Moving the moon closer to earth?

[Hugo Rune]

Hi all - bear with me here, I'm new to Celestia (and do believe that I'm in love with it)..

Anyway, is it possible to move the Moon closer to the Earth in Celestia?
I've modified the file solarsys.ssc and changed the moons SemiMajorAxis to any amount of different numbers, but nothing changes! I changed the radius of the moon and *that* worked, but I can't figure out how to get the damn thing closer!

Any help would be apprieciated - my kid's just started science at school and she doesn't believe that the moon is so small in comparision with earth so I thought that I'd show her that it really *is* that small.

Thanks in advance everyone!

[Hugo Rune]

I've tried moving all the planets closer together so I can view all the planets close up, and show their different sizes in relation to one another, but this too doesn't work.

Does Celestia check it's data and go "Nah, that's not a valid solar system" or something?

Sorry for the dense questions. I'm sure it's something obvious. Can I find it? Can I expletive!

[granthutchison]

CustomOrbit takes precedence over EllipticalOrbit if a CustomOrbit is defined in the ssc - it effectively converts the EllipticalOrbit entry to mere illustrative data.
So if you want your modification of the EllipticalOrbit spec for the Moon (or the planets) to bite, you just need to comment out the preceding CustomOrbit by putting a "#" in front of it, like this:

Code: Select all

   # CustomOrbit "moon"

and so on for the various planets.

Grant

[HankR]

Hugo,

Did you remove the line:

CustomOrbit "moon"

from your 'solarsys.ssc' file?

- Hank

[Hugo Rune]

See solarsys.ssc file here. I'm being dense, I'm sure of it..
http://www.design4online.com/hugo/solarsys.ssc

[Hugo Rune]

Ah, no. I didn't do that..

Lets see what happens. Thanks guys..

[Hugo Rune]

That worked a treat!

Thanks a million!

I must say, out of all the software I've ever downloaded, this is one of the best.

Thanks again..

Hugo

[granthutchison]

Anything for a Robert Rankin fan.

Grant

[bh]

Hugo...sorry I might have missed something...why move the moon closer to Earth?

Regards...bh.

[Hugo Rune]

heh..
Well, I wanted to move the Moon closer because my kid has just started science at school and she's now dead interested in astronomy (thank God the Barbie phase is over!) so I thought that I'd help her out, being a total astronomy and sci-fi nut..

So she was asking me how come the moon looks so big sometimes. I explained that it's an optical illusion - it's merely the horizon that makes the moon look big etc etc etc but she was having none of it.. So I wanted to show her what the moon would look like if it was a lot closer (and now I can, thanks guys). Thats all.

I also think that I'll make an Earth/Moon flyaroud movie at some point, and it's good to get the moon closer, just for cinematic effects

And granthutchison? If you're a Rankin fan too, then I salute you! Just dont blow up my dog, Biscuit

[fsgregs]

Hugo:

If your daughter is getting into Astronomy and is of middle school age or older, you/she might want to check out the Educational Activities we of the forum community have been developing. Although I wrote the ones that are currently available, they really have been a joint effort of several talented people. You can find some of them on my website (click website button below). They require the downloading of add-ons (sometimes big ones), but the add-ons will only enhance your Celestia experience and can be left on your computer permanently. I suggest Activities 3.2, 4.2 and 6.2. They take you on a comprehensive tour of the inner and outer solar system and the life cycle of stars. Read-me files are included with each one.

I hope you and your daughter enjoy them. Other Activities will be posted on my site soon.

Enjoy.

Frank G

[selden]

Hugo,

HarrieS, a guest in the Development Forum, just made a posting there suggesting this simple experiment:

Here is something you might try: a finger at arm's length is about two degrees wide for most people. That means that you can fit four moons side by side. Go outside and check it. Now have a direct look at your finger indoors. Can you still believe that four moons will fit on it?

I suspect your daughter's finger is somewhat smaller, but the idea is still the same.

Does this help?

[granthutchison]

I suspect your daughter's finger is somewhat smaller, but the idea is still the same.

Her arms will be somewhat shorter, too . Unless kids' arms and hands are out of proportion to adults', the demonstration should still work as advertised.

Grant

[AuReality]

I also think that I'll make an Earth/Moon flyaroud movie at some point, and it's good to get the moon closer, just for cinematic effects

And it is!
Being able to see this big earth rise while on the moon is just great.
I can imagine something similar for the whole solar system, to do an easier size-comparison than the script that does this. (no bad words about the script, but it's just impossible to get all planets in one view and then compare their sizes. The distances are just too large.)

Paul