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First Light ASI2600MC Pro - Crescent Nebula

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#1 cloudyeverynight

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Posted 21 May 2024 - 12:02 PM

Wow! I couldn’t be happier with my session from last night. I just finished post processing. I'm going to do another stacking session tomorrow to work on some different tools and techniques and see what else I can get out of this initial data set. It's only 3 hours of integration so I think I will go for a couple more nights (if the skies will permit me). My Canon EOS-R was a real trooper the last couple years but man, no comparison to a real astro-cam... Anyway, critiques and/or things I can improve upon all always welcome!

 

  • Main scope - Meade 6000 115mm f/7 ED APO triplet refractor w/ Explore Scientific Field Flattener
  • Antlia ALP-T Dualband 5nm HA & OIII Filter
  • Mount - AM5
  • Guide camera - ASI220 mini cam
  • Guide scope - WO Z61
  • ASIAIR Plus

 

  • 300s X 53 lights, 80 bias, 40flats, 40 darks
  • SIRIL, StarNet, Affinity Photo
  • 2600MC settings: cooling -10c, fan half speed, gain 100, dew heater on
  • ASI220 settings: gain 127, 4s exposures

High res images including the starless processed image HERE

 

Crescent Nebula star recomposition result SMALL.jpg


Edited by cloudyeverynight, 21 May 2024 - 12:04 PM.

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#2 Zambiadarkskies

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Posted 21 May 2024 - 12:29 PM

Great image. Congratulations on it and the new camera.  

 

My only comments are:  my AM5 likes quite fast paced guiding (all harmonics do).  I find 1s guide exposures as a good compromise. You are using a 220 (and an amazing "guiding" scope) so you should be able to dial that guiding exposure time back by a lot and be fine.  There is quite a difference in sky background, the lower right hand corner has a very different colour cast, which I am pretty sure is a gradient - maybe the moon or light pollution?  

 

I feel that background tools (I am not familiar with siril) would really help and dropping the guiding cadence you might find helps things in general.   You might want to look into Graxpert which works really well for gradients.  



#3 bsturges

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Posted 21 May 2024 - 12:45 PM

Fantastic- it really is a whole different ballgame with a cooled astro camera. About that blue glow in the lower right corner: you may want to check your flatfield technique rather than forcing software to fix data with some kind of gradient.



#4 cloudyeverynight

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Posted 21 May 2024 - 12:48 PM

Great image. Congratulations on it and the new camera.  

 

My only comments are:  my AM5 likes quite fast paced guiding (all harmonics do).  I find 1s guide exposures as a good compromise. You are using a 220 (and an amazing "guiding" scope) so you should be able to dial that guiding exposure time back by a lot and be fine.  There is quite a difference in sky background, the lower right hand corner has a very different colour cast, which I am pretty sure is a gradient - maybe the moon or light pollution?  

 

I feel that background tools (I am not familiar with siril) would really help and dropping the guiding cadence you might find helps things in general.   You might want to look into Graxpert which works really well for gradients.  

Thank you for the tips. The Moon was a pain last night for sure and I'm also dealing with bortle 6 NJ light polluted skies...

 

My plan is to go another round and capture the same exact way but on moonless night and without the narrow band filter and process everything together. That should get me up to around 5-6 hours or so of integration.

 

Hoping to get rid of that gradient. Normally SIRIL does that extremely well but it was giving me a bit of trouble this time, not sure why.  Anyway I'd also like to get some of the other colors in there to pop a bit more.


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#5 cloudyeverynight

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Posted 21 May 2024 - 12:54 PM

Fantastic- it really is a whole different ballgame with a cooled astro camera. About that blue glow in the lower right corner: you may want to check your flatfield technique rather than forcing software to fix data with some kind of gradient.

Interesting you mention the flats. They looked pretty weird to me. I ended up taking a lot more than usual because of the way looked. I used the tried and true white t-shirt technique which normally gives good results. Later tonight when I have time I'll post a sample flat from a set I did not use and one from a set I did use for this image. Thanks!


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#6 Desertanimal

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Posted 21 May 2024 - 03:48 PM

Great shot! Excellent capture!

#7 rj144

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Posted 21 May 2024 - 05:03 PM

Great shot!

