M33 – Spiral Galaxy in Triangulum

Telescope: Meade SN8 at f/4, Orion Atlas EQ-G
Camera: ZWO ASI071MC, Highpoint Scientific UV/IR filter
Sensor Temperature: 0C, Gain: 200, Offset: 50
Guide scope: Williams Optics 50mm, Meade DSI Pro II, PHD
Exposure: 34x120sec saved as FITS
Darks: 32x120sec saved as FITS
Flats: 32x5sec, LED tracing tablet
Average Light Pollution: Red zone, good transparency
Lensed Sky Quality Meter: 18.9 mag/arc-sec^2
Stacking: Mean with a 2-sigma clip.
White Balance: Nebulosity Automatic
Software: Nebulosity, Deep Sky Stacker, Photoshop

This is M33, a giant spiral galaxy in Triangulum (the Triangle). This galaxy hides in plane sight high in the northwest during the late evening this time of year. It is so large (about twice the size of the full moon) that its light is spread out, making it very challenging to see visually except under very dark skies. M33 is the 3rd largest galaxy in the Local Group, behind the Andromeda galaxy and the Milky Way. It is also just a tad further away than Andromeda, about 3 million lights versus 2 million for Andromeda. It is close enough that we can glimpse star clusters and nebula within it, such as the bright star forming region to the upper left.

I kinda snuck this one in after a late night of imaging. After finishing the last target for the night I still had about an hour before the start of nautical dawn. A bit early for M33, but it turned out nice. This is the fourth and last image in a series of images that I am taking to explore the use of a simple UV/IR filter and adjusting the white balance as part of my processing in place of my usual Orion Imaging Skyglow filter. So far, so good!

-John

M33 (7-25-2017)-2j.jpg