountain Club, California
Software Used Images Plus 4.0 for camera control, calibration, stacking and digital development and multiresolution smoothing. Photoshop CS5 used for flat fielding, levels and curves, color balance, high pass filter, star shrinking, saturation adjustments, and noise reduction. Carboni Tools for additional saturation adjustments and noise reduction. HLVG used for additional color correction.
Notes I took this astrophoto before I had upgraded my mount for autoguiding. As such, the subexposures are only 45 seconds. While the image is far from optimal, I was glad that I was able to pull out a surprising amount of faint detail in the galaxy and surrounding field.