Dawn's 8 color filters, What is each filter |
Dawn's 8 color filters, What is each filter |
Apr 15 2022, 01:19 AM
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#1
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Member Group: Members Posts: 246 Joined: 13-October 09 From: Olympus Mons Member No.: 4972 |
I am trying to figure out the color of Ceres and in the PDS, I have come upon the fact that Dawn used 8 color filters but I don't know which ones were RGB and what the other 5 were. Does anyone have leads on this info?
-------------------- "Thats no moon... IT'S A TRAP!"
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Apr 15 2022, 01:36 AM
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#2
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Senior Member Group: Members Posts: 2547 Joined: 13-September 05 Member No.: 497 |
I am trying to figure out the color of Ceres and in the PDS, I have come upon the fact that Dawn used 8 color filters but I don't know which ones were RGB and what the other 5 were. Does anyone have leads on this info? https://sbnarchive.psi.edu/pds3/dawn/fc/DWN...IS_20160815.PDF page 13-14. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Apr 15 2022, 12:19 PM
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#3
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Member Group: Members Posts: 246 Joined: 13-October 09 From: Olympus Mons Member No.: 4972 |
For an RGB composite image, would I use the F3 or the F7 filter for the red?
-------------------- "Thats no moon... IT'S A TRAP!"
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Apr 15 2022, 02:18 PM
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#4
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Senior Member Group: Members Posts: 4259 Joined: 17-January 05 Member No.: 152 |
749nm is pretty long for red - our cones don't respond much out there.
Presumably you're going to be adjusting colours by eye anyway, and not doing a proper transformation from raw colour space to sRGB or whatever, so it probably doesn't matter too much. |
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Apr 15 2022, 02:19 PM
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#5
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Founder Group: Chairman Posts: 14444 Joined: 8-February 04 Member No.: 1 |
Depends on your intentions…..For a crude, approximate ‘true color’ (whatever that means) image - use F1,2,3.
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Apr 15 2022, 07:53 PM
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#6
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Member Group: Members Posts: 246 Joined: 13-October 09 From: Olympus Mons Member No.: 4972 |
When I try this in Gimp, It's either really blue or its somewhat green, not pinkish grey with bluish spots.
-------------------- "Thats no moon... IT'S A TRAP!"
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Apr 15 2022, 10:28 PM
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#7
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Founder Group: Chairman Posts: 14444 Joined: 8-February 04 Member No.: 1 |
What is your pipeline before throwing images in to gimp?
Are you using radiometric calibration? |
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Apr 16 2022, 12:55 AM
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#8
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Member Group: Members Posts: 246 Joined: 13-October 09 From: Olympus Mons Member No.: 4972 |
I just throw these in with the indicated channels: https://sbnarchive.psi.edu/pds3/dawn/fc/DWNCHFFC2_2/EXTRAS/
Is there a process I need to edit them with or do they need to be the converted img files? -------------------- "Thats no moon... IT'S A TRAP!"
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Apr 16 2022, 03:42 AM
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#9
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Founder Group: Chairman Posts: 14444 Joined: 8-February 04 Member No.: 1 |
OK - that's just projected maps in different channels. There's no radiometric calibration there as such - you're not going to get the colors you're expecting.
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Apr 16 2022, 04:59 PM
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#10
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Senior Member Group: Members Posts: 2547 Joined: 13-September 05 Member No.: 497 |
Ceres is basically gray. If you're just messing around for fun, you can simply adjust the color channel brightness until the overall color is gray, and then change the contrast to see if you can bring up subtle color differences.
To really do science, you have to use and understand the radiometrically-calibrated image products. Or you could just read https://www.researchgate.net/publication/31...g_Camera_Images -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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