1.3.0 Prerelease

[imh]

I have already split my SoslarSys file up into smaller chunks.
all i have left in my solarsys file is all the Planets, Deep space spacecraft, and the main asteroids. (Ida, Dactyl, Eros.... ect ect.)

I'm impressed! I've only been using Celestia for 4 days and already I've got two Ceres floating about...

[Darkmiss]

Welcome to the Celestia Forums imh.

how did you manage that ?

[alexis]

At lightspeed you would "see" all the stars condensed into an infinitely blueshifted dimensionless point dead ahead.

Actually, all light from stars would be infinitely redshifted in the light-speed limit! This is due to the relativistic Doppler-shift that includes time-dilation. See the entry What would a relativistic interstellar traveller see? I wrote for the Usenet Physics FAQ.

/Alexis

[Calculus]

At lightspeed you would "see" all the stars condensed into an infinitely blueshifted dimensionless point dead ahead.

Actually, all light from stars would be infinitely redshifted in the light-speed limit! This is due to the relativistic Doppler-shift that includes time-dilation. See the entry What would a relativistic interstellar traveller see? I wrote for the Usenet Physics FAQ.

/Alexis

This is a very interesting explanation. Thanks for posting the link.

[Redfish]

So your explanation tells me that by looking forward i could see my own ass while flying at near lightspeed?

And what about real warp, so speeds above 1 c, would that make you see nothing at all, cuz every light is shifted towards invisible spectral areas?

[selden]

Redfish,

There is no such thing as "real warp," so any description of the visual effects would be strictly make-believe. In our universe there is no way to travel faster than the speed of light in a vacuum.

(added later)
Things *can* travel faster than the speed that light travels in a particular medium (like in water or a rarefied gas), which causes strange effects. Those effects are similar to the sonic effects of travelling faster than the speed of sound, although they're electromagnetic effects rather than pressure wave effects: shock waves, for example (Cherenkov radiation).

[chris]

OK I am off the board for a few months and already there’s a new version!?


Also chris to do you plan to clean up the directory for the 1.3 release?
(reference) http://www.celestiaproject.net/forum/viewtopic.php?t=1076

Yes! This is what I'm currently working on . . . I've modified the extras directories scan so that it's recursive. Now I'm working on making it possible to have textures, models, and xyz files in the same directory as an .ssc file.

Finally you one said that the biggest problem with the directory cleanup is with the images, and what to do about texture resolutions. I think the simplest solution is to make the resolution user definable by adding an attribute to the texture command.

So now

Texture "earth.jpg"

Would be written like

Texture(1) “earth2k.jpg”
Texture(2) “earth4k.jpg”
Texture(3) “earth8k.jpg”
Texture(4) “earth16k.jpg”
Etc…

Where the number (#) refers to an increase in the resolution of the image. This would replace the need for the current separate directory for different resolutions. And as an added benefited you now have more resolutions to play with (0-9)

I think that I'm going to stick with the current scheme, except that a textures directory will be allowed it the same level as an .ssc file.

--Chris

[alexis]

So your explanation tells me that by looking forward i could see my own ass while flying at near lightspeed?

No... not unless you separated from your ass at near lightspeed. It's the relative speed that matters, you know. Relativity theory

(sorry for this off-topic post)

/Alexis

[granthutchison]

Actually, all light from stars would be infinitely redshifted in the light-speed limit!

I think you might be wrong, there. Time dilation of course has an effect, but it is eventually overpowered by first-order Doppler effects. So as your spacecraft approaches light-speed, although the proportion of the sky that is red-shifted tends asymptotically towards 100%, the number of stars it contains goes asymptotically to zero - all the stars in the sky are eventually wrenched around by aberration and incorporated into the tiny blue-shifted spot ahead of you.
There's a simple relationship between the angular radius of the blue-shifted patch you see ahead in the moving reference frame, and the radius of the patch of sky it represents, as it would be seen by an observer at rest at your location:

blue-shifted radius (moving) = 180 degrees - blue-shifted radius (rest)

