THE 1004x JG CCD ASTRO CAMERA
BRIGHT STAR SHADOW REDUCTION
For reasons which are not fully understood, the 1004x camera in its standard form produces dark trails or shadows to the right of bright stars. These are not normally noticeable against a dark sky background, but become objectionable for stars embedded in bright nebulae. After much experimentation using an artificial star light source, a solution which reduces the effect significantly, without significantly affecting the sharpness of the image, has been devised. This appears to be a reproducible solution as it has proved to be effective on Jon Groveís camera too.
The modification consists of connecting a 3.3nF capacitor across the video output from the camera. This same value was found to be effective for both my and Jonís camera. The pictures below show the results of the artificial star tests and the results on a deep sky image of M27. Note that the shadows are to the left in the M27 "before" image as the camera was rotated 180deg between the two images.
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