Galaxy M101
Galaxy M101 captured with the Vixen VC200L telescope and QHY168C camera.

I was able to borrow and test a Vixen VC200L telescope courtesy of Brian at The VC200L is an 8″ (200mm) clear aperture, 1800mm focal length, catadioptric telescope (CAT). This f/9.0 modified Cassegrain represents the state of the art and it is among the most sophisticated 8″ scopes.


Also used for this image was the QHY168C, OSC astronomy cmos camera. The QHY168C is a cooled USB 3.0 color imaging camera with a large 16-megapixel sensor that offers 14-bit output. The 168C sports the Sony IMX071; an APS-C color sensor with a 4952 x 3288 effective array of 4.8um pixels. 

M101 is a spiral galaxy like our Milky Way, but about 70 percent bigger. It is located about ~25 million light years from Earth.

The giant spiral disk of stars, dust and gas is 170,000 light-years across — nearly twice the diameter of our galaxy, the Milky Way. M101 is estimated to contain at least one trillion stars. The galaxy’s spiral arms are sprinkled with large regions of star-forming nebulas. These nebulas are areas of intense star formation within giant molecular hydrogen clouds. Brilliant, young clusters of hot, blue, newborn stars trace out the spiral arms.

Pierre Méchain, one of Charles Messier’s colleagues, discovered the Pinwheel galaxy in 1781.

M101 is located in the constellation Ursa Major

Image Technical:

16 hours total exposure time
Vixen VC200L 8″ catadioptric telescope @ F9
QHY168C CMOS Camera (, 16mp, 4.8um
Optolong L-pro filter
Skywatcher EQ6 mount / Skyshed Pier (
Pegasus Astro Focus Cube
NINA 1.11 (beta nightly build) for acquisition
Processed in PixInsight
Seeing and transparency: average to good
Location: Kitchener, Ontario, Canada

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