On Sun, Mar 2, 2025 at 11:25 PM, John Kmetz wrote:
Dale,
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This seems bizarre behavior. Dec (which should be in red) typically will drift in one direction if PA is off. If seeing is bad it should vary randomly. Having a repeating pattern I think is something software other than hardware as the Dec motor should only be rotating back and forth as corrections are needed.
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Some random ideas:
-Are RA and Dec cables reversed (probably not)?
-Are you dithering after every frame and is the dither large?
-Have you checked TVC in the hand controller, perhaps too large a value?
-Dec MinMo seems large - I'm seeing changing values from 0.2 to 0.35
-57# on an GM811 seems, like a lot. If a G11 has 60# payload, the 811 is less, I think. Are your counterweights all at the bottom of the CW shaft? Perhaps too much moment-arm the mount can't handle.
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All I could think of for now.
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Good luck.
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John
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Losmandy G11G2 on pier; refurbed Losmandy G11 with OnStep controller; SkyShed design roll-off observatory; ZWO ASI2600MM-P; ZWO ASI071MC; Sky-Watcher Esprit 100 ED with field flattener; Celestron C925 Edge HD with 0.7XFR, William Optics Zenithstar 61 APO; PHD2, NINA, Sequence Generator Pro and PixInsight user
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John K,?
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Good call on the TVC setting which AFAIK should always be set to zero.?
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The OP's actual payload is only 28lbs. in the saddle not 57lbs which is the TOTAL of his saddle payload plus counterweights.? ??
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Something nobody has mentioned yet is that we don't know if the mount is properly balanced on both axes or not.? As you know it's not just the RA axis payload in the saddle, the weight balanced by the counterweights, but also the balance of the DEC axis, which runs along the axis of the optical tube, that requires good balance.? If the DEC axis is not balanced and there is some backlash the same tooth to tooth bounce can happen on the DEC axis worm and worm gear.?
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The questions in my first post may still hold the answers once the OP posts the answers.? ? ? ?
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Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
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Chip Louie