Night time shooting with Digital camera (Canon)?

I've got a Canon D400 and would love to try and take photos at night. i.e. stars. I've had a look at Flickr and the type of shots I'm after require an exposure time of around 120 seconds, but the maximum exposure time I can get on the Canon is 30 seconds.

Can I achieve these settings or are they unobtainable?

Yes you can do exposures longer than 30 seconds. Your camera has a Bulb Mode which allows you to keep the shutter open for as long as you wish, by holding down the shutter button. Expect noise levels to increase though. Bulb mode is accessed by turning the mode dial to M first.

Look up 'Bulb Exposures' in your user manual's Index...

maybe rainy clouds r canopying the sky, hiding the stars.

I don't think you can, the longest exposure is as you say 30 seconds, however you may find that using the camera in night mode with no flash and exposing for various lengths of time may give a similar result. The take up time for exposure on digital is not the same as film. Have a couple of tries with different shutter speeds - good luck

Is there a "B" or "T" on your shutter speed dial? If so, you can set that as your shutter "speed" and use a cable release to hold the shutter open as long as you want. That should be explained in the Owner's Manual for your camera.

Here is a word of caution concerning long exposures with digital cameras. It is from the FotoSharp (fotosharp.com) "Day & Night Exposure Guide".

"If you use long exposure times, shoot at high ISO settings or let the camera get too warm, "noise" or colored specks will appear on your images. Computer software can be used to remove noise; however its best to reduce "noise" when you're taking photos by:

*Setting the camera to the lowest ISO setting available
*Using the camera's noise-reduction feature if it has one
*Keeping the camera cool
*Taking long exposures as soon as you turn the camera on
*Turning the camera off between long exposures to let the sensor cool down