Sep 24th, 2016 - The Triangulum Galaxy (M33) is a spiral galaxy approximately 3 million light-years from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598. The Triangulum Galaxy is the third-largest member of the Local Group of galaxies after the Milky Way and the Andromeda Galaxy.

Now I decided to capture multiple filters to create a HaLRGB image which I will explain later on how this is done, during capturing the Ha data I did notice a lot of nebulas within the galaxy’s arms and I also captured many exposures to bring in all the beautiful details of this galaxy.

These are the data that I captured all with EdgeHD 9.25” hyperstar and ZWO ASI1600MM at gain 300

• Red filter, 20subs at 60sec

• Green filter, 20subs at 60sec

• Blue filter, 20subs at 60sec

• Lum filter, 15subs at 30sec, 56subs at 60sec, 20subs at 120sec

• Ha filter, 20subs at 120sec, 36subs at 180sec

The reason I captured a longer exposure using the Ha filter is because there were lots of amazing shapes and nebulas that I really wanted to bring in the final image.

The processing bit took me a while to digest and understand and I really wanted to be perfect so here is how I’ve done it, I mainly done all of it in PixInsight.

1) Calibrated each of the Ha, Lum, Red, Green, Blue filter with its (Dark, Bias and Flat) frame

2) Stacked each individual filter/exposure together.

3) HDR combines all three exposures of Lum and the two different exposures of Ha so I ended up with two master frames of Lum and Ha data.

4) LinearFit both (Ha, Lum) and (Ha, Red) to match their background and then opened PixelMath and run MAX(Ha, Lum) and (Ha, Red), the final frames were simply HaL, HaR, G, B with Ha data added to both Lum and Red channel.

5) Combined all the color channels to create a master (HaRGB) and boosted up the saturation.

6) Run (Deconvolution, Background noise reduction, Star Reduction) to the HaL frame to improve the details and reduce the noise.

7) Combines the HaL to the HaRGB to create the final HaLRGB which I enhanced it a little bit in Photoshop to improve the sharpness and color pattern.

I have to say, the final image looks really WOW especially with all the Ha data, if you zoom in you will see shapes that simply look amazing, in our Milkyway galaxy we have many nebulas that looks great but compared with M33, they really have a lot more nebulas and just imagine if there is a planet there that contain people with Astrophotography hobby I bet they are lucky to have so many DSO within their galaxy, I really hope you like it.