Jupiter Index.
Techniques.
Your telescope should be in optimum condition for planetary imaging. Check and recheck the collimation of your system before starting, especially with SCT's. Wait until the telescope has the same temperature as the surrounding air. Check the seeing visually, don't image if turbulence is bad - it's a waste of time.
For planetary imaging, you need a long focal length. On film this means using either barlow projection or eyepiece projection. This also means low light levels and long exposure times (2 to 7 seconds) so that good results on film are very difficult to obtain.
This is different with CCD camera's where you can use a shorter focal length (aim for 0.5 to 0.25 arcseconds resolution per pixel using one or two barlows) and shorter exposures due to the higher sensitivity of the CCD. So you can make a lot more images in a shorter time than is possible with film. Download time of the CCD images due to the use of a parallel cable/port is slow which limits the number of images (this will improve a lot with cameras using USB to connect to the PC!).
Focussing is difficult, take your time and learn to assess when the image on the screen is sharp (raw images on the screen do not always look sharp although you are in focus)
Enter the webcam: a very simple device that is capable of outstanding results due to the fact that such cameras have small pixels, have good sensitivity and by "filming" the planet you make hundreds to thousands of images in a short time. The rest is patience in checking for the best pictures and combining them with software (Registax, AutoStakkert...).
For Jupiter, you should take the images to be combined within one to three minutes, otherwise the fast rotation of Jupiter will blur details.