Celestia Forums

Just brainstorming again, like I tend to do ;)

1. Would it be possible, for the benefit of lesson planning with Celestia, for people writing scripts to be able to make "tooltip" type paragraphs that pop up automatically or at the press of a particular key, for any astronomical object, area or event that they plan on using in the lesson? This would allow them to write more specific information, commentary, or perhaps mini-quiz questions directly into the lesson, and activate them at the appropriate time. It would be even more useful if it were possible to allow the student to answer the questions (fill in the blank or multiple choice). You get my meaning.

2. It'd also be nice to have the ability (if you're a teacher using this program in combination with a projector) to draw circles and arrows and things of this nature right on the screen at will to highlight your points as you give lecture or narration or what have you.

3.Gravity: I know that Celestia does not use newtonian mechanics or relativity or whatever to do gravitational effects, and I assume that this would require a massive supercomputer to do properly on any decent scale, what with all the millions of things in our own solar system and soforth, however: Would it be possible for gravity to affect the USER, that is the point where your camera is in relation to a body? Or perhaps user-controlled objects, like a couple of spaceships or something, which would allow course plotting and orbital entry or what not, or would be used to illustrate gravitational principals.

My idea would be something like this: Earth, for example, wouldn't have any gravitational effect on the moon, but if the user were to approach within whatever distance you have to be in to be caught by the earth's gravity, it would affect him, or his objects. The moon and earth might then have a pull on the camera if you moved even closer, and thus it might be possible to demonstrate LaGrange points or something. I don't know that much about all of this so I hope what I'm saying makes sense. Basically, instead of trying to make everything have gravity, just make objects have a "gravitational domain" which when the camera falls within it, the object's gravity has an effect on the camera.

Size_Mick wrote:Would it be possible for gravity to affect the USER, that is the point where your camera is in relation to a body?

I have in fact tried that a few month ago, but wasn't happy with the results (and didn't try very hard). One problem is this: on the one hand you want to speed time up quite a lot, otherwise it could take a while until you even notice you are moving. OTOH gravity is most interesting when fairly close to planets or moons - which themselves move pretty fast with such a high timefactor. So you want to be close to fast moving planets, which introduces quite a lot of computational errors, and your simulation quickly starts to diverge from reality, sometimes in pretty unpleasent ways (oops, why is the observer suddenly in the planet?).

Maybe it's possible to use a different frame of reference, i.e. compute your position and speed relative to the next planet, and get rid of these problems - furthermore it may be a good idea to slow down time if the precision starts to suffer to much. But a naive implementation doesn't work to well - it's sufficient to do some simple flybys, but not good enough to follow the path of spacecrafts or other interesting stuff.

Harald

Dear Size_Mick:

It sounds like you are a teacher using Celestia in your classroom. That's great. As you hopefully know, there are a bunch of us teachers who use the program to greater or lesser extent. As a high school Astronomy teacher, I have developed an Education webpage for Celestia. On it are posted a series of 8 - 10 "journeys" through the Celestia universe designed for classroom use and ranging in time from 1 - 4 hours each. See the sticky thread titled "Celestia Educational Activities - Get them here" at the top of this forum section.

Other educators have also begun to design scripts that take the user on a short journey to a particular time or place. The script text that appears is limited but the script can highlight lots of interesting places fast, and can now be paused by pressing the spacebar (Celestia 1.3.2 and later).

If you have written any lesson plans that use Celestia, I would be happy to post them on my website for other teachers to use. This summer, I plan to make the site pretty, with a real background, possibly some flash animation, etc. If you have lesson plans that we can all read or scripts that you have designed, and would like to make them available on my site, please let me know and e-mail them to me.

