Can't seem to get the colours right

Questions and answers about processing in StarTools and how to accomplish certain tasks.
szymon
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Location: London

Can't seem to get the colours right

Post by szymon »

Hi there,

So I have some data -- there's not a lot of it, a total of 9x300s Ha and Oiii and 6x300s of Sii, but enough nebulosity visible for me to combine it in a hubble-esque pallet in other software. However I can't seem to get it right in StarTools!

I like the framing of the two nebula and want to collect more data (if the clouds hold off then maybe tonight), but I really need to learn to process it. Anyone able to help? Data is here:

https://www.dropbox.com/s/lifeln5ewx8u6bm/data.zip?dl=0

Best I can come up with (awful!) is this:
NewComposite_small.jpg
NewComposite_small.jpg (245.45 KiB) Viewed 2861 times
I've attached the log as a zip (well this is a log, I've tried many things many times!

-simon
Attachments
startools.zip
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admin
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Re: Can't seem to get the colours right

Post by admin »

Hi Simon,

It should be a simple matter of color balancing?
Start off with the Hubble preset. If the nebulosity is (too) green, simply reduce green.
Too little red? Increase it (switch "Bias Slider Mode" to "Sliders Increase Color Bias").
NewComposite.jpg
NewComposite.jpg (264.31 KiB) Viewed 2844 times
--- Bin
Parameter [Scale] set to [(scale/noise reduction 25.00%)/(1600.00%)/(+4.00 bits)]
--- Auto Develop
--- Crop
Parameter [X1] set to [43 pixels]
Parameter [Y1] set to [22 pixels]
Parameter [X2] set to [1342 pixels (-18)]
Parameter [Y2] set to [892 pixels (-20)]
Image size is 1299 x 870
--- Wipe
Vignetting preset
Parameter [Dark Anomaly Filter] set to [4 pixels]
Parameter [Corner Aggressiveness] set to [97 %]
--- Auto Develop
Parameter [Ignore Fine Detail <] set to [7.5 pixels]
Parameter [RoI X1] set to [329 pixels]
Parameter [RoI Y1] set to [586 pixels]
Parameter [RoI X2] set to [357 pixels (-942)]
Parameter [RoI Y2] set to [745 pixels (-125)]
--- Color
Huble preset
Parameter [Saturation Amount] set to [500 %]
Parameter [Green Bias Increase] set to [1.14]
Parameter [Red Bias Increase] set to [3.13]
--- Wavelet De-Noise
Parameter [Grain Size] set to [7.5 pixels]
Ivo Jager
StarTools creator and astronomy enthusiast
szymon
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Joined: Fri Jul 05, 2019 11:33 am
Location: London

Re: Can't seem to get the colours right

Post by szymon »

Ok so that's "sort of" my problem. When I get the DSO looking right, the stars are all wrong -- and vice versa. In your example the stars are very red!

I guess that kind of makes sense, because the image is made up out of the same colours being representing the Ha, Oiii and Sii channels, and there's no more data there, so there won't be any 'white' stars. So what's the solution to pull out the stars as white? Get some Luminance data and feed it in also?
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Re: Can't seem to get the colours right

Post by admin »

Magenta stars are a typical feature of a SHO image. Some people layer in RGB stars, others desaturate the stars, some just leave them in.
A quick and easy way to desaturate them, is to put them into a mask, launch the Filter module, set Filter Mod to Fringe Killer and then keep clicking on any magenta color you don't like until the color is gone.
Ivo Jager
StarTools creator and astronomy enthusiast
szymon
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Joined: Fri Jul 05, 2019 11:33 am
Location: London

Re: Can't seem to get the colours right

Post by szymon »

admin wrote:Magenta stars are a typical feature of a SHO image. Some people layer in RGB stars, others desaturate the stars, some just leave them in.
A quick and easy way to desaturate them, is to put them into a mask, launch the Filter module, set Filter Mod to Fringe Killer and then keep clicking on any magenta color you don't like until the color is gone.
Ahhh, I didn't realise that people process them manually. Thank you!
Rkonrad
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Joined: Sun Feb 07, 2016 2:55 am

Re: Can't seem to get the colours right

Post by Rkonrad »

Hi szymon,

I have spent a lot of fun time working with your data and decided, for me, I got the best results by going Bi-Colour which eliminated the S11 data. I still have trouble accessing my log file unless I trim it immediately after processing which I haven't done. In a nutshell, I used the HA as the luminance as this has is by far the best detail. I had tried loading HA luminance and then HA-red, Oiii-green and Oiii-blue but I couldn't get any visible Oiii to show in the centre of the 2 objects. So instead I processed the HA and Oiii separately and then loaded them, processed, in the LRGB module of StarTools 1.4 version ( I couldn't load them with 1.5 - separate post I think).

First, while linear, I binned them to default, autodev with focus on the top nebula and roi set at 100%. This gives nebulocity throughout the image. Soon after, I further binned once again (default) reducing the original image to 1600% overall. I made sure the image had sufficient contrast and detail before this as binning to this degree causes some blurring. The Oiii data required less processing as it was used for colour. I masked the emission areas and did life-isolate to emphasize. I then combined them then removed the stars.

For the stars to have a variety of colour (not accurate though), I loaded new data as LRGB with ha-l, ha-r, g-s11, b-O111 then mildly stretched , deconvoluted, colour (selected adjustments), denoise, and finally removed the stars. I resized the original nebula layer (in GIMP) to the star layer and combined them (StarTools).

Let me know if you need anymore information, let me know! - sorry this may be hard to follow.

https://www.flickr.com/gp/rkonrad/JA36xD

Cheers Richard
szymon
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Re: Can't seem to get the colours right

Post by szymon »

Oh wow. That's with my data? That's an incredibly beautiful image!

I really don't follow your processing steps, I think I'm going to have to go through slowly bit by bit and understand exactly what you did to make it look like that. Thank you so much for working with my data :-)
Rkonrad
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Re: Can't seem to get the colours right

Post by Rkonrad »

I'll send a video in the next week or 2. Hopefully that will help.

Cheers Richard
happy-kat
Posts: 237
Joined: Sun Feb 01, 2015 11:31 am

Re: Can't seem to get the colours right

Post by happy-kat »

That's really impressive processing, wow.
szymon
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Joined: Fri Jul 05, 2019 11:33 am
Location: London

Re: Can't seem to get the colours right

Post by szymon »

A video would be awesome :-)
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