Celestia Forums

Check out this flash signature I did back in 2005, maybe it will give you some ideas :D The "galaxy" is generated, but you can do the same with bitmap texture very easy. Edit: in case it is not obvious how that works, I thought I'd add few words about it. The galaxy "image" is sliced into ~100 image...

the thing is that flux I was calculating is luminous not radiometric, that is, not just surface x integral of spectrum, but integral of spectrum multiplied by CIE 1931 y color matching function. I believe this causes residual scattering. however, "degree of linearity" is just enough for my purposes.

I couldn't even convert to solutions perhaps, if you solve above problem, you could donate new solution/project files to the team so we all would use it?

I have fixed my code so now results are totally as expected



Thank you again.

never mind, people pointed out that I missed dependance on radius.

okay thanks that see to make sense.

p.s. I changed my plot a bit, so now it looks more like right.

I posted it under celestia development forums but I wonder if, per chance, it is my misconception, so I ask it here.

Is that true that absolute magnitude should be proportional to star temperature; that is, are hotter stars always brighter?

I thought the fault is on my side so I plotted M against temperature T.

Aside from wonderful stars with millions of kelvins, again, no correspondence:

It is my understanding that absolute magnitude M and (total) flux F emitted by the star are related as M = -2.5 log F + const. That is, if you take temperature T, calculate and integrate black body spectrum across visible wavelengthes, and plot resulting values against M, you should see some sort no...

I've just made another map, with number of stars mapped in blue, temperature in green and sqrt(radius) in red (this time not entirely accurate, because GIF only allows 256 combinations of colors):

Did you ever wondered how many stars are there in some specific direction? Well, I did. In the image below, this number is color-coded per "square" degree (image is 360x180 RA/dec map): http://img58.imageshack.us/img58/6229/statisticscelestia2gy.gif You can clearly see two sines. If one is Milky Way...

It comes from buildstardb.cpp, function HipparcosStar TheSun(), where parallax is set to 1000000.0f; this causes sun to be listed with distance 0.00326167 ly in data/stars.txt and data/nearstars.stc :O Compare that to astro::AUtoLightYears(1), which gives 1.580302e-5.

I wonder if it is even used...

i have recently been fighting to compile subset of celestia files i wanned to play with on visual studio 2003 (the one that intoduced solutions). ususally it imports older dsw/dsp just fine, but this time it could not import any of celestia project files (said they are "broken"). this is something f...

Isn't it possible to actually put observer in the spaceship, so he would see things through some kind of window, and then actually move observer out of the ship?

Now when I tracked it down to Renderer::renderBodyAsParticle() I see this is a bit more complicated than just a color thing, right I will experiment a bit and get back with something, if anything, tomorrow......

oops I edited my post without realizing that it has been answered (see above)

abusing edit button again: I do realize that full-blown XYZ support might be an overhead, but I think at least some sort of pre-computed RGB->RGB correction based on Y value would be worth of having.

searching on my own I came down to celestia-1.4.1\src\celengine\starcolors.cpp where it jumps to http://www.vendian.org/mncharity/dir3/blackbody/ where, in its turn, following is said: These values show color chromaticity (hue and saturation), but ignore brightness. what code handles that, or does c...

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