M81 and M82 - Astrophotogallery

M81 & M82
2010-03-17, 10:39PM EDT to
2010-03-18, 1:08AM EDT

Middlebury, VT
Constellation - Ursa Major

Exp 11x720sec (12min) subs (2hr 12min total)
ISO 1600

Focus was soft. By the time I managed to find a star the autoguider could lock onto I didn't want to go back to re-check the focus. The seeing was poor and the tracking was problamatic, had to use 5sec integrations and that's a little too long for my setup. All the subs had a little trailing and could not use 4 of them. 12 minutes may be pushing it with my setup as well, though the previous night I got some sharp images of what I hoped were "The Antannae" with 12 minute subs using 1sec integration time on the autoguider. Turned out to be 2 rather non-descript 14th mag galaxies, NGC4285 & 44279 (Ididn't want to disturb my wife to find out what they were, my computer is in the bedroom).

North - left

10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics)
Field of view: 0.90 x 0.60 deg.
Large Wooden Split Ring Equatorial Mount

Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin)
with Orion Broadband Light Pollution Filter

Temperature - 38 to 34 degree F
Transparency 20.83 to 20.93 mag/arc sec (Sky Quality Meter)
20.83 to 21.01 at the zenith
Seeing 4 (1-10)

Autoguider (Meade Pictor 201XT)

Stacking - Registax 5
Noise Reduction - Noise Ninja 2
Other - Picture Window Pro 5

Processing Steps:
Stack of 11, 720sec subs using darks (20) and Flats (30). Small amount of wavelet sharpening in Registax. Regular historgram stretch. Unsharp Mask sharpening. Selective color correction. Historgram stretch (to darken background).

M81 & M82_11x12min_10inf5.6_2010-03-17_wav1_chist_hist_unshp-cc-hist-(medium).jpg