I think I've tried everything. Does my mount need a repair?

[Gary Barr]

Thanks for any help anyone can give me. I have been fighting not being able to get my total error <1.00 RMS.  I have an Orion Atlas Pro AZ/EQ-G mount.  It is around 7 years old.

I am constantly having issues not being able to achieve low total error rates. Last night, I finally thought I had it tracking real well.  Around midnight, I was tracking at .45-.55 total RMS.  I went to bed to let SGPro do it's thing. I woke up after 20 5 minute subs and found tracking a mess.  I had no snagged cables. I then calibrate another two more times and ran guiding assistance twice.  I did take a look at balance again on the scope. Maybe I 'm doing it all wrong.  Everything seemed perfectly balanced for dec and RA.   I did calibrate near the meridian for my first cal but the second two calibrations were done on the  M31 area. I have a 480mm scope with an OAG with .7 reducer so 336mm is plugged into the field for setup after the wizard ran.  

Does it look like my problem is with my mount?  I'm really not sure where to go from here. I'll try it all again tonight if it's clear.  

Thanks for anything, any input, any suggestions..anything.  I use Polemaster and confirm with Sharpcap my polar alignment and the scope was balanced.   I did do a manual meridian flip around 3:30AM.  Seems like nothing I do improves my tracking.

Gary Barr

Log is also here:

https://drive.google.com/file/d/1RDP92XY2YZ0DZWPh03SCzj6MXaGr-1lZ/view?usp=sharing

[Brian Valente]

Hi Gary

i'll take a stab at this

first, things overall look pretty good until trouble happens, here's your 3 hour run, removing the problem areas

then you run into these absolutely massive and instantaneous DEC excursions of nearly 100" (that's almost 2 armin)

This is immediately preceeded by lost star events in all cases. 

I noticed you have no noise reduction set up on your guidescope, so it's worth putting some on there. For lodestar probably bad pixel map is better choice for hot pixel

I suspect something that large is likely a hardware issue, so doublecheck everything is secure and tight. you might try rerouting your cables just to be safe. 

also your algorithms could use some tuning up:

enable auto backlash compensation for DEC

For RA i recommend you use PPEC, as your  484 second error constrains your guiding. 

use PPEC with period of 484.2 seconds and disable auto adjust period

Those algorithm suggestions won't address the massive excursions but should help improve your guiding overall.

It may be your jumping to a hot pixel, so bad pixel map could help here

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Brian 

Brian Valente

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[Gary Barr]

Thanks Brian,

I decided to do a hypertune on my mount and got a new EQ6R mount and it's guiding beautifully.  

I am using a PEC curve generated from EQMOD on this mount.   

Where do I" enable auto backlash compensation for DEC". Is this turned on for a default install?

Thanks so much Brian!

[Brian Valente]

Hi Gary

it's in the algorithms tab under Advanced Settings

You should do a GA run to determine how much backlash compensation to start with, but PHD's algorithm is adaptive so will adjust it to the right amount over time. 

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/3dd8052c-e601-4f67-b8d3-d8098fb2774en%40googlegroups.com.

[Gary Barr]

Thanks Brian for getting back to me so quickly.

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/CAJa45i7hL%3DxKB2iEP5LofX%2BVFQhObtJULOLUawPMmpuNTZ3aBA%40mail.gmail.com.