IC 342 - The Hidden Galaxy in Camelopardalis
IC 342 - The Hidden Galaxy in Camelopardalis
IC 342 - The Hidden Galaxy in Camelopardalis
IC 342 is an interesting spiral galaxy that is also known as Caldwell 5. The galaxy is located very close to our galaxy's galactic plane. This means that we are looking through much of our own galaxy to see this much more distant galaxy. Because of this, IC 342 is partially obscured by our galaxy's interstellar material. For this reason, it is often called the "Hidden Galaxy".

As far as galaxies are concerned, IC 342 is fairly close to us - it is one of the dominant members of a galactic cluster that is very close to our Local Group. Because of its relative proximity, IC 342 would be one of the brightest galaxies in the sky if it were located farther away from the Milky Way's galactic plane.

IC 342 has a large apparent size in the sky - it is about 20 minute in diameter (about 2/3 this size of a full moon). Due to its large size and obscuration from the Milky Way, IC 342 has a VERY low surface brightness. This makes it a quite challenging object to photograph.

In this image, North is Up. This image is cropped to 84% 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
Guiding 80mm f/11 guidescope with PHD Guiding
Camera Canon 20Da
Exposure 144 subexposures of 180 seconds at ISO 1600 - over 7 hours of total exposure
Calibration 30 darks, 30 flats, 30 bias
Date November 21 and 25, 2011
Temperature 41F on 11/21, 49F on 11/25
SQM Reading
Seeing 3 of 5 on both nights
Location Pine Mountain Club, California
Software Used Images Plus 4.0 for camera control, calibration, and stacking. Images Plus 5.0 for digital development, multiresolution sharpening, star shrinking, smoothing and noise reduction. Photoshop CS5 used for levels and curves, selective color, high pass filter, star shrinking, lab color, saturation adjustments, screen mask invert, lens correction, and smart sharpen. Gradient Xterminator for gradient removal. Carboni Tools for additional saturation adjustments, noise reduction, and smoothing.
Notes This is a reprocess of an earlier version of this image using my DSLR-LLRGB workflow which allowed me to stretch the thin data more aggressively while keeping the chromatic noise to a relative minimum.

Most photos of this object tend to show it as fairly pink in color. This is primarily due to interstellar material absorbing light from the distant galaxy. In this image, I've intentionally made the galaxy's color more blue. This represents what the galaxy would probably look like if it was located in the sky farther away from the Milky Way's galactic plane (plus I think it looks better!).

The earlier version of this image won 1st place in Astrophotogallery.org's December 2011 "Hard-Galaxy" category as well as Digital Astro's Challenge Photo - Galaxy category for December 2011

This image was published by Astronomy Magazine as its Picture of the Day for January 3, 2013 (my 4th!).