Old 06-03-2016, 10:26 PM
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barx1963 (Malcolm)
Bright the hawk's flight

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Location: Colac vic
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Guiding query

I have a query about my guiding behaviour. When I start an image, my guiding graph start off with the Dec (red line) moving a lot for a few seconds, then it corrects and starts guiding quite happily. I have attached a screenshot showing this. The second shot shows a reasonable graph a while later. Both of these are during an imaging run of Eta Carina.
Gear used is

Mount Orion Atlas AZ/EQ G
Guidescope Orion ST80
Guide camera Orion SSAG Pro ( I believe this is a rebadged QHY5?)
Guiding with PHD 2 version 2.6

It almost feels like despite calibrating, it wants to check it again and moves whe mount a bit more before settling down. The images in the main scope appear OK. It is just annoying that it seems to happen each time.

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Old 06-03-2016, 10:39 PM
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Atmos (Colin)
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On the surface of it, it looks like backlash where it just takes a few guide pulses for it to over come that.
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Old 06-03-2016, 10:49 PM
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barx1963 (Malcolm)
Bright the hawk's flight

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That was my suspicion, but didn't know enough to be sure. I will have to read up a bit more to learn how to minimise this.

Thanks Colin!!

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Old 06-03-2016, 11:48 PM
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billdan (Bill)
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That is what usually happens with my EQ6 Malcolm, I wait about 2 minutes for the trend lines to flatten before I start imaging. As to why it does it I don't know, even if I clear the graph after 10 or more minutes it will do the same thing. Must be quirk in PHD2 rather than in the mount.

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Old 06-03-2016, 11:56 PM
kens (Ken)
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Looks like it could be backlash.
But post the full guide log - screen shots don't tell enough.
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Old 07-03-2016, 07:46 AM
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jenchris (Jennifer)
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Phd learns over the first few iterations what the proportions are for dec alt.
Hysteresis learns the bias and applies it.
Raising hysteresis will adjust the learning cycles.
Increasing the exposure might settle the jagged lines. You appear to be chasing the seeing
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