fulldome projection

[trenner]

I would just like to put in another plug of appreciation for Celestia. I have been experimenting with fulldome projection for about a year now, and of course half the job is having something to project. All the other software and hardware out there is REALLY expensive, and of course Celestia is free... the cost depending on how much is invested in the hardware.
If you can't afford a fisheye lens projector, or multiple digital projectors ( Like me ) you can simply reflect the projection ( off slide projector, film projector, digital projector) off a hemispherical mirror
The ISS is 8 feet across when it comes up! Stellarium is a good program, but Celestia's graphics and Nebulas just blows everything else off the map.

Regards
Terry Renner

[Evil Dr Ganymede]

What, you're actually managing to use Celestia in a dome? Like a planetarium? I thought you needed one of those Zeiss Projector things for that...

(and er, waves up-island at Terry )

[trenner]

Hello, fellow VIer!
For a neat ( but expensive) projector, you could have a look at this-
http://www.digitaliseducation.com/

And to get an idea of fulldome, there is this-
http://www.fulldome.org/index.php?optio ... &Itemid=28

And to use a mirror, like I am, there is this-
http://astronomy.swin.edu.au/~pbourke/p ... omemirror/

Stellarium looks pretty good reflecting off the mirror- I especially like this program, as there are constellation figures on it... any chance we could
"borrow" those for Celestia?....

Regards
Terry Renner

[selden]

If constellation images can be provided as a series of vectors, it wouldn't be very hard to translate them into a CMOD line model.

Alternatively, an all-sky picture can be projected onto the inside of a sphere in Celestia, but it wouldn't be as sharp.

Of course, whatever images are used would have to be publicly redistributable and their provenance documented.

[BlindedByTheLight]

Trenner - VERY cool! Any chance you could upload some close-up pictures of your mirror/set-up? It's kinda hard to see so far back in the low light. But, either way, like I said - VERY cool!

[BlindedByTheLight]

Dude! You're a Burner? I was just checking out your site and saw the photo in Black Rock City! How long was the Pandome up? I never saw it - though really, not too surprising considering how dang big that place...

Steve "Black Light Furry Car" Binder

[maxim]

If constellation images can be provided as a series of vectors, it wouldn't be very hard to translate them into a CMOD line model.

Alternatively, an all-sky picture can be projected onto the inside of a sphere in Celestia, but it wouldn't be as sharp.

What about distinct billboard projection for every constellation image?
...and, without further inspection of the code, what about the following:
Constellations are built by drawing lines according to a list of stars. There is a huge amount of stars in celestias database. Very detailed pictures could be drawn, if every constellation would consist of hundreds of vectorlines. Or is there any constraint about stars that could be used for constellation definition?

maxim

[selden]

Yup, billboards could be used for the individual constallations, too. It's just that there would be so many of them.

Lines can be drawn between any two stars in Celestia's database. However, I suspect that the results might be rather crude compared to the elaborate images often used. (I'm thinking of the Uranometria images as an example. See http://virtualsky.org/uranometria/index.html for some of them.) Also, finding the stars closest to desired picture's lines would be somewhat challanging, although probably not impossible.

Terry,

I've been assuming that you're interested in images similar to the Uranometria ones. I'm not familiar with what's in Stellarium.

[edit]
I just googled for Stellarium.

Terry, have you considered contacting Johan Meuris directly? He might be willing to have his pictures translated into an Addon format that Celestia can use, or maybe even doing it himself.
[/edit]

You are aware that Celestia already can draw stick figures for the constellations, right?

[trenner]

Whow..... starting to get a bit of an anxiety attack......

Yo Steve
I'm more of a wannabe Burning Man festival dreamer. I'm dying to know how they project in their domes.
http://www.burningman.com/

.... There seems to be no end to what Celestia can do. Draw the constellation figures??

I've been more taking a lead from Paul Bourke. He guided me to Stellarium. I was assuming it was Paul that modified Stellarium for fisheye projection. I'll make enquiries
http://astronomy.swin.edu.au/~pbourke/projection/

How do you put pictures in this forum anyways?? The projection setup is pretty basic anyways. Any kind of projection reflected off a hemispherical mirror will maintain focus.... as long as your reflecting onto the inside of a dome. It HAS to be high resolution, or it's like looking through a screen door.
The alternative is fisheye projection, or setting up about six digital projectors around the perimeter. Got money??

Regards
Terry

[BlindedByTheLight]

Hey Terry...

Oops - my bad, I thought that link was yours. But I would definitely be curious to see pics of your set-up as well. Not sure how to put up pictures. I'm going to take a guess that it works like quoting... you host the picture somewhere than link to it using the "Img" tag (click on "Img" above, which puts a start code in the field - then paste in the link to the image - then click "Img" again which puts the "end image" code). In fact, I'm going to try it here, if you see a picture, that means it works:




http://www.backtoone.com/BurnMan/index.html

A Celestia Burningman art project would be amazing. If you haven't been, you have to go - despite its reputation, the event is really about the art, and the art is literally out of this world.

Cheers,
Steve

[selden]

.... There seems to be no end to what Celestia can do. Draw the constellation figures??

Select "Constellations" in the menu Render / View Options.

It sounds like you might want to spend some time reading Frank Gregorio's User's Guide for Celestia. It's available at http://celestiamotherlode.net/catalog/d ... ation.html

[trenner]

OK
Centered on Polaris
Saved to file as a jpeg
Drew a picture of a bear cub over Ursa Minor outline ( which will prove again that I can't draw)

Now, is there anything I can do with this?[/img]

[selden]

Your picture isn't showing up, if that's what you intended.

You might want to take a look at http://www.lepp.cornell.edu/~seb/celest ... board.html
It explains how to display pictures within Celestia.

[trenner]

..... now I'm reaching for the Tylenol again. I have been unable to learn anything about building, using (or hosting) web pages. Is there anywhere I can email this jpeg to ?

[trenner]

Man, I'm getting dense. I just emailed you Seldon

[BlindedByTheLight]

Hey Selden... maybe this is not the place to ask - but since you brought up billboards, a quick question. You wrote:

In order to use this 3DS model for different objects in Celestia, ones not called "Billboard", you have to copy the model file, creating a new .3ds file in a models directory. Each copy of the model must be given a different name.

Got that. But...

You also have to edit the new 3DS file to change the name of the texture image file that it looks for. Currently it specifies billboard.png. You cannot use most text editors to make this change because of the binary codes in the model file. A binary editor like HexEdit can be used, but I found that Emacs works quite well."

Is there any technical reason I couldn't just rename the .3ds file but still keep the texture it looks for "billboard.png"? And then I just have five different textures, but all with the same name ("billboard"), in different corresponding nebula directories?

In other words...

So Nebula1.3ds (in its own Nebula1 directory) will look for billboard.png IN THAT directory. And Nebula2.3ds (in ITS own Nebula 2 directly) will look for a file CALLED billboard.png (but with a different picture) in that specific directory. And so on.

Or does Celestia demand every single texture have its own unique name?

Thanks as always,
Steve

[selden]

Steve,

I suspect your idea would work, although it might lead to some confusion. When I wrote that document, I was thinking about the situation when several billboards were being developed in the same set of directories, not as separate Addons in separate directory trees.