[RCC] - Help with Andromeda - Forums

Topic starter

Feb 27, 2023

Hello! I have been taking pictures of DSO's for about a year or two, and have slowly been getting better and better pictures. I recently took some pictures of the Andromeda galaxy, and i really can't pinpoint what to improve, other than just acquiring more data of course.

I am using an astro-modified Canon 600D, and a canon 70-300mm f/5.6 and a Sky-watcher Star adventurer 2i.

Just below is a cropped and edited picture of M31 at 300mm, which is made of 37 x 195s, or about 2 hours.

https://imgur.com/a/bh1THJf

I used SiriL and my workflow was as follows: Color calibration, background extraction and editing curves and levels, color editing in photoshop and then a run through Topaz DeNoise.

Any help would be greatly appreciated. Thanks in advance!

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Carastro

Mar 4, 2023

Hi:

First of all you need to improve your guiding. If not guiding this would make a huge difference to how long you can image for as 195secs is not really long enough to get the best out of a DSLR. However, looks like you are using a Star Adventurer and a camera lens.

Yes guiding with a SA is only in RA I believe so not sure how well guiding will work with that.

I have not imaged much using a camera lens, sorry I am not very much help.

I don't use Siril, so can't advise on that either.

Best results would be obtained from using an Equatrial Mount capable of guiding, and longer exposures.

Carole

Maltasar_

Topic starter

Mar 4, 2023

Carastro:
Hi:

First of all you need to improve your guiding. If not guiding this would make a huge difference to how long you can image for as 195secs is not really long enough to get the best out of a DSLR. However, looks like you are using a Star Adventurer and a camera lens.

Yes guiding with a SA is only in RA I believe so not sure how well guiding will work with that.

I have not imaged much using a camera lens, sorry I am not very much help.

I don't use Siril, so can't advise on that either.

Best results would be obtained from using an Equatrial Mount capable of guiding, and longer exposures.

Carole

Hi Carole, thank you for your comment.

I am a little confused about your comment about exposure time though, as i have seen many pictures with a very similar setup, but also lower exposure time, and less total exposure time, such as this picture:

https://www.astrobin.com/full/fz7iks/0/?q=Andromeda%20canon%2070-300mm

Anyway, thank you again, and i will look into guiding.

Joe Linington

Mar 4, 2023

My thoughts. With a Sky Adventurer, use a laptop and Nina to get as accurate a polar alignment as you can. It can also help centre your target. Then unplug and use your intervalometer. You can guide it in RA but that means extra equipment. Unguided I’m going to advise the opposite, use 30 second to 1 minute exposures. ISO 1600 and shoot as long as you possibly can stand it.

In Siril, I do the background extraction before photometric colour calibration. Also throw in green noise removal anytime you think it looks green tinged. On some projects I use green noise removal between almost every step. Adding Starnet++ to your workflow will allow you to get more out of the galaxy with a starless stretch.

In my gallery is a shot of Andromeda using an A6000 at 344mm f/l. I have a goto and guiding plus my scope is a bit faster than your lens but the biggest difference is 7 hrs of data plus some processing experience. Not that I’m a master by any stretch.

On top of guiding, a goto mount let’s you frame the same target over multiple nights.

Keep at it. You’re off to a great start and the journey is a lot of fun (but expensive.)

Helpful Engaging Supportive

dkamen

Mar 4, 2023

Hi,

Did you use flats and darks?

Maltasar_

Topic starter

Mar 5, 2023

Hi,

Did you use flats and darks?

Hello,

I have just taken some, and will try to see if that makes a difference. I may or may not make an update, as i tend to forget fast haha. Thanks.

Maltasar_

Topic starter

Mar 5, 2023

Joe Linington:
My thoughts. With a Sky Adventurer, use a laptop and Nina to get as accurate a polar alignment as you can. It can also help centre your target. Then unplug and use your intervalometer. You can guide it in RA but that means extra equipment. Unguided I’m going to advise the opposite, use 30 second to 1 minute exposures. ISO 1600 and shoot as long as you possibly can stand it.

In Siril, I do the background extraction before photometric colour calibration. Also throw in green noise removal anytime you think it looks green tinged. On some projects I use green noise removal between almost every step. Adding Starnet++ to your workflow will allow you to get more out of the galaxy with a starless stretch.

In my gallery is a shot of Andromeda using an A6000 at 344mm f/l. I have a goto and guiding plus my scope is a bit faster than your lens but the biggest difference is 7 hrs of data plus some processing experience. Not that I’m a master by any stretch.

