OSC Optolong l-eNhance colour

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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Re: OSC Optolong l-eNhance colour

Post by admin »

As for using the L-Enhance stack with a visual-spectrum stack; this is indeed absolutely possible and should yield very good results;

Detail of the L-Enhance stack with visual spectrum coloring of the visual-spectrum stack. @fmeireso; it is essentially a similar procedure to using Ha and visual spectrum data like we did in the Elf's thread on CloudyNights.

E.g. just use the L-Enhance stack as L, and the visual-spectrum stack as red, green and blue, while using "L, RGB" for "Luminance, Color".

You may want to experiment a bit in the Color module with the LRGB Emulation; the "RGB Ratio, CIELab Luminance Retention" setting for "LRGB Method Emulation" will likely produce a better result. That is because luminance and chrominance are not coming from the same dataset and are decoupled.
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Re: OSC Optolong l-eNhance colour

Post by firebrand18 »

Thanks Ivo, will certainly try this L-Enhance-UV/IR combo as you outlined. I assume when creating the two separate stacks in DSS you simply use a reference light frame from the first night's stack, add it to the 2nd night's stack as the reference frame but ensure it is unchecked; this should properly align and register all frames from both stacks.
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Re: OSC Optolong l-eNhance colour

Post by admin »

firebrand18 wrote: Sat Mar 06, 2021 2:51 am I assume when creating the two separate stacks in DSS you simply use a reference light frame from the first night's stack, add it to the 2nd night's stack as the reference frame but ensure it is unchecked; this should properly align and register all frames from both stacks.
Spot on! :thumbsup:
You may possibly get even better results by using the complete other stack as a reference, rather than just one of its frames.
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Re: OSC Optolong l-eNhance colour

Post by fmeireso »

Darn,


So this is the way in DSS to align 2 different stacks?

i used Siril ,because i did not knew better...
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Re: OSC Optolong l-eNhance colour

Post by firebrand18 »

Just ask Ivo...he knows everything! :bow-yellow:
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Re: OSC Optolong l-eNhance colour

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firebrand18 wrote: Mon Mar 08, 2021 8:56 pm everything
As my SO would attest to, though I may know a lot about a select few things, I am rather hopeless at most other things, including some very basic life skills. :lol:
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Re: OSC Optolong l-eNhance colour

Post by firebrand18 »

:D
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Re: OSC Optolong l-eNhance colour

Post by Stefan B »

Hi everbody!

Finally got some clear skies with the opportunity to test l-eNhance + broadband imaging/processing. I went for the Flaming Star nebula, which is maybe not the most suited target since it's not very rich in OIII, but it is high in the sky (for my latitude) and at least some hours of exposure per night were possible. Imaging resulted in about 8 hours of l-eNhance data and about 3 hours of broadband data. Both data sets were registered to the same sub frame (registering the second data set to the stack of the first set just doesn't work...) and the l-eNhance stack was used as a luminance layer, while broadband was assigned to RGB in the compose module. After working through the models this was the result:
Flamingstar-L+RGB_PS_small.jpg
Flamingstar-L+RGB_PS_small.jpg (148.29 KiB) Viewed 243 times
I am pretty happy with the amount of detail I got. For comparison I also made an HOO version which lacked the broadband chrominance information:
Flamingstar-HOO-PS-small.jpg
Flamingstar-HOO-PS-small.jpg (152.83 KiB) Viewed 243 times
The exact same processing was also used for another color rendition (H+[H+O]+O), resulting in this image:
Flamingstar-H(HO)O-PS-small.jpg
Flamingstar-H(HO)O-PS-small.jpg (185.56 KiB) Viewed 243 times
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Re: OSC Optolong l-eNhance colour

Post by Stefan B »

I found this rendition pretty pleasing but it lacked the RGB stars. So using the layer module and a star mask I tried to get the RGB stars from the first image into the H(HO)O rendition:
Flamingstar-H(HO)O-PS+RGB-small.jpg
Flamingstar-H(HO)O-PS+RGB-small.jpg (149.78 KiB) Viewed 242 times
Just for fun the RGB data was also processed to give a comparison to the narrowband luminance:
RGBonly-PS-small.jpg
RGBonly-PS-small.jpg (154.62 KiB) Viewed 242 times
Of course, this is not a fair comparison since the l-eNhance data contains more than twice the amount of exposure time. But I think one can cleary see that using narrow(er) band data as a luminance layer increases the amount of detail (okay, not very surprising, but I've never done that before). Using broadband as chrominance results in more natural colors which I really find missing in the HOO and H(HO)O versions. I think my favourite versions are the L(HaOIII)+RGB and the H(HO)O renditions with RGB stars :)

This has really been fun. Thanks, Ivo, for making this possible! :obscene-drinkingcheers:

Clear skies to everyone!
Stefan :mrgreen:
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Re: OSC Optolong l-eNhance colour

Post by Stefan B »

By the way, the scope used is a Sky-Watcher 150/750 (non-PDS) and the camera is a Canon EOS 1100Da. As a beginner I'm pretty amazed what is possible with a budget scope and an old DSLR, which can be bought used for under 200 EUR.
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