Shrinking stars

Questions and answers about processing in StarTools and how to accomplish certain tasks.

Shrinking stars

Postby elpajare » Tue Jun 04, 2019 4:35 pm

In the globular and open clusters with many stars I would like to be able to shrink them to increase the detail but without losing brightness

Is there any way to do it?

Thank you
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Re: Shrinking stars

Postby Rkonrad » Tue Jun 04, 2019 7:58 pm

Without seeing your example it's hard for me to advise - "reveal core" under HDR is a good tool for globular clusters. This will give you detail but not brightness. You could follow the action with a default "life". You could also try "flux" but be sparing. Hope that helps!

Cheers

Richard
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Re: Shrinking stars

Postby elpajare » Wed Jun 05, 2019 3:28 pm

Thanks for the reply.

Some of the ideas I have already put into practice but it always seems to me that I could do something else.
I attach a file from an IMX294 camera without trying to invite someone who has time to waste to process it and show the result.
My photos are short exposure (EAA-Videoastronomy) so do not expect a lot of data but I would like to know the limit of this type of photos and nothing better than a veteran of the forum who knows more and better the program to help me.

Thanks in advance to everyone

https://drive.google.com/open?id=1_tV8u ... DOlKwxOQWU
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Re: Shrinking stars

Postby Rkonrad » Wed Jun 05, 2019 7:41 pm

Thanks- but I think we will need the original stacked tiff (raw image)to process. You sent a jpg which wouldn't work.

Cheers

Richard
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Re: Shrinking stars

Postby elpajare » Thu Jun 06, 2019 6:14 am

This is one of the rare things of Startools, my camera stacks and records in jpg and this image I open it without problems with Startools (???)

This is the screenshot that I get, you will see that the file is in jpg.

I do not know what explanation he has ...
Attachments
Captura de pantalla 2019-06-06 a las 8.10.53.png
Captura de pantalla 2019-06-06 a las 8.10.53.png (168.07 KiB) Viewed 941 times
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Re: Shrinking stars

Postby elpajare » Thu Jun 06, 2019 6:37 am

And this is the link to the file Im using now with Startools with any problem. I can open it... :confusion-shrug:

https://drive.google.com/open?id=1Gh_ph ... fLizrRcacm
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Re: Shrinking stars

Postby happy-kat » Thu Jun 06, 2019 11:14 am

Hi
If you want to use modules like Wipe then you would need to be able to turn on tracking, to allow tracking you would select the left option.
If you do not need tracking or the wipe module then select the right option.

Try both options and see which you get best results from with your data.
Last edited by happy-kat on Sat Jun 08, 2019 1:00 pm, edited 1 time in total.
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Re: Shrinking stars

Postby admin » Fri Jun 07, 2019 2:59 am

Hi,

Would you be able to send us some more information about your camera? (e.g. manufacturer, model, etc.)

If possible, you should avoid JPEGs and in-camera stacking at all times. The JPEG format is only 8-bit, does not allow for faint detail, has already been stretched, has lossy compression applied and - usually - has all sorts of other operations applied that make detail recovery, color calibration, light pollution removal, etc. impossible.

If you have absolutely no other choice, you can choose "Attempt to reverse stretch". This will undo the sRGB stretch that JPEG encoding applies, making the data linear again (in theory). This will allow you to engage Tracking mode and use all the modules that only make "mathematical sense" when used on linear data.

All that said, you can use the Magic module to shrink you stars, even with post-processed JPEGs.
You first need to make a mask, that contains the stars that you want to shrink. If you have "fat" stars with overexposed cores, those are usually the stars you'll want to target.
Mas > Auto, set 'Selection Mode' to 'Highlights > Threshold', then choose a brightness 'Threshold' above which you want to select pixels. For example 85%.
Click 'Do', and you will now have a mask overexposed star cores. You will want to 'Grow' the mask a little (click 'Grow' a few times), to include more of the stars.
Now 'Keep' your mask. You should now be ready to use it in the Magic module (use 'Iterations' to shrink more);

For example, you can go from this;
1.jpg
1.jpg (156.86 KiB) Viewed 918 times


To this;
2.jpg
2.jpg (140.45 KiB) Viewed 918 times


Do let us know your camera's specs. Hope this helps in the meantime!
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Re: Shrinking stars

Postby elpajare » Fri Jun 07, 2019 7:36 am

Thank you very much for the explanation, now I have the process clear. The final result is good enough for me.

The camera is from Risingcam and has the IMX294 chip uncooled. I use the native software of the camera for the capture and stack of the images and I record each photograph in jpg because it occupies me less space. The expo I do serve is very short, between a few seconds and 30 seconds maximum, I dont make out any guiding. It is what is usually called EAA or videoastronomy.

I have been using Startools for a long time and all my photos have been treated with this program that I am very happy with it and I always recommend to my friends. Every day I learn something else new from it..... :thumbsup:

These are some of the examples I get with a TSOptics RC8 "+ IMX294 and a later treatment with Startools, they are simple photos without any pretense that they are authentic "astrophotos". In case someone wants to see what it's about... :)

https://estrellasygalaxiasdesdecasa.blogspot.com/

https://telescopius.com/profile/elpajare
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Re: Shrinking stars

Postby admin » Sun Jun 09, 2019 1:52 am

elpajare wrote:Thank you very much for the explanation, now I have the process clear. The final result is good enough for me.

The camera is from Risingcam and has the IMX294 chip uncooled. I use the native software of the camera for the capture and stack of the images and I record each photograph in jpg because it occupies me less space. The expo I do serve is very short, between a few seconds and 30 seconds maximum, I dont make out any guiding. It is what is usually called EAA or videoastronomy.

I have been using Startools for a long time and all my photos have been treated with this program that I am very happy with it and I always recommend to my friends. Every day I learn something else new from it..... :thumbsup:

These are some of the examples I get with a TSOptics RC8 "+ IMX294 and a later treatment with Startools, they are simple photos without any pretense that they are authentic "astrophotos". In case someone wants to see what it's about... :)

https://estrellasygalaxiasdesdecasa.blogspot.com/

https://telescopius.com/profile/elpajare


Understood. It's great to see how much you are capturing, even with JPEG output. And I'm glad to hear you are happy with what you are producing - in the end that's the most important.
We don't all have the time (or even patience) to spend under pristine night skies. Yet you are still capturing stuff amateur astrophotographers 30-40 years ago could have only dreamed of. :thumbsup:
Just as important are the stories behind these objects (I love how you have those on your blog). Sometimes processing can help substantiate these stories (for example color temperature).

If you haven't seen this video yet, it explains why it's better to do as much as possible (Contrast, Sharp, Life, HDR) with Tracking still on, and why it is better to turn it off as late in your processing flow as you can (for example, at 1:00, it shows how Tracking actually remembers the difference between noisy shadows and not-so-noisy shadows, whereas this information is lost with Tracking off).

Hope this helps,
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