Planetary images and LRGB stacks

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

Planetary images and LRGB stacks

Postby Amaranthus » Mon May 26, 2014 6:15 am

I'm gradually climbing the StarTools learning curve (and enjoying it) - I've read the unofficial version of the latest PDF manual, watched all the vid tutorials, and read around on the forum a bit. Two things that are still a little unclear:

1. I've done some planetary imaging and stacked in Autostakkert! (it's fast). I was thinking of using wavelet sharpen in Registax to enhance my images, but maybe StarTools would offer a better route. Has anyone done any planetary image enhancement with StarTools? I assume that if I can do this, I'd use the unsharpened image from AS! as the basis.

2. I've ordered a mono CCD, so am about to enter the world of LRGB imaging. Fun! But, something I'm sure is obvious but am not clear about - should I stack all each of the L, R, G and B channels in DSS separately, and then use the LRGB load in StarTools? Or should I stack them all in DSS before bringing them across? (if the former, I'm not sure how well they'd be aligned). Forgive my ignorance on this matter!

By the way Ivo, I'm astounded how good a product you are your small team have made of StarTools. Unbelievable processing power and flexibility at a low cost. Great work.
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Re: Planetary images and LRGB stacks

Postby admin » Mon May 26, 2014 7:37 am

Amaranthus wrote:1. I've done some planetary imaging and stacked in Autostakkert! (it's fast). I was thinking of using wavelet sharpen in Registax to enhance my images, but maybe StarTools would offer a better route. Has anyone done any planetary image enhancement with StarTools? I assume that if I can do this, I'd use the unsharpened image from AS! as the basis.

Yep, the latter is correct. StarTools offers some interesting tools for planetary procesing as well. If your image is from a video source, load the image as 'modified' and let StarTools undo the stretching so that Tracking can be switched on.

2. I've ordered a mono CCD, so am about to enter the world of LRGB imaging. Fun! But, something I'm sure is obvious but am not clear about - should I stack all each of the L, R, G and B channels in DSS separately, and then use the LRGB load in StarTools? Or should I stack them all in DSS before bringing them across? (if the former, I'm not sure how well they'd be aligned). Forgive my ignorance on this matter!

Oooers! Exciting! :D
Yes, stack L, R, G and B separately, but use one of the stacks as a reference (so that all the stars are nicely aligned across all channels/stacks). You can then load them into the LRGB module. You can even make a synthetic luminance by adding the color data to your luminance data (this obiously only works if luminance and colour data are both the same resolution).

By the way Ivo, I'm astounded how good a product you are your small team have made of StarTools. Unbelievable processing power and flexibility at a low cost. Great work.

It means a lot - thank you! :obscene-drinkingcheers:
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Re: Planetary images and LRGB stacks

Postby Amaranthus » Mon May 26, 2014 8:07 am

Thanks Ivo for the quick response and the advice about LRGB. I should have thought about a reference frame - makes perfect sense in hindsight.

I'm using a Neximage 5 planetary camera for my captures, typically capturing 5-10K frames at 5-15 fps. I'll try to get AS!2 to keep the output as 'virgin' as possible (if anyone has any tips on this, please let me know!). I'll post up a StarTools-proccessed image when I've got an example to show off (I have plenty of videos of Mars, Saturn and the Moon now archived, so lots of raw material to start mucking about with).
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Re: Planetary images and LRGB stacks

Postby admin » Mon May 26, 2014 9:06 am

Amaranthus wrote:Thanks Ivo for the quick response and the advice about LRGB. I should have thought about a reference frame - makes perfect sense in hindsight.

I'm using a Neximage 5 planetary camera for my captures, typically capturing 5-10K frames at 5-15 fps. I'll try to get AS!2 to keep the output as 'virgin' as possible (if anyone has any tips on this, please let me know!). I'll post up a StarTools-proccessed image when I've got an example to show off (I have plenty of videos of Mars, Saturn and the Moon now archived, so lots of raw material to start mucking about with).

Nice! Looking forward to your results.
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Re: Planetary images and LRGB stacks

Postby Amaranthus » Mon May 26, 2014 1:24 pm

I've been trying some StarTools planetary work tonight, with limited success. Looks like I might need some initial guidance.

For each planet, the file was the result of 500 best frames out of 7000, stacked in AS!2, with brightness normalization turned off. The 4 images are:
1. AS!2 output (base file)
2. Same stack but allowing AS!2 to normalize and sharpen, and then I colour balanced/contrasted in Paint.NET
3. File #1 run through StarTools, with no attempt to reverse stretching.
4. As per #3, but with reverse stretching and tracking (posted for Mars only)

Attached are the 'base' TIF files for Mars and Saturn. In the next two posts I'll put up the Mars #2, #3 & #4 and Saturn #2 and #3.

