hi Gabriel
here is a great tutorial written by Mike on how to do nightscapes (camera and lens) the same concepts will apply no matter the camera you use.
http://www.mikesalway.com.au/nightsc...phy-101-intro/
for a telescope you will need a t mount and t ring to attach to your telescope. as mentioned below you will need to set it to bulb mode to shoot (i'm guessing) past 30 seconds.
good luck
Rusty