Object: The Pinwheel Galaxy (M101)
Date: 04/14/07
Location: Upham, NM
Telescope: TeleVue 85mm refractor (f/5.6)  on a Meade LXD75 Mount
Guiding: DSI-C and Envisage
Camera: Canon 350XT (modified by Hap Griffin)
Exposure: 20 x 5min, ISO 800, Temp 45 degrees F
Processing: Canon RAW conversion. Dark-frame calibration, registration and stacking (sigma clipped average) in ImagesPlus. Final processing in PS.
Comments: M101 is an extremely large "Grand Design" spiral galaxy in the constellation Ursa Major. Even at a distance of 27 million light years, its 170,000 light year diameter fills a large patch of sky.  This galaxy has a number of unusually large and bright HII star forming regions that are visible in the image as bright patches in the spiral arms.  There is also a notable lack of symmetry in the arms that indicates a recent interaction with another galaxy.  NGC-5474 (right side of image) is a nearby companion galaxy and the most likely candidate. Note the offset galactic core.  For a larger version click here.

© Dave Dockery 2007