M33 – The Triangulum Galaxy

I was finally able to go out to Anza for the AT8RC’s first light on 12/26. It was a pretty good night with no wind and a very clear sky. I started out with M33.

I had tried M33 with the AT65EDQ before and while processing it I thought I was missing aperture to capture the details. Because of that I kind of expected M33 to be a easy target for the 8″ RC. I have to admit that I was wrong… M33 really is faint!

I started with short exposures as I wanted to make sure tracking and guiding were working ok. I did experience some … things with the G11. When I moved to 5-minute exposure, guiding would go crazy just as if the mount wasn’t applying the correction sent by PhD / autoguider port. It actually wouldn’t restart until I stop guiding AND slew to another target and come back to M33. I did this maybe 3 or 4 times before it decided to work flawlessly for the rest of the night. Maybe it’s firmware related and as I didn’t have time to test out PAC and as guiding was working great with the AT65EDQ I didn’t want to mess with it. But I guess it is now time to update the firmware. That being said, when the guiding issue was gone I was able to push to 10-minute exposure without any problem.

I just hope nothing is wrong with the mount mechanically – when I first started slewing, I did hear some weird noise coming out of the RA motor/worm area (can’t tell precisely where it was coming from but it was definitely in RA). Being in the LA area, I am not too far from Losmandy and maybe this is worth checking with Scott – and maybe consider doing the OPWB/Maxxon motors upgrade at the same time.

Moving on… I guided using the AT65EDQ on top of the 8″ RC. No picture of the set up for now, I got up late that morning and completely forgot to take pictures of the setup.

I had some little troubles with my model too. First, having only a 25 mm cross-hair eyepiece creating a model was pretty difficult, I just couldn’t find my first star (with one star aligned, the next ones are usually almost spot on and only need minor adjustments). I ended up using the AT65EDQ with this eyepiece to align and then adjust it with the 8″. My RDF is pretty useless at the moment as it’s absolutely not aligned with the two scopes. For next time, I bought a diagonal and a 40 mm eyepiece which should make things slightly better.

Dan gave me great advises (as usual!) and decided to follow his advise by checking out PixInsight. This is a real great piece of software! Thanks Dan for all great advises and PixInsight tips! I used DSS to stack all my subs. I actually had three sets of exposures which I like to use: 120 s, 300 s and 600 s. I first stacked them individually as I usually blend them using HDR and masks and I realized that I really didn’t any saturated area even in my longest subs. So I ended re-stacking everything using groups and the “Entropy Weighted Average” in DSS. I thought this should give me a slightly better N/S ratio – but that’s just a guess.

I processed the image with PixInsight 1.7 and only used photoshop to put my name at the bottom :)

Here is the result and as usual image details are below:

  • Date: December 26th 2011
  • Camera: Canon 500D Baader Modified and CP30T-EOS Cooled (Sensor maintained at 10 C – Exif temperature: 10 C)
  • ISO: 1600
  • Exposures: ~ 2.5 hours total of 120 s, 300 s and 600 s subs
  • Mount: Losmandy G11 Gemini 2
  • Imaging Telescope: AT8RC w/ AT2FF
  • Guiding Telescope: AT65EDQ w/ SSAG
  • Calibration: Darks, Flats
  • Stacking: DSS (Entropy Weighted Average)
  • Final blending/processing: PixInsight 1.7 and Adobe Photoshop CS5
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One Response to M33 – The Triangulum Galaxy

  1. Bruce says:

    I enjoyed visiting your website. As a beginning imager I am always curious to see how others are doing it. My object of interest is M33 and I was becoming somewhat disappointed at the apparent lack of detail I was getting. BUT, as I researched further, I realized that the Triangulum Galaxy can be difficult because the details are so faint. I have about 2 hours of time in now and plan to keep gathering photons!

    Good job on the website!

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