M74


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M74: This nice, symmetric, face-on, "Grand Design" spiral galaxy is one of the dimmest galaxies in the Messier catalog. It is found in the constellation Pisces.

Messier: 74
NGC: 628
Right Ascension: 1h 36m
Declination: 15° 47'
Apparent Magnitude: 10

Date: September 2010
Equipment:
Telescope: Meade 16" Schmidt Cassegrain with f6.3 reducer (used at ~ f6.1)
Camera: SBIG ST-10XE
Guiding: AO-8

Exposure: 9x10 minutes
Processing Notes: Data acquisition with CCDSoft. Reduced and aligned in CCDStack. Subs combined in Sigma Beta. Arcsine stretch import of L into Photoshop. Adjusted curves and levels. Increased contrast via a highpass filter overlay layer. Slight blur on the dim areas and sharpening on non-star bright areas. Minimize filter on the stars.
Scale: 0.52"/pixel on highest resolution

Links to images of this object on other sites:
http://apod.nasa.gov/apod/ap030524.html
http://www.noao.edu/outreach/aop/observers/m74.html

Additional Comments: This is the first image after "loosening" the mirror. This allows the mirror to "flop" slightly, and would be bad for guiding using PHD, but the through-the-lens guiding using the AO-8 compensates for any image drift. As a result, the stars near the edges look rounder to me. The highpass filter increases the apparent star size on the brighter stars, so additional processing will likely be attempted once the RGB data is available. Also, there was an unexpected horizontal gradient from some new flats, so those will be re-taken, and the image re-processed.

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