On top of guiding, a goto mount let’s you frame the same target over multiple nights.

Keep at it. You’re off to a great start and the journey is a lot of fun (but expensive.)

Hi,

Thank you for the very detailed comment, and some great advice that i will definitely take into use. I have also seen some use Starnet, but it looks kind of advanced, but will of course take a look at it.

Great andromeda image by the way, it looks awesome! And thank you for the kind words, and yeah, very expensive.

Ian McIntyre

Mar 5, 2023

Hi,

Did you use flats and darks?

This was going to be my first question. Very important. I would have to assume you did as Deep Sky Stacker gives you lots of prompts to do so.
My experience with DSLR is similar to your as I was tracking unguided. The lack of guiding and the uncooled sensor mean you will benefit from more subframes with less exposure. The longer your shutter is open, the more heat is generated, which generates noise. My DSLR Andromeda (not that its an award winner) was shot with Canon 77d and 300mm f/4 stepped down to f/6.3 shooting 45 second light frames. You did not mention what ISO you used. I went 800, but 1600 for your camera should be fine. Here is a site that will show you a graph of read noise. https://www.photonstophotos.net/Charts/RN_e.htm. Pick an ISO where the curve starts to flatten. I looked at your model and 800-1600 should suffice.

The other important thing with the darks, flats and bias frames is to make sure you capture them under the same temperature conditions as your light frames.

As far as processing, your chosen software is different than I use (other than Deep Sky Stacker, which I have replaced with the Pixinsight) so not sure I con be much help. Except I will echo a suggestion above to get Starnet++. When I started I used Nico Caver's videos as a guideline. Here is his Siril/GIMP workflow: https://www.youtube.com/watch?v=ambUmZLOeSs&t=0s. It includes a Starnet++ section.

HTH

Helpful

Maltasar_

Topic starter

Mar 5, 2023

Ian McIntyre:
Hi,

Did you use flats and darks?

This was going to be my first question. Very important. I would have to assume you did as Deep Sky Stacker gives you lots of prompts to do so.
My experience with DSLR is similar to your as I was tracking unguided. The lack of guiding and the uncooled sensor mean you will benefit from more subframes with less exposure. The longer your shutter is open, the more heat is generated, which generates noise. My DSLR Andromeda (not that its an award winner) was shot with Canon 77d and 300mm f/4 stepped down to f/6.3 shooting 45 second light frames. You did not mention what ISO you used. I went 800, but 1600 for your camera should be fine. Here is a site that will show you a graph of read noise. https://www.photonstophotos.net/Charts/RN_e.htm. Pick an ISO where the curve starts to flatten. I looked at your model and 800-1600 should suffice.

The other important thing with the darks, flats and bias frames is to make sure you capture them under the same temperature conditions as your light frames.

As far as processing, your chosen software is different than I use (other than Deep Sky Stacker, which I have replaced with the Pixinsight) so not sure I con be much help. Except I will echo a suggestion above to get Starnet++. When I started I used Nico Caver's videos as a guideline. Here is his Siril/GIMP workflow: https://www.youtube.com/watch?v=ambUmZLOeSs&t=0s. It includes a Starnet++ section.

HTH

Hello!

I really didn’t expect to get so many detailed comments! Thank you for writing, and you have a lot of great advice. Your andromeda picture looks crazy good, especially with only an hour and a half of total exposure time!

Once again, thank you, and i look forward to using the advice and seeing how it turns out.

Respectful Supportive

dkamen

Mar 5, 2023

Hi,

Did you use flats and darks?

Hello,

I have just taken some, and will try to see if that makes a difference. I may or may not make an update, as i tend to forget fast haha. Thanks.

Dark flats too. Calibration will help with the color banding and the vignetting, which in turn allows better background removal.

You should use at least ten darks (ISO and duration equal to your lights), 20-30 flats of at least 1 second (ISO and f/number equal to your lights, histogram peaking at the middle) and 20-30 dark flats (ISO and duration equal to the flats). If the result is too noisy, use more.

Well Written Helpful Concise

Maltasar_

Topic starter

Mar 6, 2023

Hi,

Did you use flats and darks?

Hello, i have just updated the imgur link in my original post. There is now two pictures. There is a slight editing error in the new picture (the “after” one), where it is a bit orange down-left of the galaxy when it shouldn’t be.

It is a pretty significant difference, and that is just your advice, so im looking forward to using all of the other advice i have gotten.