You no longer need expensive CCDs to take astrophotographs. You can use a webcam! Lots of cool things are happening, but it all started at the QuickCam and Unconventional Imaging Astronomy Group (QCUIAG).
Most webcams today use CMOS sensors which are not suited for astro work. But some old quickcams had a CCD in it. These include the Vesta and ToUcam webcams among others. Some people have figured out how to modify the electronics to get them to make long time exposures. However when you have very long exposures thermal noise saturates your picture. Two ideas were developed to remedy this.
The classic solution is to cool the CCD. This has been done by many, but it is difficult to do. The second method is to stack a whole bunch of individual exposures. This gives a resulting image much better than any single one. Software like RegiStax (freeware) does this, and very well. You don’t even need to modify your webcam’s hardware to do this. Just make or buy an adaptor to fit it to the scope. So webcam astrophotography actually begins with the right adapter to fit the webcam to your telescope’s eyepiece holder. Steven Mogg makes them.
I am enclosing a picture (above) of the moon I took a few days ago with my ETX 90 telescope and an unmodified Phillips Vesta web camera with a Mogg adapter. Each picture is the integration of some 60 shots.