M33 - The Triangulum Galaxy

Click on image to enlarge

Object: Messier 33 (NGC 598/604)

Type: Spiral galaxy 

Distance: 3,000,000 light years 

Constellation: Triangulum

Date: 25 November & 07 December 2017
Equipment: SXV-H9, Vixen 114mm f5.3 ED refractor, guiding with Lodestar X2/PHD

Subframes: 50 x 300s luminance (via an Astronomix CLS filter), 20 x 80s 2x2 binned each for Ha, RGB

Images acquired, pre-processed and stacked in Astroart.  Digital development and high/low pass filters applied, colour composited all in Astroart.  Final cosmetic processing (cropping, mild edge preserving smooth for noise) in PaintShop Pro.

The bright red patch at upper right centre is NGC 604, the brightest of the numerous H-alpha emission regions in this galaxy.  This image could have probably done with longer luminance subs as the outer arms are not as well defined as I would have liked.  I had previously imaged M33 in "white light" and actually got better luminance data with shorter exposures, suggesting that the CLS filter wasn't actually helping

More information about this object can be found here.

A 40mm eyepiece on the ED114 shows M33 up as a definite central glow fading to a less obvious oval, featureless glow about half the size of the full moon. This seems to equate to the brighter inner arms as shown in the image above. Visually, I can't see any hint of spiral structure.