To use this simple calculator, you need to check the specifications of the CCD chip for your camera that comes with the manufacturers specifications. When entering the focal length you must take in to account any focal length shortening (reducers) or barlow lenses etc that alter the telescopes effective primary focal length.

For non-square CCD arrays you'll need need to enter the values for pixel size and number of pixel for each axis of the array to get a final "A" x "B" field of view result. For example, our GSTAR-EX camera yields a view on a T.V monitor roughly 20 x 14 arc minutes with our 10-inch SW252 Sky-Watcher Newtonian.