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Old 21-11-2023, 02:49 PM
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Benjamin (Ben)
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Jupiter colour issues

I've just begun the process of imaging Jupiter with the following setup:

8" f4 Skywatcher Newtonian
4x Powermate
ZWO ASI462MM
Astrodon 1.25" Gen 2 E-Series CCD RGB filters

The goal was to use what I had (the Newt and the filters) plus a few extra things (Powermate, camera) to capture planets, despite the smallish aperture.

I've been imaging using Sharpcap and get around 100fps for 45s, using a small ROI and hitting around 80% on the histogram for each channel. I use Sharpcap's solar system sequencer to get three RGB runs in a row, with a focus set before I begin (hard to see any difference with focus between each filter). I've then been running the Mono8 SER video files through Autostakkert, Registax (wavelet sharpening) and WinJUPOS. I use regular Derotation on each channel (Red, Green, Blue) and then RGB Derotation on the complied Red, Green and Blue images (saving images as TIFFs). It seems I'm getting some rather odd colours (see image), particularly in the dark bands. I wonder what might be causing the pink/maroon colour? Registax RGB balancing doesn't solve this and I've been working around it using a red colour mask in PixInsight, upping the green and lowering the blue.

The Astrodon filters have a clear gap between the Red and Green transmission peaks (to avoid light pollution) so I wonder if this lack of cross over is to blame? I've seen other images using Astrodon filters that don't seem to have this issue however, but have also heard mention, via a very imformative YouTube video, that Astrodon filters don't perform so well on planets. Perhaps for this reason? I've attached each sharpened RGB channel if that helps?

Would love any thoughts on this. Maybe I'm doing something wrong or missed a setting somewhere? Cheers.
Attached Thumbnails
Click for full-size image (2023-11-18-1005_6-Capture_Red_Jupiter_lapl5_ap73-RGB.jpeg)
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Click for full-size image (JupiterAGAIN.jpeg)
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Click for full-size image (Red.jpeg)
102.3 KB17 views
Click for full-size image (Green.jpeg)
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Click for full-size image (Blue.jpeg)
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  #2  
Old 21-11-2023, 06:58 PM
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Benjamin (Ben)
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May have answered my own question here. I decided to explore some custom channel mixes in PixInsight using pixel math. Turns out this got a closer to what I think the natural colour might be.

RED channel: RED
GREEN channel: 0.5*GREEN+0.5*RED
BLUE channel: 0.5*BLUE+0.5*GREEN

Very inelegant math but... ended up with the attached image without having to fart around with colour masks etc. and I could keep the moons.
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Click for full-size image (Jupter_FINAL.jpeg)
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Old 22-11-2023, 09:32 PM
Dave882 (David)
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Nice shots Ben and glad you found a good solution. I知 shooting with a asi462mc and find after derotation I lose colour and end up having to tinker with the curves /histogram. A bit frustrating and still trying to work out what I知 doing wrong
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Old 23-11-2023, 09:59 AM
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Quote:
Originally Posted by Dave882 View Post
Nice shots Ben and glad you found a good solution. I知 shooting with a asi462mc and find after derotation I lose colour and end up having to tinker with the curves /histogram. A bit frustrating and still trying to work out what I知 doing wrong
Losing colour altogether or odd hues? I知 not convinced I知 on top of winJULPOS yet so maybe that is an issue as well. The colour issue I知 having seems quite common (searching cloudy nights) but mostly this is through refractors. These folks blame chromatic aberration. While this isn稚 an issue with a Newtonian perhaps the lenses on my 4x Powermate are adding some kind of CA? Also lots of Astrodon filter images using a monochrome camera that don稚 seem to have issues which makes me more suspicious that my solution is not the whole (or correct) story. Anyway it wouldn稚 be astrophotography if we weren稚 tearing our hair about something!
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Old 27-11-2023, 07:12 PM
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And then you realize you壇 name the filters incorrectly in ASCOM.argh (I壇 swapped blue and green).
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