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Real Jupiter vs Celestial Jupiter

Posted: 16.07.2003, 14:44
by flym
Look at the following picture.
It's a comparison between real image of Jupiter taken by the Globas Mars Surveyor, and a Celestia image from the same perspective.
Take into account that the MGS image was corrected to enhance the moons light. Then it is evident that Celestia's Jupiter looks very realistics 8O while the Celestia's giovian moons (like planets seen from far away) look too brilliant :? .

Image

Posted: 19.07.2003, 03:34
by Borg Collective
You wanted to say that moons are "too bright"... Didn't you :-D?

Posted: 19.07.2003, 12:15
by HankR
Yes, that's what he said.

- Hank

P.S. This issue has been discussed here many times. The Sun doesn't seem as bright in Celestia as it does when I look at it in the sky, either. (Just kidding -- DON'T try to verify this by looking directly at the Sun!) The discrepancy is due to the fact that your computer display cannot reproduce the range of brightness visible in reality.

Posted: 19.07.2003, 13:55
by granthutchison
Yes, As Hank says, I think what's going on here is that Celestia's Jupiter is too dim. The real image of Jupiter and the Galileans required two separate exposures because a single image with the Galileans at correct brightness would have "burned in" Jupiter, obscuring all detail. Your monitor physically can't render Jupiter bright enough - so the Galileans appear too bright in comparison.

Grant

Posted: 19.07.2003, 22:22
by julesstoop
On my system:

Go to Mars now and look at Earth; zoom in => Moon appears as bright or even brighter than earth until you have enough of a magnification to see the textures. This is a seriuos flaw imo (unless my system and not the code is the cause).

Posted: 19.07.2003, 23:13
by bh
IMO...you are being way too fussy!

Celestia is a real time space sim...Of course you can recreate real still photos from NASA or whatever...thats the greatness of this app surely?

FOV and other factors will make it as accurate as you want...if you know how!

Regards...bh.

Posted: 20.07.2003, 12:09
by fred
Do you know how bh? Can you tell us?

Posted: 20.07.2003, 22:12
by bh
Sorry Fred...I can't remember what my point was. I must refrain from ESB and posting!

Regards...bh.

Posted: 20.07.2003, 22:40
by granthutchison
julesstoop wrote:Moon appears as bright or even brighter than earth until you have enough of a magnification to see the textures.
Hmmm. I see what you mean. Earth is a bigger blob, but because it's slightly coloured by the Color statement in solarsys.ssc, it doesn't look brighter than the Moon. I'm pretty sure that's what's happening - I just toned down the Moon a tad by pasting the Earth's Color statement

Code: Select all

Color [0.85 0.85 1.0]
into its definition, and now it looks noticeably dimmer than the Earth.

Grant

Posted: 21.07.2003, 18:23
by julesstoop
Nice. Clean and simple solution, thanks!

Posted: 21.07.2003, 18:38
by granthutchison
Oops. Didn't mean to propose it as a solution - more as an observation on the nature of the problem.
How about

Code: Select all

Color [ 0.9 0.9 0.9 ]
for the Moon instead? Then it'll look greyish rather than blueish ...

Grant

Posted: 22.07.2003, 23:13
by julesstoop
Well, I like these quick and simple fixes (and have been experimenting with the color values myself hinted by your suggestion), but you are right it's not a real solution for the problem.

I guess the problem should be fixed by the albedo parameter, but it doesn't seem to influence the brightness of unrendered planets and moons.