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I'd like to know if anyone has any ideas as to how to do the following:

I want to create planetary textures for Celestia
(see http://www.shatters.net/celestia/)
but creating a rectangular image for the texture
and then having this projected onto a sphere
makes the process tedious trial and error --
the poles are really hard to get right.

I'd like to use some sort of modelling software
to 'draw' the texture on a spherical body
and then unwrap this into a rectangular image file
suitable for importing into Celestia as a planetary texture.

Any (useful) suggestions would be appreciated!

Thanks

Uniquely texturing entire terrains sounds pretty cool, but the concept isn't entirely new - just an evolution on an already-existing idea.

I think the Myth RTS games from Bungie used very large textures for the terrain, and this moved on to Halo - terrain there is drawn using a large, low-resolution texture - the red, green and blue channels are used for the colour, while the alpha channel is used to determine which of two detail textures should be used - e.g. grass or sand. It works quite well. I think Far Cry does something similar, but more advanced still.

The former are still low-resolution, though - but the not-a-game Celestia has 'virtual texture' support, for rendering silly levels of detail on planet surfaces. Like, up to 128k by 64k pixels. The textures are split into many, many files for each level of detail, which are streamed in from the hard disk when required. Works fairly well.

Combining the two approaches, though, seems very new - the 'Mega Texturing' from John Carmack is probably dramatically different from an implementation point of view, and sounds rather interesting at any rate - the description of the upgraded, non-Quake-Wars version makes it sound like it could uniquely texture a whole world beyond just terrain, so could work for simulating real cities, as opposed to smoke-and-mirrors game cities.

I'm sure he talked about this in a .plan thing some years ago - anyone want to find it?

The article discusses NASA WorldWind but several interesting links are missing. Amongst them: Punt, a WW fork. Heck, you can also see Microsoft Virtual Earth data in NASA WorldWind itself. Even Mars 3D in WW. (I stop here, if this interests you, read slashgeo.org ;-))

I don't know if Stellarium counts as "software for space exploration", but it's worthed. Celestia too.

While it may seem really fast, when broken down into comprehendable units, light is not really that fast

Check out celestia if you're interested in exploring the universe in the way that relativity won't allow.

http://www.shatters.net/celestia/

Its lots of fun!

A great 3D map of the universe is Celestia. Its set up similar to Google Earth in that you can fly around and search for different celestial objects. Its pretty cool.

Hey this is kind of offtopic, but if you like Xplns you should check out Celestia!

Like this hasn't happened before. Ever.

If the dot com bubble taught us anything, it's that "If it's free on the internet, it's unreliable and fully controlled by somebody who will run it into the ground".

I would hope not. Otherwise the GIMP, that universe-in-a-box Celestia (which I do admit was held back a bit when main man Chris Laurel took a long break; it has a lot less bugs on Windows now that he's back) and newly-ad-and-cost-free Opera wouldn't be on my PC anymore.

All quite reliable to me (on Windows, mind you, so something was done right)--oh, and GMail. Amazing. Don't like text ads? Get a bigger screen. ;)

The key is looking at sites, blogs, forum comments, and the like, and reading what works for some and what just sucks. Good friends help, too.

The Great Stellarium (open source):
http://www.stellarium.org/
Celestia (also free):
http://www.shatters.net/celestia/
NASA's astronoly picture of the day:
http://antwrp.gsfc.nasa.gov/apod/

Stellarium is really a must-download for anyone even slightly interested in astronomy. It's another open source software success.

There is always the moon from our overlords... but moon through NASA's WorldWind too.

Another interesting program is Celestia. I haven't tried any, but there are apparently lots of available high-resolution images available for various parts of the Earth as well as higher-resolution images for some of the other planets. The controls for moving around aren't intuitive, but it is a lot of fun to go zooming around the galaxy (and even some nearby galaxies, rendered as grayish-looking 3-d blobs).

...it'll inspire Chris Laurel to work on it again. Fellow makers Dr. Fridger Schrempp and "Toti" have been left largely on their own with the code these days, it seems. It's amazing in any case, and I doubt it'll need any work from Chris for me (or anyone else) to have the new (if at all different) Blue Marble on Celestia.

The best way to enjoy NASA's blue marble is through Celestia.

Yeah, because nobody has ever thought of doing that before.

