Celestia Forums

I am a complete newbie to this space simulation game, although I have been worldbuilding for a few years now at Orion's Arm;
you can see my first ever Celestia planet here on this OA related forum (sorry, I don't have a home page of my own yet)...

the planet iself is described here.

I am interested in the terms of use of thes sorts of images, as there are many things in Orion's Arm which I could use Celestia software to illustrate...

On a more technical note, I had to use the Earth atmosphere PNG as I couldn't see how to manipulate the invisible image on this particular texture- it is white on white and I can't see what I'm doing(told you I was a novice)...

Ribblehead if real would probably have well defined convection cells , more like a gas giant, as it is considerably larger than Earth...
I am of the opinion that many terrestrial worlds will be larger and less dense than the Earth, as many will not have experienced the sort of impact that created our Moon.

Steve Bowers

Steve,

Just as with commercial paint programs, there are no restrictions as to how you use the images produced by Celestia.

For example, here is the response from Chris Laurel (the primary author) to a question about using Celestia in producing a movie: http://63.224.48.65/forum/viewtopic.php?t=1772

(Chris seems still to be on vacation, which is why I'm jumping in here.)

To answer your usage/design question, the cloud texture image can be either a PNG image or DDS texture file that contains an alpha channel. The alpha channel determines the transparency. The primary image determines the cloud coloration.

For example, the Earth cloud image that comes with Celestia is solid white and its transparency channel determines how it looks.

There are many ways two images can be combined into a texture with an alpha channel. I like to use ImageMagick, but layers in a paint program (like Photoshop) can accomplish the same thing.

I'm sure Don Edwards could give you some artistic pointers

Thank you; that is very encouraging.

Hello Steve

I had to look twice when I saw a topic in this forum titled 'Ribblehead'. I was thinking it surely couldn't be in relation to that beautiful part of the world not too far from where I live. The fact that the planet Ribblehead lies in the Pen-y-ghent system confirms that it is!
However I was amazed to read that all technology is banned from the surface of this planet, and all transportion is either horse drawn or by bicycle....surely there's got to be a railway?

BTW are there any more planets?, and if so, what are their names?

regards
TERRIER

Perhaps a steam railway or two;
the trouble with allowing a railway is that the cylinder boring machines can produce accurate artillery; this is supposed to be a low tech world...

There are dozens of detailed worlds in OA, and hundreds with less exhaustive descriptions; as I put them into Celestia I will let you know.

That 'city ring' seems way too close to be at the geostationary distance (unless the planet has an obscenely fast rotation rate - about 1.6 hours?!). It looks like it's only about 1000 km above the surface! (Earth's is about 36,000 km above the surface).

Um...

And your surface gravity is wrong too - should be 0.76 of earth's gravity with that density. If you want it to be 0.98 g, the density should be 4300 kg/m3.

I think I will change the density to your figure - thank you;
the planet was supposed to have a small iron core, but I couldn't figure out how to fudge the maths.

the city ring is dynamically supported at a low altitude using mass particles; this is an extension of Paul Birch's ideas about Dynamic Compression Members, which allows you to put structures at any height around a planet or star;
http://www.paulbirch.net/

eburacum45 wrote:http://www.paulbirch.net/

Thanks for posting this link. Birch's articles in JBIS were always interesting, and it's a shame he seems to have fallen out with the British Interplanetary Society so catastrophically, particularly when we see the topics he had planned for future articles.
Anyway, it's a fine thing to have his various pieces assembled in a single place for reference. Perhaps the model builders can create some of his complex solettas for us ...

Grant