Back in the days when DSLR didn’t exist and CCD camera where really expansive, the only cheap way to start in digital astrophotography was to use a webcam.
But webcams usually don’t take pictures for a time longer than a 1/4 of a second. The basic of astrophotography is to take long exposure images in order to capture as much light as possible. So webcams were not a good candidate until Steve Chambers found a hack in August 2001 which enabled long exposure with a Philips Vesta webcam.
The modification pictured here is done on a Philips Toucam Pro II. It requires some soldering on really fine pins. I also added a fan to the back of the camera to extract the heat building on the sensor.
The camera is connected in USB and a second cable connects to a parallel port. On modern computers, this port is emulated using a parallel to USB cable.