HEQ5 PEC problem

[astrosatch]

Greetings!

I have problem with pec, because  apparently it isn't working.I have skywatcher 200p mounted and reasonably balanced. Polar alignment is pretty accurate.there is no drift in declination axis for at least 5min. I trained PEC and the star was always in centre, but after it finished and i set tracking PEC + sidereal and checked the situation there seems to be almost no correction at all.The star drift left and right along RA axis almost exactly as there is no PEC.Maybe drift is  slightly narower than without PEC, but than again only slightly.I was listening the motors for correction sound and had a feeling  that the mount made in PEC mode fewer corrections than I made in training mode.It's like the mount is skipping corrections or not making the right ones.Or maybe It's just my bad observation. Does anybody know what could be the problem here, and what is your experience with pec?

thanks

[jambouk]

Did you make many corrections when doing the PEC learning, you haven't said. Might the corrections you taught it actually errors in polar alignment and now you've still got those errors and the mount is also trying to add in spurious corrections for that as well as simply playing the uncorrected Periodic errors as well?

I've not tried to do it yet, but i'd have though the best time to do PEC learning would be during a guided run; otherwise i suspect some (maybe most) of the errors may just be down to inaccurate polar alignment.

James

[jambouk]

PEC training using a guidescope is only an option for the AZEQ6 and EQ8, sorry.

James

[dph1nm]

i set tracking PEC + sidereal and checked the situation there seems to be almost no correction at all

 You were lucky! When I tried this on my HEQ5 the other week PEC made the tracking much worse. I don't think I will bother again.

NigelM

[chrisshillito]

PEC training using a guidescope is only an option for the AZEQ6 and EQ8, sorry.

James

Its an option if you use EQMOD.

Chris.

[1parsec]

 Does anybody know what could be the problem here, and what is your experience with pec?

Hi,

For the PEC  correction functiuon to work the periodic error of the mount needs to show a repeatable 'overlapping' pattern.

In my HEQ5 the motor gearing and mainly the transfer gear added a large error to the overall periodic error.

In fact the error was no longer at all periodic and the PEC function was usless on my mount too.

See post 22  on his thread  http://stargazerslounge.com/topic/189089-heq5-standard-ratio-947-belt-mod/page-2

The screen grab show the non-overlapping pec curves.  You could record a PEC training for one cycle of the worm and the periodic errors would quite different the next.

The solution was to remove the gearing and fit my belt mod kit.

I would download and run PecPrep to help analyse what your periodic error looks like, where the errors are and take it from there.

Dave.