But yeah, on the wider Windows stuff, it comes from the wider open source community, and isn't Linux only (eg. things like Inkscape, Ethereal, Orbiter, Celestia, Blender, ...). They're all stand-outs, and they'll all either still be here with us in 20 years, or some better open-source software will have surpassed them.

"Unlike Voyager or Hubble, Cassini is in a unique position to study ring spoke phenomena at Saturn."

With Celestia, you can actually follow Cassini's path as it follows Saturn. It really puts the above statement in perspective (plus it makes u feel like an astronaut).

I changed my pants, but I'd do it all over again if I could figure out a way to easily export the data into formats that other programs understand (eg. Celestia, or even just Blender).

I think this is what you're talking about: http://www.shatters.net/celestia/

my brother showed it to me a while back. It's a real time planet simulator. It can be sped up, slowed down, all that fun stuff.

For extra fun: Open up Celestia (come on, you all should have a copy), and turn on consteallation drawing and labels. Admire all the signs of the Zodiac. Pick a star at random, select it, and hit "g" for "Go to". Now admire what all the signs of the Zodiac look like from a slightly different point in the Galaxy. For extra points, pick something nearby like Alpha Centauri to travel to.

Yes I'm sure those randomly scattered arbitrary selections of stars spread over vast galactic distances are meaningful. I'm sure that the fact that they all become skewed haphazard messes of huge long lines from any viewpoint other than the Earth is justone of those things.

Jedidiah.

Your text gives the idea that Celestia is an amateur software. Let's just make it clear for those who know nothing about it. Celestia is an excelent software, just isn't designed for this purpose.

If you are just starting, it might also help if somebody told you where to look:
I'm new to stargazing but I downloaded Celestia (free) and flew over to the upper hemisphere of earth and set the date to tonight (June 25). You can find the planets by watching where the sun sets. The planets will set at that same spot about 2 hours later. They will be moving down and to the right at almost exactly a 45 degree angle to the horizon. So that means that after sundown, you can look up and left of that spot to find the planets. Look relatively low in the sky.

Not specifically for this event, but a really awesome simulator for astronomy stuff in general is celestia. http://www.shatters.net/celestia/

Click on the earth, hit g (actually celestia starts you at earth), you can hit o to mark orbits to make it easier to find the planets (hit p to show labels to identify the planets themselves.)
I hit shift-g to go to the surface of earth and then find the planets. Can give you a good idea where to look really. Being on the surface isn't particularly important at first, don't want the planet being between you and your destination until you are sure it wouldn't be.

It doesn't always much like things really do, especially with atmospheric simulation not being particularly complex in celestia, but it is cool none the less. Particularly to click on one of the three planets close together, hit g, then look at everything from their perspective.

For people really wanting to see how it would look to travel at the speed of light, you could always try the open source 3d space simulator Celestia.

I find that watching planets whiz by as you travel at the speed of light is pretty entertaining. I've had some fun just trying to steer with a joystick at this speed.

Of course, I suppose if you really were going this speed (or even 99.9% of it), you'd see some wierd spectral shifting (or that circular blur effect as in the article's animation), which is not shown by celestia.

This sounds perfect for one of my favorite 3D programs, Celestia. My current textures directory is 8.7g. I'm sure I could use that extra RAM for the 6.5g of that that makes up Earth.

KStars is a pretty decent program, though I've found that Celestia is a bit better all around, it's demo mode is really neat, a reminds me a bit of the space part of he powers of 10 video. The nice thing about Celestia is that your not bound to earth, and can fly around the universe.

What educational software packages are available for Linux?

I'm not sure what you're looking for exactly, but off the top of my head (and a little freshmeat help):

Primary school level: Gcompris is great, has a large bundle of games targetting everything from spelling to geography to math, and is easily extensible.

Astronomy: Both Celestia and Stellarium provide great tools for teaching kids of all levels about our universe.

Mathematics: You can use basic spreadsheets if you like, but there's also Octave for vector and matrix mathematics and Maxima (and several others that I can't recall right now) for symbolic algebra.

Chemistry: There's stuff like Ghemical and Gperiodic which aren't half bad for exploring various chemistry concepts. Then there's stuff like GenChemLab which is pretty neat.

Physics: There's physics simulation software like Physics3D , and there are others around if you care to look.

Computing: Well, you've got all the programming tools you want, but also things like DrPython to make it easier/fun for students (even at lower school levels).

General knowledge: Wikipedia is accessible from anywhere.

