PHD2 Problem [Deep Sky] Acquisition techniques · Haakon Rasmussen · ... · 6 · 228 · 0

HRasmussen 0.90
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Hallo Astrobin members,

i have a issue that's causing me problems. But first my setup: TS-UNC 8" Newtonian, HEQ5 modded, ZWO OAG with 120MM mini, main camera ASI294MC Pro, Software APT 4.00 , PHD2 2.6.11 using multi star guiding. The problem is as following: When guiding and clouds causes to loose the guide star, PHD or something causes the mount to shift/drift and i am losing the framed target. I must then first recenter my target, prior to continuing  the image session. Polar aligment is about one arc-minute.  I have tried different setting regarding star mass detection, even disabling it. I have increased the size of the search region, but none of this setting seem to help. Am i missing something? does anybody have an idea what would be the cause of this problem?

CS Haakon
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Moorefam 3.58
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Does the mount drift by the same amount if not guiding at all?
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HRasmussen 0.90
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No. I can take a 30 second exposure without guiding. Perhaps even a minute.
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CCDMike 5.02
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·  1 like
I'm not sure but with clouds/without guidestar phd can't guide, right? Maybe it tries to find a new guidestar and this causes your "shift/drift".
This is a problem for everyone of us. I personally fight it within NINA with recenter and restore guiding.

Best
Mike
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HRasmussen 0.90
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That could be the problem. Is there any way to prohibit PHD to seek a new guide star?

CS Haakon
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ODRedwine 1.51
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·  2 likes
Turn on the trend-line.  If the trend-line is not centered on the zero line you are over correcting or under correcting.  If you are over or under correcting the target will walk away from the center of the field even if you have 0.5As guidance.

 The best cure for either under or over correcting is to use a smaller minimum move, and/or a shorter exposure interval.

CS
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HRasmussen 0.90
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Thanks David,

i will try that.

CS Haakon
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