Re: My brand new AP1100 - play in both RA and DEC axis


As recommended by Roland, I was able to eliminate the worm play on both axes by adjusting the backstop. I also had a talk with Howard to clarify some details re. the DEC axis and greasing. Thank you both very much for the assistance.


On the RA axis I only needed to loosen the two screws and to apply the slightest pressure on the lever holder for it to move in position. After tightening the screws, the play was gone.


On the DEC axis I had to repeat the process four times before I could correct the play. Only after applying some pressure on the lever holder and a lot of wiggling was I able to bring it into the right position. Interestingly, in the beginning, the lever itself refused to move the complete 180° to release the worm. In the open position, it looked like this:




After that, I loaded the mount with a telescope, balanced it and slewed it all around the sky. Everything seems to be normal now. Could not yet do a test-run under the stars.  


Just for the record, the mount is brand new, it left Astro-Physics on August 26-th and I am the first one to open the boxes.


Kind Regards,




Von: <> Im Auftrag von Roland Christen via
Gesendet: Dienstag, 14. September 2021 21:41
Cc: howard@...
Betreff: Re: [ap-gto] My brand new AP1100 - play in both RA and DEC axis



You did not get this mount directly from us at Astro-Physics. We shipped this mount in February, and we never ship things loosely in the box, so whoever shipped it to you did not pack it correctly.


The play that you see on the worm wheel is not normal. It appears that the worm is not fully engaged with the worm wheel. If you open the side cover you will see a lever. It is almost certain that the previous person loosened the two screws on the backstop adjustment, which allows the worm to come out of mesh. Please read the instructions in the manual for adjusting the backstop on our spring loaded gearbox.


If you need more help, please consult with Howard at AP.


Roland Christen

Astro-Physics Inc.


-----Original Message-----
From: Horia <ATM@...>
Sent: Tue, Sep 14, 2021 1:13 pm
Subject: [ap-gto] My brand new AP1100 - play in both RA and DEC axis

Today I got the chance to take my  AP1100 mount out of the wrappings and set it up on the pier.


  1. The altitude bar was completely loose inside the RA-axis box and managed to produce some deep scars on the coating of the side walls of the polar fork. I would suggest to put it in a bubble wrap before dropping it in there.


  1. Both the RA and the DEC axis have some (a lot of) play between the worm and the worm wheel.  An iPhone movie showing a close up of the worm wheel on the DEC axis:



I do not think this is as expected. How do I get rid of it?


Kind regards,



Roland Christen

Join to automatically receive all group messages.