Modified Webcam for astronomyThe images of Mars, Saturn and Jupiter above were captured with a cheap and simple web camera mounted on a telescope. I found a lot of good information at http://www.qcuiag.org.uk/. There are many enthusiasts that have explored this kind of astronomy and contributed with ingenious ideas.
With a web camera you can capture sequences with hundreds of images in a few seconds. Special software is then used to evaluate the quality of the images by analyzing their frequency content.
Images are sorted automatically in order of quality. The variation is usually very big as atmospheric disturbances are a major source of degradation. You then enter how many of the best images you like to process and let the software do the job. The software calculates a final image from the data of your sequence. The software I use is called k3ccd and can be found at http://www.pk3.org/Astro/k3ccdtools.htm.
The webcam that I modified is a Philips Toucam. It has a Sony CCD sensor while newer webcams are using CMOS sensors. The modification does not need to be complicated. All you have to do is to remove the lens and make a mount for the telescope. The camera is used in prime focus (no eyepiece used).
I did a little bit more with my camera. A new housing in aluminium with cooling fins was made. I also installed a Peltier cooler and made a minor hack in the power supply to the camera so the amplifier can be turned off during long integration times. A thermometer was also built in to show the temperature of the sensor. You really don't need to do anything of this if you are just going for planetary photography as the integration times will be short and dark current is not a problem.
|Nikon bayonet mounts are used to connect the parts. At the first level the bayonet surface is very close to the sensor surface. Next module ends exactly where it should to bring a Nikon lens in focus on the sensor. And finally an adapter that fits the telescope's eyepiece tube is attached (top of the page). The eyepiece tube adapter can of course also be mounted without the middle module in place in order to bring the sensor closer to the telescope.|
The camera mounted on a Celestron C8+ telescope. The tripod is originally for a movie camera. Legs of wood are good as they vibrate less than metal. Some small changes and it was perfect for the telescope.
Unfortunately I don't have a permanent observatory so this case was made to make transports easier. And there are a few homemade accessories in the case...