by Ann » Mon Apr 10, 2023 6:22 pm
Chris Peterson wrote: ↑Mon Apr 10, 2023 3:06 pm
Ann wrote: ↑Mon Apr 10, 2023 3:00 pm
Chris Peterson wrote: ↑Mon Apr 10, 2023 1:44 pm
I don't know if they're scientifically assigned or not. My objection is that there is no information about this image to be found, so it's essentially useless for anything other than admiring pretty colors. Not an image that should be accepted for APOD, IMO.
Chris, how do you assign scientific colors to a narrowband image?
Ann
The choice of mapping is critical to showing certain features. If that choice is carried out with that intent (as opposed to simple aesthetics) I'd very much call that "scientific". The Hubble palette, for instance, was not created for the purpose of making images "pretty". People who design or choose false color and pseudocolor palettes understand human vision, and why specific assignments make sense for specific information goals.
I get that. The Hubble palette usually shows OIII as blue, Hα as green and NII (or SII) as red. The wavelengths of Hα and NII (or SII) are both red and so similar that they would look identical in RGB images, but they do represent very different levels of ionization, and the Hubble palette makes them look very clearly different.
I still don't think that the Hubble palette is "scientific", but I can see that it is practical and useful.
Ann
[quote="Chris Peterson" post_id=330335 time=1681139189 user_id=117706]
[quote=Ann post_id=330334 time=1681138819 user_id=129702]
[quote="Chris Peterson" post_id=330332 time=1681134254 user_id=117706]
I don't know if they're scientifically assigned or not. My objection is that there is no information about this image to be found, so it's essentially useless for anything other than admiring pretty colors. Not an image that should be accepted for APOD, IMO.
[/quote]
Chris, how do you assign scientific colors to a narrowband image?
Ann
[/quote]
The choice of mapping is critical to showing certain features. If that choice is carried out with that intent (as opposed to simple aesthetics) I'd very much call that "scientific". The Hubble palette, for instance, was not created for the purpose of making images "pretty". People who design or choose false color and pseudocolor palettes understand human vision, and why specific assignments make sense for specific information goals.
[/quote]
I get that. The Hubble palette usually shows OIII as blue, Hα as green and NII (or SII) as red. The wavelengths of Hα and NII (or SII) are both red and so similar that they would look identical in RGB images, but they do represent very different levels of ionization, and the Hubble palette makes them look very clearly different.
I still don't think that the Hubble palette is "scientific", but I can see that it is practical and useful.
Ann