So as velocity increases, the moving-frame and rest-frame radii go like this:

Code: Select all

velocity                     blue-shifted               blue-shifted
                                  radius                       radius
(v/c)                         (moving)             (equiv. in rest frame)
0.9                           51.2 deg                     128.8 deg
0.99                          29.8 deg                     150.2 deg
0.999                         17.0 deg                     163.0 deg
0.9999                         9.6 deg                     170.4 deg
0.99999                        5.4 deg                     174.6 deg
0.999999                       3.0 deg                     177.0 deg


and so on. That blue spot, although it's shrinking, is gobbling more and more of the sky.

Grant

PS: Sorry, the originally posted table was unreadable - I've converted it to "code" to get the columns to behave!

[alexis]

Alexis> Actually, all light from stars would be infinitely redshifted in the light-speed limit!
Grant> I think you might be wrong, there.

You're right, I misplaced a gamma Thanks for correcting me.

/Alexis

[imh]

I'm impressed! I've only been using Celestia for 4 days and already I've got two Ceres floating about...

Welcome to the Celestia Forums imh.

how did you manage that ?

Well, there's a Ceres in the main solarsytem file and then i downloaded the asteroids_IMPS file which also has a Ceres. I guess Celestia isn't written to detect repeated names within a solar system.

iain

[John Van Vliet]

I will let you knoe how it is on a nVida gforce2 mx/mx 400 with the 41.09 driver

[Redfish]

There's really one feature i'd really like to see soon. I think it's not very difficult to implement.

Instead of the standard 5 seconds travel time when pressed G to goto an object maybe a new shortcut combination like Shift-G or CTRL-G could be added, and asks the user to enter the total travel time.

At the moment i think when travelling great distances, you're missing a lot, for instance flying from out of the galaxy to the sun. I'd like to do this in maybe on minute instead of the standard 5 seconds, which is over very fast.

you can now center to an object and start flying, but at higher speeds it's hard to 'brake' early enough.

Any ideas?

[Jango Fett]

Shouldn't nebulas stop dissapearing after 1 ly in version 1.3pre? Because it dissapears to me...

[Redfish]

No dude, cuz in reality they dissapear as well when you're farther than 1 ly away :P

No of course they shoudn't, but it's a know problem.

[Guest]

Is it possible in multiview to have the planets in their real size? For example, be able to have Jupiter and a small Earth in comparison side by side representing their real sizes. If this is not possible, I guess this is a request for a new feature.

I haven’t read all post, so I’m sorry if this has been asked before.

[chris]

Shouldn't nebulas stop dissapearing after 1 ly in version 1.3pre? Because it dissapears to me...

You have to download the new version of Rassilon's nebula. The old version of the nebula will still disappear because it's just an immense planet, and Celestia is not designed to allow planets on the order of one light year in size. Celestia assumes that no planets are visible from a distance of a light year, culling them without checking their sizes.

--Chris

[Rassilon]

Get it here:
http://24.144.43.100/index.php?op=downloads;catd=6;ss=0

[Calculus]

Is it possible in multiview to have the planets in their real size? For example, be able to have Jupiter and a small Earth in comparison side by side representing their real sizes. If this is not possible, I guess this is a request for a new feature.

I haven’t read all post, so I’m sorry if this has been asked before.

Yes you can do it, I have a snapshot of 8 planets as seen from earth in my gallery, made with the multiview option. But I chose to show them approximately at the same size to fill the image. It is an easy task to show their real size.

[ANDREA]

Is it possible in multiview to have the planets in their real size? For example, be able to have Jupiter and a small Earth in comparison side by side representing their real sizes. If this is not possible, I guess this is a request for a new feature.
I haven’t read all post, so I’m sorry if this has been asked before.

Yes, you can. If you go at my page

http://www.ara-frasso-sabino.org/andrea_celestia.htm

You'll find an example and the instructions to obtain it.
Hope this will help
By
Andrea