Re: AP1600 autoguiding gone bad

Ray Gralak

Hi Greg,

Which version of the ASCOM driver are you using? Since you are using a GTOCP3 you might want to stick with one of the older ASCOM drivers like 5.21.01.

New rate commands were added in the 5.30.xx versions for the Mach 2 and newer GTOCP4 firmware, so maybe one of those rate tables is getting used.

Here is the link to AP V2 v5.21.0:

-Ray Gralak
Author of PEMPro
Author of APCC (Astro-Physics Command Center):
Author of Astro-Physics V2 ASCOM Driver:

-----Original Message-----
From: [] On Behalf Of Greg Bradley via
Sent: Saturday, January 9, 2021 3:31 PM
Subject: [ap-gto] AP1600 autoguiding gone bad

I have a usually reliable AP1600 mount.
It is slewing fine but autoguiding suddenly went wild a little while ago.
So normally I get very small guide errors .2 to .6 arc sec
guide errors. They suddenly went to 15-20.
I couldn’t get it to callibrate either using relays.

I switched to pulse guiding and I could callibrate.

But guiding is still wild. I tried various settings
for the guiding.

I pulled apart the electronics box and inside it looks lile

I noticed in the driver you can set the guide rate and it was set at 1 so I reduced that to .5 and I can set it lower. I
will disconnect the hand controller
tonight in case that is having an effect.

Any suggestions?

I am using SkyX, ascom mount and the AP driver. Its an AP cp3 electronics.

I am able to do plate solving, polar alignment using TPoint so go to’s are working.



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