HEART OF THE SYSTEM, THE CCD CHIP
The image sensor in a CCD camera is the CCD chip. Many consumer digital cameras use the same or similar chips. These chips range in size from 2 to 3 millimeters on a side for the less expensive cameras to 2 inches or more on a side. The chips contain arrays of pixels (light sensitive spots) from appx. 128 x128 pixels up to 4000 x 4000 pixels or more. The pixels themselves range in size from about 4 microns to about 30 microns. CCD, by the way, stands for charge coupled device.
HOW DOES IT WORK?
The CCD camera is mounted on the back of a telescope (or even a camera lens) and the image formed by the optics is projected onto the chip. Light striking each of the pixels on the CCD chip is converted to electric charge. This charge is greater where there is more light and less where there is less light. At the end of each exposure, the charge on each pixel is read by the computer and the picture is formed. During this exposure the telescope must track the stars VERY precisely. In fact, the most important part of CCD imaging is a good telescope drive.
WHAT KIND OF CAMERA DO YOU USE?
I have used five different cameras, most made by Santa Barbara Instruments.
The cameras I have used are:
CAN I USE A REGULAR DIGITAL CAMERA?
It depends. For bright objects, a regular digital camera may work fine, especialy a DSLR that can be adapted to a properly mounted telescope. For dimmer objects that require long exposures, a specialty astronomical camera with a cooled CCD chip will probably be needed.
HOW ARE THE IMAGES PROCESSED?
Newer images are collected and the camera controlled using MaxImDL. The images are usually processed using PhotoShop, CCDStack, and PixInsight. Older images may have been processed using a variety of older software.