Canon

Taking pictures of the night sky almost always involves exposure times that are more than 30 seconds. This is often couple with taking many pictures for later stacking into better images.

For this, the camera has to be set to Bulb mode. You can automate taking multiple exposures by using an intervalometer, which is a remote release with a device with some electronic circuits and LCD screen to make all this possible.

You can also automate this using a Linux computer running gphoto2 software. The computer can be as small as a Raspberry Pi, or a laptop.