How do you get night skies with long exposures?

Question

I'm really interested in shooting night skies with long exposures so the rest of the stars rotate around Polaris. However, I'm a bit confused...? If you set the camera to bulb and let it run, won't the photo become over-exposed? Is this an instance where a Intervalometer would be necessary? Or are those only needed for time-lapse?

Examples below.

http://fc05.deviantart.com/fs32/f/2008/211/4/5/45744dcb199bba27fee95fb910ec775d.jpg

Credit to p0rg @ deviantART for this photo.

http://p0rg.deviantART.com

http://farm1.static.flickr.com/222/522833394_2076f547e0.jpg

Credit to dennyt @ flickr

http://flickr.com/photos/dennyt/

Answer 1

You will have to do some tests ... adjusting the f/stops and ISO settings until you get the exposure you want.  Shooting in an area where there is not much ambient lighting will help a great deal

Put your camera on a tripod and place Polaris in the center of your frame and then open the shutter and lock it open until you have exposed the sensor long enough to get what you want.