ngc6888 at full moon

[alacant]

Hi everyone

Along with our cheepo UHC filter, this was doable probably because the moon was low toward Sagittarius. Unfortunately it flares bright stars toward the edges. I'm told I need to get the filter in front of the sensor, rather than on the telescope side of the cc. It's never straightforward...

Not keen on current processing trends; IMO, stars make the image. Leave them out and the image looks flat, lifeless...

Thanks for looking and do post your uhc images, especially if you had a go at full moon.

pn208 ~3h apilado: siril 1.3.0a. proc:st 1.9.557 hoo  oiii en nbaccent

 

Edited July 3, 2023 by alacant
translation

[DrMike]

Brilliant imaging. 

[AstroMuni]

24 minutes ago, alacant said:

Along with our cheepo UHC filter, this was doable probably because the moon was low toward Sagittarius. Unfortunately it flares bright stars toward the edges. I'm told I need to get the filter in front of the sensor, rather than on the telescope side of the cc. It's never straightforward...

Not keen on the current processing trends; IMO, stars make the image.

Thats a lovely image. What is your process flow in Siril?

[alacant]

3 hours ago, AstroMuni said:

process flow in Siril

The simplest possible.

Calibrate: light and flat frames offset removal only. No automated scripts. No darks. No extract Ha-Oiii stuff. No star processing or any other distraction. No nonsense!
Register: two pass 
Stack: sigma low 5 high 2

That's it. Cheers and HTH

Edited July 3, 2023 by alacant
translation

[FenderGreg]

Beautiful image!!

siril 1.3.0??

I had my first try at this last night but only got just over an hour n half before a storm came flying in!

Did you use background extraction in Siril? If so, how on such a nebula filled background? I’m more used to using the grid around a target than processing a ‘scenery’

[alacant]

22 hours ago, FenderGreg said:

siril 1.3.0??

Everyone can help by testing:

Latest git here.

22 hours ago, FenderGreg said:

Did you use background extraction in Siril?

We use Siril only for calibration, registration and stacking.

If you really do need to use bg-extract, simply put the points manually yourself to coincide with a few reasonably dark and well spaced patches. With a UHC, you'll probably find that you don't need to.

 

22 hours ago, FenderGreg said:

but only got just over an hour n half before a storm

Aww, pity. At this game, you need patience.

Cheers and thanks for your comment

Edited July 10, 2023 by alacant
git

[FenderGreg]

What’s the advantage of calibrating, registering and stacking the images yourself?

[bomberbaz]

On 03/07/2023 at 11:57, alacant said:

The simplest possible.

Calibrate: light and flat frames offset removal only. No automated scripts. No darks. No extract Ha-Oiii stuff. No star processing or any other distraction. No nonsense!
Register: two pass 
Stack: sigma low 5 high 2

Hello and thanks for the image and your explanations on process.

Am I right in thinking that your exclusion of darks is largely down to the fact you are imaging in narrowband or is there some other reason for exclusion?

Also can you explain 2 pass, I am not sure I follow?

Thanks for the help as I really like the simplicity angle of your imaging.

Steve

[AstroMuni]

10 hours ago, bomberbaz said:

Also can you explain 2 pass, I am not sure I follow?

This might help https://siril.readthedocs.io/en/latest/preprocessing/registration.html

[alacant]

11 hours ago, bomberbaz said:

exclusion of darks

Hi

Unless you have a camera which has sensor amplifier glow, we find that dark frames introduce more problems than they solve. That, added to the fact that with many cameras it is not possible to match the temperature of the dark and light frames leads us to the simplified approach. Perhaps best to try both and see which you prefer. No two cameras are alike so generalisations only go so far.

11 hours ago, bomberbaz said:

can you explain 2 pass

NP:

But as @AstroMunirecommends, a bit of rtfm goes a long way.

Cheers and HTH

Edited July 11, 2023 by alacant

[alacant]

17 hours ago, FenderGreg said:

What’s the advantage of calibrating, registering and stacking the images yourself?

Which alternatives did you have in mind?

Edited July 11, 2023 by alacant
cuál which what

[bomberbaz]

7 minutes ago, AstroMuni said:

This might help https://siril.readthedocs.io/en/latest/preprocessing/registration.html

I have visited this before and not had time to fully digest. 

Siril is a complex but very versatile programme. I think if I can put aside time to master the process, my results would definately improve.

6 hours ago, alacant said:

Hi

Unless you have a camera which has sensor amplifier glow, we find that dark frames introduce more problems than they solve. That, added to the fact that with many cameras it is not possible to match the temperature of the dark and light frames leads us to the simplified approach. Perhaps best to try both and see which you prefer. No two cameras are alike so generalisations only go so far.

Right of course, well my camera generates quite a bit of amp glow and as such darks are needed. I understand there are other methods (or am I thinking of flats) but I will continue to use darks and camera being cooled, these are easier to duplicate.

Cheers anyway, I shall look into the 2 pass method and reading the user guide a little more thoroughly.

Steve

[AstroMuni]

52 minutes ago, bomberbaz said:

I think if I can put aside time to master the process, my results would definately improve.

Luckily for us most of the default settings in Siril will get good results. Its only in the infrequent cases that we need to understand the options available to help get around it.

Edited July 11, 2023 by AstroMuni

[FenderGreg]

12 hours ago, alacant said:

Which alternatives did you have in mind?

I just run the pre loaded scripts at the moment which is surely so much quicker. But if you’re doing it all yourself, do you find an advantage of doing it that way?

[alacant]

Hi

So long as you understand what the script is doing, enabling you to troubleshoot should anything go wrong, and the results are acceptable to you, then perfect.
OTOH, using Siril manually takes only a few more clicks, plus you can use methods -such as our minimalist approach- for which there is no script; the operator is in control rather than the script.

Cheers

Edited July 12, 2023 by alacant