M31 Andromeda Galaxy

[Chefgage]

Here is my effort of M31.  Taken from a bortle 3 to 4 sky whilst on holiday in Devon.  Unfortunately I had only one clear night during the week and then only got an hour before the moon came into play.

Canon 200D, sky watcher 72ED, star adventurer pro tracking mount.

131 lights taken at 30 second exposure @ iso 3200, 40 darks.

Stacked in DSS and processed in GIMP.  Looks like I over stretched the image so I need to have another go at processing this image, ah well.

 

[MarkAR]

A good start, worth trying longer exposures at lower ISO.

[Chefgage]

17 minutes ago, MarkAR said:

A good start, worth trying longer exposures at lower ISO.

Although I believe my polar align was very good I was getting star trails at 60 second exposures.  So I went with 30 second ones.  I might try upping it to 45 second exposures and the next step I suppose would be guiding on the star adventurer.

[alan potts]

Indeed a good start, M31 is a very difficult target to process, recent I read account from really top imagers where they still are not happy with the way the core came out, I never am either. Try a look at Astro backyard, he has a few very useful tips on this target and are not over difficult to follow.

Alan

[TerryMcK]

There is still a lot of data in there you've just got to tease it out. An autostretch of the jpg in PixInsight revealed lots of stuff. As Alan says try Trevor Jones's Astrobackyard tutorials and you will get lots more out of the picture.

[Chefgage]

22 minutes ago, TerryMcK said:

There is still a lot of data in there you've just got to tease it out. An autostretch of the jpg in PixInsight revealed lots of stuff. As Alan says try Trevor Jones's Astrobackyard tutorials and you will get lots more out of the picture.

Thanks, i will take a look. I was planning on spending more time on it. I only spent 5 minutes on the levels and curves in gimp.

After about the 100th image the moon started to come up so each sub after the 100th starts to get lighter and lighter. So i will probably cut back the amount of subs. Or can DSS determine the ones to bin???

[ollypenrice]

I would concentrate on two things with the original data. 1) Get the colour channels balanced and 2) Stretch without clipping the black point. I'm sure your data has more to give.

Olly

[Chefgage]

2 minutes ago, ollypenrice said:

I would concentrate on two things with the original data. 1) Get the colour channels balanced and 2) Stretch without clipping the black point. I'm sure your data has more to give.

Olly

Thanks for that. Going to sit down and spend some time on this. Need to get the best out of it seeing as it was the only set of data I managed in my holiday.

[ollypenrice]

6 minutes ago, Chefgage said:

Thanks for that. Going to sit down and spend some time on this. Need to get the best out of it seeing as it was the only set of data I managed in my holiday.

Processing is a huge part of imaging...

Olly

[Chefgage]

On 14/08/2020 at 20:20, ollypenrice said:

I would concentrate on two things with the original data. 1) Get the colour channels balanced and 2) Stretch without clipping the black point. I'm sure your data has more to give.

Olly

When you say get the colour channels balanced, how would I go about doing that if you don't mind me asking.

[szymon]

I am certain that you have a lot more in that data than the picture you produced shows.  You need to learn to tease it out.  The best advice here is for you to spend some time learning to process your data.  This is where a lot of the skill of astrophotography actually lies.  Anyone can follow instructions to polar align a mount, point a scope at the sky and take images.  But in this day and age of digital imaging, it's what you do with the data you get that matters!

I'm attaching a photo to encourage you.  The attached image is not great in any way.  There is very little actual exposure time, less than half of what you have.  Worse, this was taken from my back garden, in Light Polluted London -- Bortle 8 on a good day, but there was also a full moon (this was on Saturday).  There were clouds all around, I only had the scope out to work on getting my spacing and tilt correct and then when I gave up on that (you can still see how off it is from the photo) I decided to use M31 as a test image.  I pointed the scope and managed to get 31 minutes of exposure, 7 x 60s L and 4 * 120s each of R, G, B (I am using a ZWO ASI1600-MM Pro with Baader LRGB filters), through thin high clouds before the thicker clouds really came in and made it impossible.  This is way way less data than your image, and I guarantee that the quality of the data is lower, but processing it correctly managed to pull out the following:

