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Old 30-03-2009, 02:40 PM
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higginsdj
A Lazy Astronomer

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Overcoming timing issues

Hi all,

Ever since picking up my second hand parallel ST-8E I have been plagued by timing problems. The Camera stole all the cycles from my PC and my PC clock (and thus the imaeg timestamps were 'off'. I recently looked at the log of time synchs recorded over the last 3 years of observations and was shocked to see errors as high as 650 seconds. In recent times The typical error was up to 25 seconds with the average around 1/2 this.

Well it turned out to be an issue with 2 settings. the first was the Parallel port BIOS setting and the second was the Image download priority set in MaxIm. I now use a BIOS port setting of EPP and a LOW priority setting in MaxIm and all my timing issues seem to have disappeared. Worst error so far is 0.6 seconds with an average und 0.1 second - I can do Astrometry once more (If I was so inclined).

Cheers
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Old 30-03-2009, 03:32 PM
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rogerg (Roger)
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Very interesting. Thanks for the post.

I haven't had such problems with my PC + ST7 (parallel) but know someone how has issues on a computer with timing. They have to correct minutes every day. I wonder if they have any port operations which might be causing it.. hmmm.
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Old 31-03-2009, 07:21 AM
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higginsdj
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I should point out that time synch is performed every 1 minute. Originally it was every 15 minutes (with the big errors). Assuming the fix 'holds' then I should be able to revert to 15 minutes again.
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