Okay, there's a science bias there, but it's not a bad start for what I can think of, or find in 2 minutes of freshmeat.

Jedidiah.

How about Tycho? Just think of the view with an 85,000 meter mirror.

Part of the idea with a polar crater is to protect the instrument from temperature variations, something you would get a lot of on a monthly basis with a mirror anywhere else on the Moon. Tycho sits in sunlight for two weeks, then in darkness for two weeks. That's not a stable environment.

Also, a telescope made with a liquid mirror can be aimed in one direction only, towards zenith. Even the slow, monthly rotation of the Moon wouldn't allow for significant exposure times without motion blur, something you don't want when photographing distant galaxies spanning less than an arc second in the sky. The celestial poles are the only two spots in the sky that don't move around (they merely rotate), allowing for arbitrarily long exposures (the article suggests a year) using a camera synchronized with the sky.

If Celestia has the correct orientation of the Moon, the lunar axis points at constellation Draco in the northern hemisphere and at constellation Dorado in the south, the latter including the Large Magellanic Cloud. However, I don't know what particular deep sky objects would be visible using a telescope such as the proposed one at either pole.

Dione will get a very close pass, in october next year, don't know if that feature will be in range though.

Appearantly not, if I'm to believe the trajectory data for Cassini distributed with Celestia. That data is certainly not reliable, as Celestia predicts Cassini will collide with Dione on October 11, 2005! However, if we assume the prediction is mostly correct with respect to when Cassini will be nearest Dione, the linear canyon (which seems to be located at 10N 40E according to the maps produced from Voyager photos) will unfortunately be on the dark side at that time. When the sun rises some six hours later, Cassini will also be above the horizon, but 200,000 km away.

The December 14 Dione flyby isn't listed among the encounters in that tour schedule, probably because 80,000 km isn't considered "close" enough. Maybe there will be yet another photo opportunity, but I doubt it. Another possibility would be for NASA to adjust the arrival time for the October 2005 encounter in case they want to get better shots of the "wispy" area, but that seems just as unlikely to me.

The 'text' part of reading should stay in 2D land, but think about the visual feedback of flipping a page, or seeing how thick the side of the book is.

What book? There is no book! There is no page, either!

See, that's the thing -- usually when somebody comes up with a 3D interface, they try to make it similar to some real-world object (e.g. books or rooms or radios). But the real question is, is that metaphor useful? Why should the text I'm reading be presented as if it's a book? In a computer, what do pages mean?

The real innovation in computer interfaces will come when we realize we aren't trying to interact with things, we're trying to interact with information. Books are not information; they're just containers for it -- and suboptimal ones at that. Why would you want to interact with a virtual book when there's an infinite number of other ways that are likely to be better?

Take the example of a web "page." It's not (usually) just a page, it's a complete group of thoughts. I don't need to see how "thick" it is to know how long it is; the metaphor of the shrinking scrollbar is more useful. Also, with a normal book you can only go forwards or backwards; with hypertext you can go in any direction. As far as a really good interface for information goes, look at the "Chaos" feature of Everything2. See how it uses the idea of "near" to group nodes of information? Now, imagine that each node is a star, and the group of nodes as a constellation in the galaxy of human knowledge. Now, imagine using an interface that works sort of like Celestia to navigate that galaxy. Doesn't that sound like a better metaphor than a book?

A book is linear, but information (which is what a book is designed to convey, right?) is a graph. Wouldn't a representation using a graph be better than a linear one?

try http://www.shatters.net/celestia/, you won't get a gigapixel (unless you do a bunch of screenshots, and stich them), but you can zoom as far as you want (and load some nearly gigapixel sized textures).

Then you too go to Phobos and marvel how loomingly big Mars is above you. Or bekow you, depending on how you feel.

A truly awesome Universe simulator.

If all else fails, you can simulate it on your own PC.

It looks lovely and smooth (and orange) in Celestia.

So how come NASA is surprised when Titan turns out to look similar to existing models? Do the rest of us know something that NASA doesn't?

It's funny. Laugh.

Hope someone would integrate this in to Celestia or the other way around. Explore the deepest corners of the galaxy and be in your neighbourhood in a splitsecond.. Nice..

For those of you who like this sort of software, check out Celestia. It is a 3D space simulator, and lets you visit objects in our solar system and a bunch of stars. It's really amazing, and it's open source! My sister uses it for teaching astronomy to the neighborhood kids in their home-schooling class.

