M33 - Triangulum Galaxy

[endless-sky]

I would like to share my third image.

I finally had a "lucky week", since my last session, December 18th. I managed 5 clear nights out of the past 6 (has to be a record, at least for me and my area) and I was able to finish a couple of projects I had started long ago and start a few new ones.

This is M33, also known as the Triangulum Galaxy, taken over 10 nights, under my Bortle 5/6 home sky.

Total integration time: 10h 14m 00s.

Here are the acquisition details:

Mount: Sky-Watcher NEQ6 Pro

Telescope: Tecnosky 80/480 APO FPL53 Triplet OWL Series

Camera: D5300 astromodified

Reducer/flattener: Tecnosky 4 elements, 0.8x

Guide-scope: Artesky UltraGuide 60mm f/4

Guide-camera: ZWO ASI 224MC

2020/11/08: Number of subs/Exposure time: 11@240s. Notes: L-Pro filter, no Moon

2020/11/09: Number of subs/Exposure time: 10@240s. Notes: L-Pro filter, no Moon

2020/11/20: Number of subs/Exposure time: 15@240s + 4@300s. Notes: L-Pro filter, Moon 30% illuminated

2020/11/21: Number of subs/Exposure time: 22@300s. Notes: L-Pro filter, Moon 45% illuminated

2020/11/24: Number of subs/Exposure time: 20@300s. Notes: L-Pro filter, Moon 75% illuminated

2020/12/13: Number of subs/Exposure time: 12@300s. Notes: L-Pro filter, no Moon

2020/12/14: Number of subs/Exposure time: 8@300s. Notes: L-Pro filter, no Moon

2020/12/18: Number of subs/Exposure time: 6@300s. Notes: L-Pro filter, Moon 20% illuminated

2021/01/10: Number of subs/Exposure time: 9@300s. Notes: L-Pro filter, no Moon

2021/01/11: Number of subs/Exposure time: 15@300s. Notes: L-Pro filter, no Moon

Total exposure time: 36840s = 10h 14m 00s.

Pre and post-processing: PixInsight 1.8.8-7.

Image was Drizzle Integrated and then cropped to original sensor size (6016x4016), without resampling. So, it appears as if taken ad double the focal length (768mm instead of 384mm). Image scale 1.04 arc-sec/pixel.

Here's a link to the full resolution image: Triangulum Galaxy (M33)

Thanks for looking!

C&C welcome!

[Padraic M]

Great result! M33 is a tough target, it's so faint.

Edited January 16, 2021 by Padraic M

[endless-sky]

Thank you!

I am mainly interested in nebulae, since right now I have neither the mount nor the scope to capture small galaxies. But M33 is fairly large and I gave it a try anyway. One hour here, one hour there (that's why it took me so long to finish it), while I was waiting for other targets to be high enough in the sky to begin imaging them.

However, I was particularly pleased and had a wonderful feeling when I started seeing H-alpha regions (nebulae) appearing in the galaxy itself, as I was post-processing it. It is amazing that I can capture nebulae that are on a galaxy 2.9 millions light years away from us!

[GiorgioF]

Pleasant and nice result.

Still some egged star (small, top right) but easy to manage.

Did you try to keep the backfocus of the 0,8x ad 61mm from sensor?

[endless-sky]

Thank you, Giorgio!

I thought the backfocus was supposed to be 55mm and I have been struggling to get it right. But then I saw on the website of teleskop-service in Germany that the backfocus for their 4 elements reducer is actually 61mm. Mine looks a lot similar to that one, despite it being a different brand.

You saying that it needs to be 61mm also confirms the theory.

Next Full Moon I will give it a try increasing it to 61mm and see things get better, thanks!

[bish]

Excellent image. Always like to take a look at M33 when I make it to a dark site.

[endless-sky]

Thank you! I must admit that I have never spotted it naked eye, but I took a look at it with my C8, from home. I would definitely like to see it - and Andromeda - just with my eyes!

[bish]

7 minutes ago, endless-sky said:

Thank you! I must admit that I have never spotted it naked eye, but I took a look at it with my C8, from home. I would definitely like to see it - and Andromeda - just with my eyes!

Iv"e not managed it naked eye, even when M31 has been obvious. It's nice to be able to spot it with a small pair of bind, no chance from my back garden.

[GiorgioF]

26 minutes ago, endless-sky said:

Thank you, Giorgio!

I thought the backfocus was supposed to be 55mm and I have been struggling to get it right. But then I saw on the website of teleskop-service in Germany that the backfocus for their 4 elements reducer is actually 61mm. Mine looks a lot similar to that one, despite it being a different brand.

You saying that it needs to be 61mm also confirms the theory.

Next Full Moon I will give it a try increasing it to 61mm and see things get better, thanks!

Everybody got that info but it's a NEW reducer and the BF has been changed. Mine now is 60,5 (fine tune due filters) and all field is flat like you can't believe. More, mind to do not tight touch the fixing screw on rotators due to tilt issue. Tight the right without to much. Feel it.

Clear sky!

[endless-sky]

1 minute ago, GiorgioF said:

Everybody got that info but it's a NEW reducer and the BF has been changed. Mine now is 60,5 (fine tune due filters) and all field is flat like you can't believe. More, mind to do not tight touch the fixing screw on rotators due to tilt issue. Tight the right without to much. Feel it.

Clear sky!

Well, good to know, thank you! I'll definitely try it. Yes, good tip on the rotator screw, I noticed as well that if I do it too tight, it introduces tilting to the image. I have always turned it with my fingers, without forcing it, just enough that it doesn't come loose on its own.