Shooting the planets with a webcam

The quality of your final image will be limited by the weakest link in the chain that goes from the photons entering your telescope, to the planet print on your wall.

The weakest link is the atmosphere, but, unless you bought a space shuttle at an auction, you have mostly no control on it.
The best you can do to limit atmospheric turbulence is to avoid the proximity of buildings, and observe from your lawn.

The second weakest link is your telescope, it hosts a lot of gremlins.
To stress the most important points :

The next link is the amplifying device you use to form the image (nothing, barlow lens, eyepiece projection, ...).
To get all the information you expect from your telescope, the detector shall have a sampling frequency at least twice the highest frequency in the image (Shannon theorem).
That means that the pixel size must be less than half that of the Airy's disk on the resulting focal plane. In other words, you must use a focal/diameter ratio higher than f/D = 3.44 x p where p is the pixel size of your webcam in micrometers. Ex : for a ToUcam with 5.6 µm pixels your optical setup must be at least at f/D = 19.
This is not only boring theory : I was reluctant to use eyepiece projection for my first tries with a webcam and used a barlow lens with which I attained f/D=9, and the results where encouraging... The day (no ! the night) I used eyepiece projection to obtain f/D=20, I regreted I had wasted so much time gathering bad images !
This must be pondered with the fact that the exposure times must remain short enough to freeze the turbulence (1/20 sec at most).

Having the right image scale is not enough, the image must be very precisely focused.
The internet is full of techniques to achieve "perfect focus". I have no preferred one. All I have to say is that it is not easy, and of prime importance

The next link is the webcam.
To send large images at a high frame rate across a USB® link, the webcam compresses the images with some losses. These losses are not like random noise, they tend to form artifacts that are eventually enhanced by processing.
To avoid these, use the lowest frame rates possible (I use 5 Hz) and, if you can afford to increase your focal length, lower frame sizes.
Another option, I'm considering, is to use a FireWire® webcam.

When you master all the issues described hereabove, you will have no troubles getting great pictures of the planets.
On the contrary, if you don't care, no software will help you.

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