My AP1600AE has developed a habit of rocking back and forth in RA while guiding #Absolute_Encoders


steven ho
 

Both Encoder lights are blue and the voltage is steady at 13.5. 

Attached is an example of a 60 second exposure during the rocking.

An ideas?

Thanks!!
Steve


ap@CaptivePhotons.com
 

Does it do it if you turn off guiding?   How about during guide assistant when there would be no PHD2 inputs to the mount? 


steven ho
 

Yes the same behavior happens when only tracking.

Steve


 

Hi Steven

is that exposure with tracking off? If so, have you analyzed it to determine the rocking error?

are you using a model?

On Sun, Jul 3, 2022 at 7:43 PM steven ho <StevenHoffman53@...> wrote:
Both Encoder lights are blue and the voltage is steady at 13.5. 

Attached is an example of a 60 second exposure during the rocking.

An ideas?

Thanks!!
Steve




steven ho
 

The expossure is with tracking ONLY PHD2 was not used, I misspoke when creating the subject line. It should read "while tracking".

The streaked stars are a rusult of the mount rocking back and forth. It's clearly visible. The dangling wires are easy to see rocking back and forth.

Thanks
Steve


steven ho
 

It doesn't always happen. It seems to occur at certain points in the sky. It always happens after a slew.  If it doesn't happen after a slew then it doesn't happen at all.
I parked the scope for the night. Next time I will turn the AE's off and test.

Steve


Mike Pigney
 

My Mach2 shows a similar behavior.

I found that changing the counterweight position to offset the balance cancels it out.

Mike 


Brent Boshart
 

This may be an issue with the encoders causing an oscillation. The AP staff can help you adjust the dampening parameters.  


Mike Hanson
 

Steven,

I have contacted you privately for troubleshoot.

Regards,
Mike Hanson


steven ho
 

Thanks very much Mike!!

I hope everyone enjoys the 4th of July festivities.

Thanks!!
Steve


Roland Christen
 

We have new software that can be downloaded for both the CP4 and CP5 that addresses some of these issues. The problem is that for some heavy loads the mount needs more internal dampening in the control loop than what was originally set at the factory. It's a matter of how much moment of inertia the mount sees on the two axes. Very high inertia can lead to instability. And it isn't just weight, rather it is weight at a distance from the axis. Therefore a 50lb scope that is 20 inches in diameter will have much higher inertia that a 50lb scope with 10" diameter.

Tomorrow when everyone is back here in the office I will have Mike contact those who have seen this effect and we can have you run a few simple tests to see what software settings you have in your controllers. Then we can make some recommendations which will fix this issue for you.

Rolando

-----Original Message-----
From: Mike Pigney via groups.io <mpigney@...>
To: main@ap-gto.groups.io
Sent: Mon, Jul 4, 2022 7:09 am
Subject: Re: [ap-gto] My AP1600AE has developed a habit of rocking back and forth in RA while guiding #Absolute_Encoders

My Mach2 shows a similar behavior.

I found that changing the counterweight position to offset the balance cancels it out.

Mike 

--
Roland Christen
Astro-Physics


steven ho
 

Mike took care of me Rolando, thanks!!

Steve