 

When I went from a DSLR to a astrocam, there was a huge difference too.  DSLR's are decent for starting and ok for some targets but astrocams are so much better.

 

There's a user on the Reddit astro sub, who when folks have money to upgrade to an astrocam, always tells them not to and just use their DSLR.  It kind of drives me nuts sometimes.  :)



#8 Cryhavoc38

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Posted 21 May 2024 - 10:48 PM

Download graxpert for your background extraction.

It has a very good AI plugin.

 

Stack in siril, then use graxpert for the background gradient work.

 

Also since you are using an AM5 mount, use 1 second exposures for your guide camera. 2 seconds max. The AM 5 works best with fast exposure guide camera settings.



#9 cloudyeverynight

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Posted 22 May 2024 - 03:31 AM

Download graxpert for your background extraction.

It has a very good AI plugin.

 

Stack in siril, then use graxpert for the background gradient work.

 

Also since you are using an AM5 mount, use 1 second exposures for your guide camera. 2 seconds max. The AM 5 works best with fast exposure guide camera settings.

I'm going to give Graxpert a try, thanks for the recommendation. Regarding the guiding, are you seeing something in that image that indicates a guiding issue? How would lowering the exposure time improve the subs? All 53 lights that were taken were free from detectable trailing (to my eye anyway). I'm just curious, thanks.



#10 cloudyeverynight

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Posted 22 May 2024 - 10:26 PM

Download graxpert for your background extraction.

Well, looks like GraXpert is pretty awesome... Thanks for the suggestion! Here is the latest version.

 

Crescent Nebula star recomposition result_GRAX V1.jpeg


Edited by cloudyeverynight, 22 May 2024 - 10:27 PM.

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#11 rj144

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Posted 22 May 2024 - 11:13 PM

Well, looks like GraXpert is pretty awesome... Thanks for the suggestion! Here is the latest version.

 

attachicon.gif Crescent Nebula star recomposition result_GRAX V1.jpeg

What algorithm were you using in Siril because technically the default algorithm for both is identical?  



#12 Cryhavoc38

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Posted 23 May 2024 - 01:34 AM

What algorithm were you using in Siril because technically the default algorithm for both is identical?  

I don't think that the current version of Siril has incorporated the latest Graxpert function such as the AI algo


Edited by Cryhavoc38, 23 May 2024 - 01:36 AM.


#13 Cryhavoc38

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Posted 23 May 2024 - 01:38 AM

I'm going to give Graxpert a try, thanks for the recommendation. Regarding the guiding, are you seeing something in that image that indicates a guiding issue? How would lowering the exposure time improve the subs? All 53 lights that were taken were free from detectable trailing (to my eye anyway). I'm just curious, thanks.

Not really, but the conventional thinking with strain wave mounts are that they really prefer faster guiding settings such as setting your guide cam exposure to 1 or 2 seconds.

I personally started out at 2 seconds and left it there for the past year.

 

Give it a go at 2 seconds the next time out.

it might help bring out a wee bit more detail and tighten up your stars.

 

btw, what does the asiair app say your average star size is in the above image?

Try shooting it again with 2 sec guide exposures, get a good focus and then hit the detect button on a preview screen. I think its the detect button on the left side of the screen.


Edited by Cryhavoc38, 23 May 2024 - 01:43 AM.


#14 cloudyeverynight

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Posted 23 May 2024 - 08:11 AM

Not really, but the conventional thinking with strain wave mounts are that they really prefer faster guiding settings such as setting your guide cam exposure to 1 or 2 seconds.

I personally started out at 2 seconds and left it there for the past year.

 

Give it a go at 2 seconds the next time out.

it might help bring out a wee bit more detail and tighten up your stars.

 

btw, what does the asiair app say your average star size is in the above image?

Try shooting it again with 2 sec guide exposures, get a good focus and then hit the detect button on a preview screen. I think its the detect button on the left side of the screen.

Hmm, I don't know. I'll check that out next time around.



#15 rj144

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Posted 23 May 2024 - 08:48 AM

I don't think that the current version of Siril has incorporated the latest Graxpert function such as the AI algo

The AI just places the points, but the algorithm is the same as placing the points manually in both.




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