WHEW! You guys really know how to debate topics.
My experience with Celestia in the classroom is excellent. I teach up to 180 high school kids at a time from ages 14 to 18, boys and girls. I conduct courses in both General Earth Science, and a dedicated elective course in Astronomy for juniors and seniors.
When I first tried Celestia in school, I wanted the kids to be able to use it personally ... at individual computer stations. I did not just want to use it myself on one computer and simply project it to them via LCD projector. What fun is that for them???
I feel that science should be "FUN". To us scientists, it seems obvious that science is fun. However, to a 15 year old girl in a high school with 3,000 students, studying about the moons of Jupiter is not exactly ... EXCITING! No matter how you present it, a moon is a moon!!! ... to a 15 year old girl
So what if the moon has volcanoes!!
As a result, if Celestia was to be used in my classroom to teach Astronomy, I HAD to get the kids into space personally ... on their own computers ... riding a spaceship of some kind ... visiting astronomical places AND doing something when they got there!
The initial computers used in my school in 2003 had Intel integrated graphics (pentium IV HP computers running Windows 98 ). Celestia 1.3.0 ran OK on them, but the frame rate was a bit sluggish. Since my school prided itself in being a "state-on-the-art" facility, I was able to talk my school principal into investing $3,000 to buy 30 Nvidia FX 5600 video cards. I put them into 30 lab computers myself. Those cards made all the difference in the world. With them, I am able to run Celestia 1.4.1 with over 1.5 GB of add-ons. Although the frame rates are dropping fast as new add-ons are used (down to 6 fps in some cases), I can still use Celestia to take these kids anywhere I wish.
You might wish to know that there is a LOT of technology grant money out there. Companies all over Earth are scrambling to have their names associated with some worthwhile educational project. Getting one of those companies to buy your school a few dozen video cards is not that hard. It just takes a bit of work in writing the grant.
One we had the cards installed, I tried letting my students explore on their own. It was a total failure. They zoomed around in space for 30 minutes or so, did very little actual work, and lost interest in Celestia (no explosions, sounds, animation, etc.). Instead, they just began to talk to each other/socialize. They were used to video games, and Celestia is no video game.
I realized that to utilize Celestia's true potential, I needed a tightly controlled, choreographed journey that allowed them to fly through Celestia space, but in a direction and at the pace I wanted them to go. I needed an easy way to convey what controls and keys to push. I needed to show them exciting things. I needed to tell a story as we went. I needed to TEACH them astronomical facts along the way. I needed to give them a detailed worksheet to complete ... to record facts and keep them busy. I needed their minds engaged at all times ... to minimize socializing and talking ... preferably by requiring them to read something!
In short, what I realized I needed was a written "Activity" document ... a written guide that would take them through the complete Solar System, or on a trip through the life cycle of stars ... or back in time to watch the formation of Earth and Moon ... or a voyage of discovery to see the many spacecraft that we have launched into space.
Obviously, these trips required add-ons ... lots of them. They required an enormous amount of work to design and write. Where does one go in space? What do we see when we get there? What questions do we pose for the kids? Is there any action ... explosions ... sound effects ...??? What add-ons are available? If one does not exist, can such an add-on be created?
The result of this effort are the 12 educational journeys available on the motherlode education page. In my experience, my students honestly ... (I'm not just saying this .... ) LOVE THEM!!!! They are actually engaged for hours at a time in a dark room ... flying through space. They read the document, learn thousands of space facts, complete worksheets ... experience the universe. They get to see their own spaceship from the exterior and interior. They hear spaceship sounds, rockets and warp drive engines. I even have wind blowing on Earth and Jupiter, and volcanoes rumbling on Io. In short, they are engaged ... in a kind of astronomical video game! It WORKS!
I use some special tricks to keep them that way. One trick is music. I stream in a space music radio station into the computer room at all times. It plays ethereal music in the background. I play it quite loud. That makes the kids a LOT less talkative. It reminds them of being in a movie theater with music playing in the background. They don't talk at all when the music is playing. Rather, they really get into it!
Another trick is to take them to the best places Celestia can offer. To do that, the Activites use over 100 add-ons, with over 400 cel:urls. Many of the add-ons were designed for me by forum members specifically for this educational use.
A third trick is to remind them that without Celestia, they would be listening to me lecture
My, how that brings them back to reality!!!
A fourth trick is to use the written Activity documents to teach the kids what controls to press. As they keep reading the same instruction over and over (press the "A" key to accelerate), they do slowly learn over 40 key commands.
In summary, Celestia can be a spectacular teaching tool. In fact, it is the most amazing and engaging educational tool I can imagine. Without it, I would stop teaching Astronomy.
FYI
Frank