M101 - Pinwheel Galaxy

M101 - Pinwheel Galaxy: M101 is a nice face-on spiral galaxy in the constellation Ursa Major.

Messier: 100
NGC: 5457
Right Ascension: 14h 3.2m
Declination: 54° 21'
Apparent Magnitude: 7.7

Date: June 2010
Equipment:
Telescope: Meade 16" Schmidt Cassegrain with f6.3 reducer
Camera: SBIG ST-10XE
Guiding: AO-8

Exposure:
L: 12x10 minutes, binned 1x1
The camera was at -25°C.

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. Slight blur on the dim areas and sharpening on non-star bright areas.
Scale: .575"/pixel

Links to images of this object on other sites:
http://antwrp.gsfc.nasa.gov/apod/ap090414.html
http://www.astropix.com/HTML/C_SPRING/M101_O.HTM
http://www.jthommes.com/Astro/M101C.htm

Additional Comments: This is the "second light" image using the AO-8 "adaptive" optics for guiding. This "new" configuration increased the spacing of the f6.3 focal reducer, moving it to a "non-optimal" f5.5 location. The stars in the corners are definitely affected, and the flat field becomes more critical to the processing. Some dithering (both intentional and inadvertent) artifacts can be seen in the image. The final (color) version using 23 luminance subframes can be seen her: http://www.fortlewis.edu/observatory/image_detail.asp?ID=216

Views: 2225