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Subject: [M]: RE: CCD planets?
From: Michael Hart
Reply To: mapug@shore.net
Date: Wed Oct 23 02:14:54 1996

Bruce Segal wrote on 10/22/96:

>I have a 12" lx200 and pictor 1616 ccd. Last night I took pictures of
>Jupiter for the first time and could only get a small featureless
>disk.

What focal ratio were you using? I have a 12" LX-200 and use f/20
to f/30 or MORE which increases the exposure time and image size.
I'll bet your image is WAY overexposed. Open PictorView 2.0 and load
your Jupiter image. Bring the cursor over Jupiter. Note the readings
that are indicated in the lower bar just to the left of the time. If your
getting 65,000 everywhere on the image, you have overexposed
your image.

> The automatic exposure with an IR filter was 7 msec.

My experience has been to keep exposures above 10 msec to assure
repeatability.

>The camera was cooled but not guided.

At millisecond exposures, you don't have to guide.

>This was optimal focus. The disk was small relative to the exposure.
>Changing exposure time didnt help.
>What went wrong?
>Thanks, Bruce.

Michael Hart
mhart@netexpress.net