Here is a JPG snapshot of them all, for illustration.
Planets_May.JPG
Planets_May.JPG (36.67 KiB) Viewed 4184 times


To my eye, #2 looks by far the best, in both Mars and Saturn cases, yet really, involves very simple post-processing (AS!2 sharpening and brightness adjustment, then a few touch ups which took 5 min in Paint.NET). But I'm sure I'm not getting the most out of what StarTools can do with these base files, hence the call for help! In particular, I found that reversing the stretch and the autodeveloping led to highly overexposed images, which meant that I did a milder stretch using Dev. But it still didn't work out great - I couldn't get the same level of wavelet sharpness no matter what I did for either planet, and for Mars, the darker regions were overblown...
Attachments
Saturn_14May_Neximage.tif
Saturn_14May_Neximage.tif (189.17 KiB) Viewed 4184 times
1-Mars_11May_Neximage.tif
1-Mars_11May_Neximage.tif (54.17 KiB) Viewed 4184 times
Last edited by Amaranthus on Mon May 26, 2014 1:43 pm, edited 3 times in total.
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Re: Planetary images and LRGB stacks

Postby Amaranthus » Mon May 26, 2014 1:26 pm

Attached are the 3 processed Mars files (note that for #4, I also cropped it tightly, so it seems a little smaller [no binning though])
Attachments
Mars_11May_ST.tiff
Mars_11May_ST.tiff (30.97 KiB) Viewed 4185 times
Mars_11May_ST_nostretch.tiff
Mars_11May_ST_nostretch.tiff (54.18 KiB) Viewed 4185 times
Mars_11May_PaintNET.tif
Mars_11May_PaintNET.tif (15.04 KiB) Viewed 4185 times
Last edited by Amaranthus on Mon May 26, 2014 1:37 pm, edited 1 time in total.
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Re: Planetary images and LRGB stacks

Postby Amaranthus » Mon May 26, 2014 1:28 pm

And attached here are the 2 processed Saturn files, #2 & #3 (I didn't post one for Saturn with reversed stretching, as it looked horribly overexposed)
Attachments
Saturn_14May_ST.tiff
Saturn_14May_ST.tiff (189.18 KiB) Viewed 4185 times
Saturn_14May_PaintNET.tif
Saturn_14May_PaintNET.tif (41.94 KiB) Viewed 4185 times
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Re: Planetary images and LRGB stacks

Postby admin » Tue May 27, 2014 1:15 am

Nice!
I should've given you some more instructions to make the most of Planetary in StarTools...

When loading a stretched image from a video source or JPEG and choosing to reverse the stretch, StarTools will apply a reverse gamma correction before switching Tracking on.

This is what I did for Mars - tweak to taste obviously!
--- Develop
This will redo that gamma stretch so you get the original image (but now Tracking also knows what the image looked like when it was linear!).
Parameter [Gamma] set to [2.20]
--- Deconvolution
For planetary imaging, deconvolution is almost always very useful - it (to a point) reverses some of the adverse effects of poor seeing.
Manually generate a mask with just the planet in it (e.g. not the surrounding space).
Keep parameter [Image Type] set to [Deep Space]
Parameter [Radius] set to [4.3 pixels]
--- Wavelet Sharpen
Set Parameter [Intelligent Enhance] to [No], letting StarTools know that we want to go beyond what it recommends given the noisiness of the data.
Parameter [Scale 1] set to [100 %]
Parameter [Scale 2] set to [100 %]
Parameter [Scale 3] set to [100 %]
Parameter [Scale 4] set to [100 %]
Parameter [Scale 5] set to [100 %]
Parameter [Amount] set to [384 %]
Parameter [Small Detail Bias] set to [94 %]
--- Color
With both Mars and Saturn, it appears there is some chromatic aberration that causes some blue casts.
Nevertheless, these were my color settings;
Parameter [Style] set to [Artistic, Detail Aware]
Parameter [LRGB Method Emulation] set to [RGB Ratio, CIELab Luminance Retention]
Parameter [Dark Saturation] set to [1.00]
Parameter [Saturation Amount] set to [282 %]
Parameter [Green Bias Reduce] set to [4.82]
Parameter [Red Bias Reduce] set to [5.98]

1-Mars_11May_Neximage_ST.png
1-Mars_11May_Neximage_ST.png (7.95 KiB) Viewed 4174 times


Now for Saturn;
--- Develop
Same deal - redoing the 2.2 gamma stretch that StarTools undid so it was able to get to the linear version of the data;
Parameter [Gamma] set to [2.20]
Parameter [Dark Anomaly Filter] set to [8.7 pixels]
--- Deconvolution
Same thing - just select the planet and its rings;
Parameter [Radius] set to [5.0 pixels]
Parameter [Iterations] set to [13]
Parameter [Regularization] set to [0.91 (noisier, extra detail)]
--- Wavelet Sharpen
Parameter [Intelligent Enhance] set to [Yes]
Parameter [Amount] set to [172 %]
Parameter [Small Detail Bias] set to [96 %]
--- Color
Parameter [Style] set to [Artistic, Detail Aware]
Parameter [LRGB Method Emulation] set to [Straight CIELab Luminance Retention]
Parameter [Dark Saturation] set to [1.00]
Parameter [Bright Saturation] set to [Full]
Parameter [Saturation Amount] set to [600 %]
Parameter [Green Bias Reduce] set to [3.11]
Parameter [Red Bias Reduce] set to [2.49]

Saturn_14May_Neximage_ST.png
Saturn_14May_Neximage_ST.png (33.02 KiB) Viewed 4174 times


Tweak to taste and apply other procedures as you see fit of course!
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Re: Planetary images and LRGB stacks

Postby Amaranthus » Tue May 27, 2014 1:39 am

Wowee, they look absolutely fantastic! That's terrific Ivo -- not only for how those images look, but also for the general workplan to adopt and tweak in the future. I hope it helps other planetary imagers out there.

There should be little CA in the images -- they were taken with an 8" SCT at f/10 (no FR, no PM, so little intervening glass!). Anyway, I'll have another go tonight based on your guide, and then also post up the final results on IIS. Who knows, we may get some more planetary guys trying StarTools -- not just for DSOs, eh!
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