fsgregs wrote:Hi Fridger and everyone:
Today, I took the liberty of adjusting the color of the default
Titan surface and Titan clouds, to match the first color photo,
and adjusting the atmosphere to better match the photo.
Here is a screenshot from the surface, compared to the photo from Huygens
http://www.fsgregs.org/celestia/files/Huygens%20settings.JPGIf you like it, I'll upload it to Motherlode as an add-on.
Comments?
Frank
Frank,
yes with the new color information some next round of
approximation to reality should be possible. You might also
have noticed my own attempt in "users->t00fri's
Titan@Celestia" from yesterday morning.
There are two issues though:
1) There was NO accurate caption yet with ESA's published
color photo of Titan's surface! We have no idea on the basis
of how many filters the color has been reconstructed. I
suppose they use at best two (i.e. not a true R G B set). So
considerable uncertainty surely remains.
On the contrary, the color imaging of Titan's apparently more yellowish
/outer haze atmosphere/ done from Cassini is most probably
much closer to an accurate visual appearance. My outer Titan
clouds in Celestia-1.3.2 where matched via computer to
Cassini's natural color imaging.
So I would not dare at present to adapt the
outer haze
colors to the (rather uncertain) colors of Titans
surface, as you apparently did above.
2) To me it is entirely plausible that the surface colors appear
more reddish-orange as compared to the brighter
yellow-orange shade of Titan's outer cloud hull! The
respective physics is well understood but complex in detail
and can be carefully analyzed. Before that is done, it might
at best be justified to infer preliminary and qualitative
color-adaption of Celestia's /surface/ texture from the surface
color photo, as you did above and I tried in "users->t00fri's
Titan@Celestia". Also, as you did as well above, the /lower/
atmosphere colors in solarsys.ssc should me matched.
An interesting exercise might be to determine the position of
the sun at the Huygens landing site from Celestia, when the
color image was taken. Then we can apply some simple
physics arguments already about a possibly more red
illumination on the surface!
You surely remember that the physics of sky colors depends
nontrivially on the size of the haze droplets, their desity, the
altitude of the atmosphere and last not least on the position
of the sun...With Grant and Spiff we had some extensive
discussions about these important effects some time ago.
Bye Fridger
