M101 – Face-on Spiral Galaxy in Ursa Major

Telescope: ES Comet Hunter MN6 at f/4.8, Orion Atlas EQ-G

Camera: Baader modified Nikon 610; Gain: 200

Filter: High Point 2” IR Blocking Filter

Guide scope: Williams Optics 50mm, ASI290MM mini, PHD

Exposure: 42x60sec (3/19) + 15x120s (3/20), saved as RAW

Darks: Internal (Long Exposure Noise Reduction On)

Flats: 32×1/4sec, tee shirt flats taken at dusk

Average Light Pollution: Red zone, Bortle 8, poor transparency

Lensed Sky Quality Meter: 18.2 mag/arc-sec^2

Stacking: Mean with a 2-sigma clip.

White Balance: Nebulosity Automatic

Software: Backyard Nikon, Nebulosity, Deep Sky Stacker, Photoshop

M101 is a wonderful face-on spiral just north of the handle of the Big Dipper. It is also something of a monster, nearly twice the size of the Milky Way, making it one of the largest spirals known. This field also shows several other galaxies, some of which are satellites of M101. At the bottom of the field in NGC 5474, a dwarf spiral. At the top of the field is a tiny edge-on spiral, NGC 5422.

M101 is a circumpolar object that never sets from mid-northern latitudes. It rises with the handle of the Big Dipper and is visible in the northeast in the early evening and is high overhead at midnight.