High!

I implemented Thomas de Groot's suggestion for my Saturnian system model 
(and will do this in the future also for the other planets, which also 
all have some axial tilt) and started with rendering two views of Pan, 
the innermost regular moon of Saturn (except for some 150 tiny 
"moonlets" orbiting still more inward), from 5,000 and from 100 kms.

To get the camera centered on Pan, I had to rotate its location and 
look_at vectors according to Saturn's axial orientation using vrotate():

     #declare Final_Pos_Pan = Pos_Saturn + vrotate(Pos_Pan, 
<bodies[3][4]-(90-bodies[72][10]), 90-bodies[72][11], 0>);
     #declare camPos = Final_Pos_Pan + 100 * <sin(radians(39)), 0, 
cos(radians(39))>;
     #declare camLook = Final_Pos_Pan;

Note that the camera still looks towards Pan from the ecliptic plane, 
which is identical with the x-z plane; later on, I will use the 
respective planet's (or moon's, in case of axially tilted moons like our 
own Moon) equatorial plane as reference for camera positioning.

When zooming close to Pan, I had to divide the global scaling factor 
(normally 13347) by 100, otherwise it would have been rendered incompletely.

A real flaw is that Pan doesn't orbit within the Encke gap (see 
http://en.wikipedia.org/wiki/Pan_(moon) ); I assume that this is caused 

(or, as well, inaccuracies in building multipartite texture_maps from 
them). Perhaps, in the more distant future, I'll replace this simple 
"monolithic" ring by thousands of individual ring objects, thus allowing 
individual thicknesses, corrugations and dynamic clump and tidal wave 
structures.

Also for now, the moons are simple spheroids rather than realistic 
asteroidal/small planet bodies with a real surface relief; for most of 
Saturn's (and the other planets') small moons, the surface structures 
would be entirely or mostly fictitious, with only vague hints at shapes 
gleaned from Voyager, Galileo and Cassini probe photos.

See you in Khyberspace!

Yadgar

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