Views from the Ground

     Here's a problem for y'all to tackle:  Does anyone know of a program
(or at least the necessary formulae for writing such a program) to
determine what the view looks like of an arbitrary solar system from the
surface of one of the bodies within that solar system at a given time?
     For instance, consider the Regina system.  It consists, first of all,
of a trinary star system.  One star is the primary, one star is a brown
dwarf orbiting the primary at close range, and the third is a far companion
orbiting the primary at a range beyond the orbit of the outermost planet.
     In orbit about the primary (and its brown dwarf companion) are 5
planets, including 2 gas giants.  In orbit about the far companion are 4
planets, including 1 gas giant.  Two of the planets orbiting the primary
have satellites, one with 3, the other with 5.  Similarly, two of the
planets orbiting the far companion have satellites, again, one with 3 and
the other with 5.
     Regina is one of the satellites orbiting a large gas giant that orbits
the primary.  So, if you were standing on Regina, looking up into the sky,
what would you see?
     Presumably the other planets wouldn't be visible, at least not as
anything other than points of light.  But what about the other 4 satellites
orbiting the same gas giant which Regina orbits?  How well would they be
visible during the day?  During the night?  What about the gas giant
itself?  How large would it appear from the surface of Regina?  What
about the primary star?  What would it look like at that distance?  Would
it merely be an exceptionally bright star, or would it look more like Sol
does from Terra?  The brown dwarf would presumably be invisible in the
glare of the primary, but what about the far companion?  Furthermore, how
much light does Regina receive during the day?  When the primary disappears
behind the gas giant, as it probably will every Reginan month, the primary
is eclipsed.  How long does that eclipse last?  Presumably far longer than
the eclipses we have here on Terra.  That could be a VERY significant
feature of Reginan life (and covert actions).  And when it is night and the
gas giant is in the sky as a "full planet", how much light is reflected
onto Regina?  Is it a "false day"?  If so, that too would have a
significant effect upon how covert actions are conducted, as there would be
a period of each month in which the cover of darkness doesn't exist.

     I know that there are programs that show the positions of the planets
in our solar system or how the night sky appears at various times, but I
haven't seen anything which allows the user to enter data about an entirely
fictional solar system and then pick a location from which to see the view.
Having a picture of the view would be nice, of course, but all I would
really need would be a text description of the situation.  Any suggestions?

P.S. By the way, I think I'd be interested in helping with any MT GM aid
program writing.  My only problem would be finding enough time to do it,
but count me in for now.