To address your question, script designers are beginning to build keystroke entries into their scripts, so that the script pauses and waits for you to hit a particular keystroke. I can foresee the ability to have popup boxes available in Celestia which display a fact about the object, is not that far in the future. To the best of my knowledge, however, scripts cannot yet do that. Drawing in real time on the screen is another feature that only Chris Laurel and developers can comment on. I have no idea how long it would take to code, but I like the idea. That said, I once ran across an accessory program from another vendor that runs in the background and has the ability to highlight anything that is displaying on the screen. I can't remember its name, unfortunately.

As to gravity, it might be useful to have as a feature, but I have found that gravitational force computations, Kepler's laws, Newton's laws and their practical application to celestial mechanics tax the ability of many students to understand and use, at least at the high school level. You have to have a high level honors class if you expect more than a handful of kids to make the effort to grasp the material. If you are teaching college level, then I could see gravitational effects being worth the time of programmers to develop in Celestia, but at the high school level ... I have my doubts.

Anyway, welcome to the forum and I hope to hear from you.

Regards,

Frank G

I'm more of an armchair student. I would probably just look at lessons posted on the internet for the sake of educating myself, and because I like the very idea of the existence of this program.

It's hard to explain, but for a person my age at least, it's a simply fantastic idea that Celestia even exists, let alone is available for free downloading. So I tend to think about it a lot, but the only things I can really contribute are little brainstorms like this, in hopes that someone who actually knows what they are doing finds something useful in them. Probably more than half of what I say is either garbage or already thought of, but I figure if I can contribute one useful idea that you guys latch on to, then I've made my own small impact on the direction of development.

So just the other day I was thinking about all the stuff you can do with normal overhead projectors, plastic overlays, and those grease pens, with circles and arrows and stuff, and of course you see all of this done by your tv weatherman or replay analysis sports commentator, both of whom are using some sort of computing to get the job done. I figure it'd be a nice thing to have built-in to Celestia.

Dear Size_Mick:

Thank you for your contributions. Your ideas are all good. Its too bad you're not a teacher. You have the enthusiasium that good teachers should have. Keep the ideas coming, and if you have any surfing time, see if you can locate that program that draws a pen mark on top of any other program screen that is running. I know it was also free, but I can't remember where I saw it or how to get it.

Now you've got me/us curious. What age are you?

Frank

Probably you mean DeskMarker from http://www.deskmarker.com which is free for personal use.

Unfortunately it won't work with Celestia, as Celestia redraws it's screen every few milliseconds. I think no external solution will ever be able to draw resistent lines inside the Celestia main windows. Only a Celestia-internal routine could do that.

maxim

Maxim:

Thanks for the website. Its too bad deskmarker will not work within Celestia, but it is a useful program to have anyway.

Frank

fsgregs wrote:
Now you've got me/us curious. What age are you? :?:

Frank

Heh, I'm in my early 30s. The reason that Celestia is so fantastic to me is because I'm old enough to remember when there were no personal computers and certainly no publicly available astronomical software. The best one could hope for back in the seventies when I was growing up was to live very near a good planetarium, or to buy one of those very expensive mini-planetariums out of the toy section of the J.C. Penney cattle-log.

Now here it's 2004 and ever since "Ssystem" we've had some pretty amazing stuff available to us (we, the computer-buying consumers). But I never really dreamed that such powerful software as Celestia would be available to anyone but universities or private companies. That's just freaking fantastic! Best of all, I think Celestia can help people understand astronomy in a way that no other educational tool has been able to in the past, because it's so visually oriented. I shouldn't wonder if it's about 100,000x easier for teachers who know the program well to illustrate principals of astronomy to their students. And if a student remains mystified by something, he or she can easily view the same event or object multiple times and from different angles and speeds. Incredible!

Size_Mick:

Yes, Celestia has the most amazing ability I know of to bring students into space and finally let them explore the universe in their own ship. I teach Astronomy to 160 high school kids a year and I would NOT teach the course at all if I/they did not have Celestia at my disposal in a computer lab (each student gets to use their own school computer).

If you can, try taking some of the Educational Activity journeys I have posted on my website. They take you to some great places, while teaching some Astronomical principles in the process.



Frank