Question: I just started radio telescope observation, and wanted to know how to use a computer to capture actual images or similar with a radio telescope. I am just using an old TV dish with a satellite receiver and LNB, but I still hope I can use it to capture images. How do I plug it in the the computer and use the computer to capture images from the telescope? — John
Answer: Radio telescopes are just like optical telescopes in that the parts of these telescopes that produce images are actually the detectors that are placed at the focal point. Optical telescopes use array detectors, such as Charge Coupled Devices (CCDs). Radio telescopes can also use array detectors to produce images, but these array detector systems are often much more complicated and difficult to make. The most straightforward way to make a radio image with your satellite antenna system, then, is to use an array detector, which I believe would be very difficult to find. Alternatively, one can make an image by pointing an antenna to an array of nearby positions on the sky then creating a contour map of the measured signal strength. This is a rather slow process, though, that only produces an image much later, after you have gathered all of your individual pointing measurements. Remember, though, that you can do quite a few interesting measurements with your satellite antenna and receiver system. You might take a look at the web site of the Society of Amateur Radio Astronomers (SARA) for some ideas for measurements that you might try.