I've noticed that these two stars are conspicuously absent from Celestia. Conspicuous because B is the closest white dwarf star IIRC - it should definitely be included. So much for learning what the sky looks like from Vulcan!

By the way, the XPlanet project (xplanet.sf.net) can use images like this for the night-side rendering of a near-realtime Earth on your desktop.

Another great program for rendering images of the earth, the solar sytem, and parts of our galaxy is Celestia. It's GPL'd, and runs under most of your favorite platforms. Very addictive.

I have, on my wall, an earlier version, from when I was a kid. Comparing the two is actually sort of scary. On the other hand, it's time to update my earth at night graphics in Celestia

Probably suggested already, but Celestia will provide glorious renderings of the Earth, complete with some ridiculously high-resolution texture maps.

There are 'night maps' based on the Earthlights image - they're probably a bit bright when seen in Celestia, especially when compared with the day side of the Earth, but they look utterly lovely. :-)

Once you've built your perfect Earth, you can work on kitting out the rest of your ideal Solar System with the other stuff people have posted on the Celestia Motherlode...

Celestia rocks. It's a free (GPL program/public domain data) program where you fly arond space and see stars and planets and stuff. Educational, fun, and free!

Celestia, for those who do not know, is an OSS planetarium program for several platforms available here. Its a relatively small download (11mb), and is lots of fun.

It was especially useful for me during the recent lunar eclipse.

If you want to get a good perspective on it all then there really is only one way: Celestia!
Then download the model and the trajectory information of the cassini probe from some able contributors!

*laugh* The star name + letter combination will have to do for the meantime. The roman numeral convention assumes that we know all the planets in a star system, so Earth being Sol III and Mars being Sol IV is just grand for us.

For jolly gas giants around far stars, though, we don't know whether there are any other planets in orbit, or at the very least, we don't know how many other planets there are. Someone observing our system with the equivalent of our current technology wouldn't even be able to discern Jupiter or Saturn.

When we somehow (and I'd love to see how!) manage to figure out an entire remote planetary system, perhaps we'll switch back to roman numerals :)

Celestia keeps relatively up to date with discovered extrasolar planets, and it uses the star + letter convention. Obviously, though, the planet texture used when you go visit the planet is merely a guess :)

The best, and I'd say nigh-only way to teach an astronomy class is with the aid of a telescope and programs like Celestia. Its fine to go on about the moons of Jupiter and the distances involved, but quite another thing entirely to actually pull out a telescope and look, or zoom around in Celestia and explore for yourself. Yes, there are other things that have to be taught, but without that basis, it seems like teaching physics or chemistry without labs.

I do speak partially from experience, as I've had a number of astronomy teachers over the years who have bothered to actually pull out telescopes. Most these days can't be bothered, as it requires extra effort to organize an after-hours field trip. But it still helps a lot.

Current ISS position, updated every minute.

Yesterday in the office: I had my iBook beside me, running Celestia. Try this: Current time, realtime, Select ISS, Go to ISS, Sync Orbit. Maneuver a bit around the station till you're where the Destiny module window is, then adjust the viewpoint so you get a nice horizon view. (Or just Track Sol.) Then just leave it running. Voila: anytime you feel like seeing what the ISS crew can see from Destiny, just look at Celestia. :)

(Interestingly enough, comparing the Celestia ISS view with the Station Location website, I found that Celestia's synchronization is a teeny bit off, but not by much. Nice work!)

I'm afraid I couldn't find the path files (3ds model is available though) for this body. However, Celestia 1.3.2 is currently in beta testing, and it now has support for JPL's "Ephemeris" orbital data that might be usable instead of Celestia's .xyz trajectories. There seem to be some interesting stuff in a Google search. Maybe you can download 1.3.2 (I could only find a Windows binary) and read up / ask at the Celestia forums for more help about where to get Ephemeris data, and how to use it.

Where can I get a Celestia add-on for this asteroid?

This could be useful as texture map addons to Celestia, along with textures from Planet Portal, etc...

Also, don't miss this site for your amateur astronomy needs. :-)

I made a quick video using Celestia of the Venus transit. It requires Divx and it's about 330KB in size and runs for 18 seconds.

Here is the link. Ugh, be gentle. :)

This also just gave me an idea. Being in North America, I might use Celestia to watch this happen in real time on June 8!