Celestia: Open Source Application of the Week - Week of 2017-09-25

Submitted by sudo moderator in freeAsInFreedom

Last week's thread (non-onion link).

This week's Open Source Application of the Week is Celestia, a 3D space simulator. Basically, this program lets you look at pretty things in space, and I love it.

First of all, let me say this program looks gorgeous. Just look at some of these screenshots. The textures look beautiful (unless you zoom in really close), as do the atmospheric optics, and they even modeled the planets as oblate spheroids, so Jupiter appears to be slightly squashed, like in real life. You can spend hours and hours playing around with this program.

Not only does it look good, but it's also very accurate. The orbits of the planets are modeled very accurately, so you can fast-forward in time by hundreds of years, and see where the planets will be then. But Celestia doesn't just model the solar system; it also plots thousands and thousands of stars in the Milky Way. An interesting thing to do is to pick out a star, travel to it, then see how the constellations deform as you're traveling to it. They even put in a few known exoplanets, so you can go to those solar systems, and see how they're set up (Gliese 876 b is a good one). Double stars, like Sirius, Alpha Centauri, and Mizar are also modeled.

Time acceleration is also implemented. Since a lot of things in space take a long time to visibly change position, you can make time run as fast or as slow as you want. You can also run it backwards.

Another interesting feature is the eclipse finder. This lets you calculate the times and dates of either solar or lunar eclipses within a specified time interval. It then lets you fast-forward to that date, so you can see what it will look like from space. It also lets you calculate eclipses for the moons of Jupiter, Saturn, Uranus, Neptune, and Pluto (not a planet, neener neener!).

Now, despite all the praise I've given it, there are a few problems I have to address. Firstly, if you're running Debian 9, you're fucked, because while Debian 8 and 7 included packages for Celestia, Debian 9 doesn't, for some reason. Plus, the linux binary distributed by the website is for an earlier version, it's x86 only, and it's in autopackage format (yuck!). You might think, "Well, that's not a big deal, I'll just compile from source, because I'm smart and know how to do that." Bzzt, no you won't! As of the time of writing, the current version of Celestia (1.6.1) does not compile from the source code. Even when you've installed all the necessary dependencies, there is a header file missing from the source code. So, you have to download a binary if you want to use this program. I had to install Debian 8 on a spare flash drive, just so I could download the package with the correct dependencies (that's why this review was late). Also, in my version, the textures for Mars, Jupiter, and the Moon were missing, so they just appeared as grey blobs (everything else looked pretty, though). So, if you're a Debian user, it may take some work to get this program running - I don't know if other distros ship a binary package for it.

That's the most I can do to describe this program in words. It can't really be described, though - it has to be experienced. Despite its flaws, I highly, highly recommend that you check out this program - just make sure that you have a few hours to kill! When I have some more time, I'm planning on recording myself playing, just to show off some of the cool things it can do. I'll post the video on this subforum.

And that's it for this week's Open Source Application of the Week. What should I review next week? Let me know in the voting thread (non-onion link). Thanks for reading, and I'll see you all next Monday!


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theblackcat wrote

Raddle could really benefit from image embeds for these reviews.

It sounds like a really cool program but it would help if we had screenshots.


sudo wrote

I agree; that's part of why I want to make a video for it. Here are some screenshots from the official site.


ziq wrote

These reviews are really the best tool we have to recruit new people to raddle.


chaos wrote

One of the best reviews yet, thanks!


alqm wrote (edited )

Looking at the screenshot reminds me of Orbiter Space Flight Simulator. I sent the developer a message suggesting him to port it to GNU/Linux and release as open source. He's a scientist (Martin Schweiger). He would understand how open source is beneficial to the world.


sudo wrote

Yes, I love Orbiter! But IIRC, he said he doesn't want to port it to Linux, and I think he said he wants to keep it closed source. But let me know what he says.


BlackFlagged wrote

Well this sounds freaking awesome, hope they make up to date versions soon.


Chomskyist wrote

How cool would it be if Celestia were adopted by future Spaceships to map the stars??


sudo wrote

They probably wouldn't need Celestia for that; there are already lots of star catalogs out there. The only thing it could be used for would be to display those maps in 3D (but maybe that's what you meant).