Tips for taking night sky photography?

That's the nice thing about digital, you can practice and see results right away.

In addition to a tripod, you will need a remote shutter release so you don't vibrate the camera when pushing the button... as well as for long exposures as most entry level cameras can only be set for as long as 30 seconds. If your camera has a mirror lockup, use that so it won't vibrate either.

Pretty much all night sky photography is done manually. Forget autofocus as it will get confused, and automatic metering will leave you with a brown sky full of noise and washed out stars. Stars are very bright, and you don't want the sky to be exposed at all.

Set your focus manually to infinity. This can be difficult with autofocus lenses as most go past infinity (and of course aren't marked). You can use live view or the viewfinder to focus on a distant street lamp and it should get it close enough. Shoot with the aperture wide open to get as much light, but keep the ISO down or it will get grainy.

How you shoot the night sky depends on what you want to portray. If you just want a star field, you will need to limit the exposure time to 30 seconds or they will start to form trails. If you want star trails, exposure time will be in the hours.

Keep playing with aperture, exposure times, and ISO until you get the results you want.

For star trails:

http://www.danheller.com/star-trails

For astrphotography:

http://astropix.com/HTML/I_ASTROP/TOC_AP.HTM

http://www.popphoto.com/how-to/2008/12/how-to-astr...

The farther away from any souces of light pollution you can get the better.