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M101 (The Pinwheel Galaxy)

M101 - The Pinwheel Galaxy in Ursa Major M101 - The Pinwheel Galaxy in Ursa Major ©2015 Frederick Steiling
Target Information
Main Target Designations M101 / NGC5457
Companion Objects NGC5477
RA Center 14h 02m 38.515s
DEC Center +54° 25' 33.20"
Rotation -0.141°
Additional Images
Published image Full resolution
Annotated image Pop up preview
Full resolution
Exposures
One-shot color 28x480" (ISO1600)
Total Integration 3hrs 44min
Date(s) of acquisition 15Mar2015
Location Whiteside, MO
Equipment
Imager Olympus E-P5
Telescope/Lens Orion 8" f/3.9 Astrograph
Mount Celestron CGEM
Guiding Apparatus Orion ST80 (piggyback)
Guiding Camera Orion SSAG
Accessories
Coma Corrector Baader MPCC Mark III
Collimator Orion LaserMate
Focusing Bahtinov mask
Software
Acquisition Manual (remote shutter)
Guiding PHD2
Processing PixInsight 1.8

Next time you're outside on a clear night during early spring, take a look at Ursa Major (the big dipper).  On the handle, draw an equilateral (equal sides) triangle on the scoop-side using the last two stars of the "handle" (Alkaid and Mizar) as the bottom.  At the top point of your triangle sits this magnificent galaxy, the Pinwheel.  Another face-on spiral galaxy, this one presents itself with huge, magnificent arms that seem to go on forever.  Containing a whopping 1 trillion stars and spanning approximately 170 million light years end-to-end, the Pinwheel Galaxy compares well in size to our very own Milky Way.  Combine its size with its relatively close distance to us (21 million light years) and we have one of the brightest and largest spiral galaxies in our sky -- the 4th largest, in fact, beat in angular size (in any direction) only by M31 (Andromeda), M33 (Triangulum), and NGC55 (spiral in Sculptor).

In this shot, I finally stretched the piggybacked guiding setup to 8 minute exposures, and it gave me a huge return on investment with nice outer arm detail.  A good amount of patience with the drift align tool in PHD2 was most responsible for this transition by guaranteeing excellent polar alignment, though tightening a few screws down to help limit flexure between the guide scope and the main tube certainly helped as well.  All in all, the gear is really starting to show what it's capable of, and leaves me very excited to move onto my next target!

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