Help - Search - Members - Calendar
Full Version: Dawn's 8 color filters
Unmanned Spaceflight.com > Other Missions > Cometary and Asteroid Missions > Dawn
Antdoghalo
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?
mcaplinger
QUOTE (Antdoghalo @ Apr 14 2022, 05:19 PM) *
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.
Antdoghalo
For an RGB composite image, would I use the F3 or the F7 filter for the red?
fredk
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.
djellison
Depends on your intentions…..For a crude, approximate ‘true color’ (whatever that means) image - use F1,2,3.
Antdoghalo
When I try this in Gimp, It's either really blue or its somewhat green, not pinkish grey with bluish spots.
djellison
What is your pipeline before throwing images in to gimp?

Are you using radiometric calibration?

Antdoghalo
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?
djellison
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.
mcaplinger
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
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2024 Invision Power Services, Inc.