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On 12/14/2020 3:31 PM, Brian Valente wrote:
>? >>> the PHD2 frequency analysis of a GUIDED
> session shows an 0.8" residual error at the bearing frequency of 76s.
>
> haha - well you keep asking about PE errors :)

OK.? When I ask about PE I am asking about PERIODIC ERROR.? I define
periodic error as an error in pointing that is periodic.? To me, PE
means Periodic Error.? PEC means Periodic Error Correction.? Same page
so far?

I have been asking about PE (NOT PEC) in a PHD2 log of a GUIDED session.
? I am asking if the displayed amplitude of the periodic error in the
viewer is the residual pointing error after guiding has been applied.? I
think it is but I am not sure.? Hence the question.? See below as well.

>? >>>I assume that represents the remaining RMS amplitude of the guide star
> error after guiding corrections have been applied?
>
> that answer depends on how you arrived at that value, IUf you used PHD
> Log viewer and you selected analyze RAW RA, then it's an estimate of the
> total RMS of that error, not the residual.

Let me try it again.? My question referred to the magnitude of the
periodic error at any given frequency as displayed in the PHD2 log
viewer.? I right click in the log and select "analyze selected frames".
? I then select the "frequency analysis" tab.? My question..... is the
displayed magnitude of any given signal in the frequency analysis screen
the residual error after guiding has been applied?? I think it is.? If
so, I'm seeing about 0.8" at the 76s worm bearing rep rate and I can
live with that if I have to..... for now.? My seeing is usually worse
than that so it swamps that signal.

But if my understanding is correct and I can not remove that 76s signal
with G2 PEC or PEMPro PEC because it is not phase locked to the worm
rotation then at some point I need to address it mechanically if I want
to improve the RA tracking.? Correct?? If so, my options are limited to
replacing the worm bearings or adjusting the worm blocks.? Correct?

That is what I have been trying to ask and I don't know how to be any
more precise.? I think I understand things but I could be wrong.

And yes I know this would be SO much easier if I could go out and grab
an unguided session but that isn't in the card right now.? Forecast is
cloudy for the next 5 days at a minimum.? Maybe I should have taken up
radio astronomy?? ;)

Paul

--
Paul Goelz
Rochester Hills, MI? USA
pgoelz@...