Re: EXOS 2 / PMC-Eight not keeping track of tracking during slews #EXOS2



Use / try  ASCOM 6.4

The 6.5 version is giving some inconsistent results.

Let us know if it fixes things

From: <> on behalf of Pete Armstrong <PeterArmstrong@...>
Sent: Tuesday, August 4, 2020 10:43:49 AM
To: <>
Subject: [ESPMC-Eight] EXOS 2 / PMC-Eight not keeping track of tracking during slews #EXOS2
Hello, My first time in this forum.
While getting set up with POTH connections to multiple apps (TheSky6, PHD 2, and SharpCap) I notice a strange behavior during even very short slews in both Dec and RA.
I assume that since the EXOS 2 has no encoders to report scope position, the polling must use stepper counts to report position.  When I do a short jog in either Dec or RA and then an opposite jog to return, the scope reports a substantial error in RA.  It is always an arc-minute or more to the East.  My thinking is that either the mount is not tracking during the slew, or the appropriate motor counts (slew plus tracking) are not accounted for.  This also occurs whenever I slew to another target and then back.  Fortunately, the manual guide tool (pulse guide) in PHD 2 doesn't exhibit this error, so it only happens for actual slew commands.

This can't have anything to do with mount gearing errors or backlash since there are no encoders to detect those.  I haven't yet verified this behavior with actual images, and so maybe it is just a mount reporting issue.

I am using the 9T_17a_EXOS2.eeprom firmware from the 2020-JUNE-08 FIRMWARE RELEASE, ASCOM Platform, and ES_PMC8 Setup_20190107AnyCPU.exe driver.

Any Thoughts?

Thanks, Pete

Mounts:       ES PMC-Eight G11 - upgraded with OPWB on both RA and DEC
                     EXOS-2 GT PMC-EIGHT
Scopes:       Televue NP127IS with HSM20 and focuser boss II - Questar field model 3.5 - Takahashi FC76 classic MC Starbase Tokyo edition - Takahashi FOA60Q - Zeiss telementor - Lomo Astele 150mm
Cameras:     ZWO ASI071 PRO
                     ZWO ASI 290
Misc:            Televue 0.8 X  Focal Reducer - ZWO ASIAIR-PRO
Eyepieces:  Pentax - Masuyama - Televue - Takahashi - Vixen
Software:     Starry night PRO 8  - Nebulosity - Topaz studio - Sharp cap

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