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Long exposure Toucam guiding with PHD
I have been using the short exposure mode on my Toucam to autoguide with PHD. Works fine except for the problem of findind guidestars, so over the weekend I tried the long exposure mode. First night was a disaster--the image kept changing brightness from very dim to noising out completely. The next morning I read the help file and saw that you had to set a parameter "LE read delay", To quote from the help file:
---LE Delay: If you are using a long-exposure modified webcam there is a magic "delay" value that lets you grab the correct video frame (the long-exposure one) out of the stream of blank or short-exposure frames that come on before and after this long-exposure frame. Typical values are about 10-20 ms, but this will vary from system to system.---
OK, so the next night I fiddled with this parameter and at 11 or 12 ms delay I got beautiful star fields with a 2 s exposure. This was going to make guiding a lot easier! But when I tried to calibrate, nothing much seemed to happen; The little box around the star was there, the cross hairs showed up, but when PHD said things like "calibrating E", the box and star stayed put on the cross hairs, instead of moving off in the usual way.
For the rest of the night I went back to the short exposure mode and things worked fine.
Can anyone who has had experience with long exposure Toucam guiding give some advice?
Geoff
Last edited by Geoff45; 13-11-2007 at 02:34 PM.
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