Once stacked, my processing steps here in PixInsight were (from memory):

• On L: DBE, deconvolution, tgvdenoise, mmt for NR, arcsin stretch
• On each of R, G, B: Multiple levels of DBE (more interested in getting rid of the gradients than preserving detail), arcsin stretch
• LRGBCombination, histogram stretch, Photometric Colour Calibration, curves for saturation hue and contrast, local histogram equalisation, mmt, mlt

That's what worked on my data.  It will be different for your OSC data.  You might use different tools, you might stack in a different program, etc -- but whatever you use, I encourage you to keep going, because the data is there, you just need to pull it out!  If there is this much in half an hour in bortle 8, I am absolutely certain that you can get more from over an hour of the same target in bortle 3/4 🙂

-simon

[szymon]

I forgot to say, since you're using GIMP here is a useful tutorial about processing astro images in GIMP.  Ruzeen explains things nicely, well worth watching.

 

 

[ollypenrice]

2 hours ago, Chefgage said:

When you say get the colour channels balanced, how would I go about doing that if you don't mind me asking.

The best way I know involves using Pixinsight's Dynamic Background Extraction but I think other astro-specific programs like APP can also do a good job. If using GIMP (which I don't know but is probably like Photoshop) then you can begin by looking at the histograms of each colour channel. The rule of thumb is to get the top left of the histogram peak aligned in each channel. You can move them by bringing in the black point to move the peak to the left. There is no reasonable way of moving it to the right. Then you can measure the colour balance in the background sky. In Ps you use the colour sampler for this, set to 3x3 pixel average, probably. I'd be surprised if GIMP didn't have an equivalent. I aim for parity in each channel for the background. Some like blue to be higher but I certainly don't.

Olly

[x6gas]

Steve Richards (@steppenwolf on here and author of two books that give great introductions into astrophotography) gave a brilliant StarGazine talk last night on basic processing that I think you'd find very interesting and useful - the YouTube video of the talk is already online.

[tomato]

Take a look at the StarGazine EP18 YouTube video on this forum (assuming it has been uploaded from last night), Steve Richards takes you through how to balance the colour channels in Photoshop, the process in GIMP will be very similar.
 

I’ll echo the other posters, there is more to be had from your data.

[tomato]

@x6gas beat me to it!

[Chefgage]

5 hours ago, szymon said:

I forgot to say, since you're using GIMP here is a useful tutorial about processing astro images in GIMP.  Ruzeen explains things nicely, well worth watching.

 

 

Thanks, I will take a look.

[Chefgage]

2 hours ago, x6gas said:

Steve Richards (@steppenwolf on here and author of two books that give great introductions into astrophotography) gave a brilliant StarGazine talk last night on basic processing that I think you'd find very interesting and useful - the YouTube video of the talk is already online.

Thanks,  I will give it a watch.

[Chefgage]

2 hours ago, ollypenrice said:

The best way I know involves using Pixinsight's Dynamic Background Extraction but I think other astro-specific programs like APP can also do a good job. If using GIMP (which I don't know but is probably like Photoshop) then you can begin by looking at the histograms of each colour channel. The rule of thumb is to get the top left of the histogram peak aligned in each channel. You can move them by bringing in the black point to move the peak to the left. There is no reasonable way of moving it to the right. Then you can measure the colour balance in the background sky. In Ps you use the colour sampler for this, set to 3x3 pixel average, probably. I'd be surprised if GIMP didn't have an equivalent. I aim for parity in each channel for the background. Some like blue to be higher but I certainly don't.

Olly

Thanks, I will give this a go.  

[Chefgage]

Thank you everyone for your suggestions. I am very happy with what I achieved with the data I collected and processed. My processing skills are improving, so I will keep at it.

Edited September 7, 2020 by Chefgage

[Pryce]

1 hour ago, Chefgage said:

Thank you everyone for your suggestions. I am very happy with what I achieved with the data I collected and processed. My processing skills are improving, so I will keep at it.

Did you ever give it another go at processing? If so, show us the result! 😁

[Chefgage]

9 hours ago, Pryce said:

Did you ever give it another go at processing? If so, show us the result! 😁

No not yet. But I will do soon and share the result.