Orrery by Ken Young is an astronomical application which displays the night sky, along with (optionally) such things are the galactic plane, etc. Constellations may also be shown.

Release notes:

Changes:
* Added a Planet Compass (on opts menu)
* Added dates of major moon phases, for 17 lunar months to the Sun and Moon Information page.
* Very minor change to the moon calendar, which makes it highlight the labels corresponding to the current (UT) month and day

Bug Fixes:
* Fixed a bug which occasionally caused the screen to display all objects collapsed into a small area at the upper left of the screen after unzooming.
* Slightly improved the accuracy of sunrise and sunset times. I was off by 10 arc minutes in the position of the sun’s limb, corrected for refraction. This could produce an error in the
sunrise/sunset time of about 1 minute in the worst case.

http://projects.openmoko.org/forum/forum.php?forum_id=824