M81 (Bode's Galaxy)
Characteristics:
RA: 9h 55m 34s
Dec: 69 degrees 4' 02"
Position Angle: 268 degrees
Description:
M81 is a grand-design spiral galaxy
that was discovered by Johann Bode in 1774. Due to its
relatively large size and high surface brightness, it is an easy target
for visual observation through small aperture telescopes. M81
forms a galactic pair with M82 (not shown), located only 150,000 light
years apart, and the two galaxies have influenced each other through a
close encounter occurring tens of millions of years ago. Closer
examination of
this image reveals several other small galaxies, as well as a larger
companion galaxy underneath M81, referred to as Holmberg
IX. Also notice the subtle, linear dust lane that courses through
M81, that is thought to be the
result of a past interaction with M82. More information about M81
may be found on Rob Gendler's
site.
Photographic
Details:
Date: January 16, 2010
Scope: Vixen VC200L at f6.4 on the Takahashi NJP
Mount
Autoguider: SBIG ST-402 with
60mm guidescope, focal length 227mm
Camera: SBIG ST8300 at -20C, with
True
Technology Slim filter wheel (1.25" filters, which cause some
vignetting with this chip). This filter wheel will soon be
replaced with the SBIG wheel that accomodates 36mm filters
Filters: Astronomik
clear, R, G, B filters
Exposures: Clear, 160 minutes; Red, 30 minutes; Green, 30 minutes;
Blue 60 minutes, all unbinned.
Total
exposure 4.7 hours
Post-processing:
Calibrated in Maxim, aligned and
stacked using DeepSkyStacker, followed
by DDP
in ImagesPlus (IP). Further processing in Photoshop CS (16
bit format). This image was cropped to remove vignetting caused
by the 1.25" filters. This will be corrected in the future
through the use of larger filters as noted above
Please
note: Graphics on this website may not be reproduced without
author permission.
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