I haven't a clue if this will give you any satisfaction:
http://www.subsim.com/radioroom/showthread.php?t=117216
and
http://www.subsim.com/radioroom/showthread.php?t=116170
Some of the posts overlap what I listed above. Some of the folks back then seemed to think that the stars were "accurate" in SH4. I have no idea what their idea of "accurate" is... The moon isn't, the sun isn't, time isn't, the world is "flat" on a cylinder, but ya never know until you try 'em. I'd make a "spare" copy of the game to experiment in though...