Mount advice?

[Paul Wilson]

https://openphdguiding.org/logs/dl/PHD2_logs_6cVg.zip

Yes, unfortunately here I am with another log.  I looked at this one and showed it to an AI.  The AI seems to think that PHD was doing everything it could to help the mount track the guide star, but the mount, a brand new CEM70 was full of backlash.

I tried in this session to do what I know how to do.  I re-calibrated guide scope after mount was re-polar aligned at the remote pier.  The error had been large, over 2 degrees.  It was back now at under 2 minutes (I will check PA again tonight),  Then I used the guiding assistant and applied its suggestions.  I lengthened guiding exposures to 3 seconds.  I raised and lowered the DEC aggressiveness and tried both north and south orientations.  Didn't seem to help.  

AI suggests that the gear in my new mount may be sticking.  But since the guiding assistant again said that my guide scope needed better focusing, I bought a better guide scope with a helical focuser instead of pushing the guide cam back and forth.  I'm waiting for them to install it.

AIs are sometimes wrong, so I thought I should submit this log and trying a new guide scope before contacting iOptron.

[Brian Valente]

Paul

Can you post some pictures of your setup from different angles

>>>Then I used the guiding assistant and applied its suggestions.

Did you review the guiding assistant results? Without any guide pulse exposures, you have huge spikes in Dec (red line below) and fairly large spikes in RA as well. You aren't going to get anywhere when the mount is performing like this. 

>>>  I lengthened guiding exposures to 3 seconds. 

Things improved here considerably so i recommend (as always) to start your guiding sessions with a guiding assistant run, especially as you are troubleshooting your setup.

>>>AIs are sometimes wrong, so I thought I should submit this log and trying a new guide scope before contacting iOptron.

AIs are usually wrong when it comes to this kind of nuanced analysis. 

To net it out, i don't think you really have any guiding-related issues, you still seem to be working on commissioning your mount. If possible, I suggest bringing it home and working on it in your backyard. Remote is creating a lot of overhead and uncertainty for you and increasing the required effort.

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Brian 

Brian Valente

astronomy portfolio https://www.astrobin.com/users/bvalente/ 

[Paul Wilson]

I did forget about the pulse images. I will get those.  I agree that it is very unlikely that PHD is doing anything amiss.  

I can ask the staff for photos, they are the “under” staffed.

I have never torn down a mount so it wouldn’t be my first choice. Perhaps they would exchange it.  

There could also be something wrong with the pier it sits on.  

Thanks for helping me out

Paul S. Wilson

Continental Airlines

Capt.  IAH

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[Michael Waring]

Hi Paul

I believe you have misunderstood what Brian said.

Brian said " Did you review the guiding assistant results? Without any guide pulse exposures, you have huge spikes in Dec "

You said  "I did forget about the pulse images. I will get those"

Brian means that you can see huge Dec spikes in the Guide Assistant run.

Depite RA and Dec guide pulses being deliberately switched off in a Guide Assistant run.

So there are no "pulse images" for you to get.

Michael

Wiltshire UK

[Ralph Kimball]

Hi Guys, this topic caught my eye because I recently solved a guiding problem on my CEM70 with the help from “ip” at Starfront. Here’s what I posted on the Starfront Discord this morning: BIG shout out to ip! I've had a tricky intermittent problem with my rig where it uses the J2000 epoch for positioning and does not automatically convert to the JNOW epoch. Last night in desperation I logged in to the NINA track and described the situation. TWO MINUTES later ip responded and asked me to send a test image. When I did, he said that ASTAP needed a better focused image to compute the conversion from J2000 to JNOW. When I inserted AutoFocus at the very start of the session, IT WORKED! While I now understand the issue, I went down way too many rabbit holes on my own trying to figure this out. Didn't need to do a deep dive with iOptron Commander. Arghh!

[Paul Wilson]

Yes I figured that out last night. I am not new to PhD but I am new to having to really get into it to get mounts at remote location to guide well.  I made a number of adjustments last night that seemed to help. 

Today a new guide scope with helical focusing which will require another new PhD profile and calibration.  

Also I am relieved to read that the CEM70 can be manually user adjusted more readily than my old EQ6 should that become necessary.  

I upped the slew speed from .50 to .75 to .90 last night and it helped.  I also didn’t have “use multiple stars” box checked which might help.

Paul S. Wilson

Continental Airlines

Capt.  IAH

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