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iOptron CEM 40 guide rate

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#1 muthunag

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Posted 03 March 2021 - 10:53 PM

Hello CN
   I have an Ioptron CEM 40, running the latest firmware (v5. 7.5, Sept 2020) and the most recent stable ASCOM Platform & drivers. I guide using PHD 2 and use APT for acquisition. The last couple of times I notice PHD 2 displays an error message that says that the calibration has to be redone as the mount guide rate has changed since calibration was performed. I calibrate everytime I set up.

   But after seeing this error, I checked the guide rate setting in Ioptron commander under mount settings and sure enough my mount's guiding rate has been changed from my default of 0.75 for RA and 0.75 for DEC to 0.5 on both axis.
   The problem is that with a rate of 0.5, I am unable to complete my guide calibration. It takes forever to move the guide stat the necessary steps to calibrate at a rate of 0.5. if I manually reset it back to 0.75, and press apply settings, nothing happens. It appears the settings are applied but if I close the settings panel and reopen mount settings, the guide rate has besn reset to 0.5.
  I have looked at all the settings in PHD2 and APT to figure out if there is anything else that is over riding the guide rate setting and there are no other ways for me as a user to sepcify this information except on tbe Ioptron commander software.

   This has been very frustrating to deal with as you can imagine being out in the field and having set up all equipment in tbe dark and in the cold but running into this error with no apparent solution. I can't think of any changes to my software or my drivers and my prior to this, the same versions do the software and firmwares gave me no such issues. 
   Please help. Has anyone else seen something similar?

 

Thank you,



#2 NoDarkSkies

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Posted 04 March 2021 - 01:38 AM

PHD2 said to put my mount at .10 on both running Guiding Assistant.
Did you run Guiding Assistant?
YouTube Video


Edited by NoDarkSkies, 04 March 2021 - 01:43 AM.


#3 muthunag

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Posted 04 March 2021 - 05:39 AM

Thank you! I will run guiding assistant and see if that fixes it! I think I ran it once a while ago, when I first got PHD2 set up, but certainly i have changed my guidescope and my imaging scope since then and it would not be bad idea to run it again.

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#4 jonnybravo0311

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Posted 04 March 2021 - 08:03 AM

FYI, the latest firmware for the CEM40 is from February of 2021. See here: https://www.ioptron....cles.asp?ID=318

 

As for guiding speed, I have mine running at 0.5x. Guiding assistant has never given me any advice to change it.

 

Now, if only the command from NINA to do a meridian flip would actually work... 


Edited by jonnybravo0311, 04 March 2021 - 08:05 AM.

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#5 muthunag

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Posted 04 March 2021 - 08:09 AM

FYI, the latest firmware for the CEM40 is from February of 2021. See here: https://www.ioptron....cles.asp?ID=318

As for guiding speed, I have mine running at 0.5x. Guiding assistant has never given me any advice to change it.

Now, if only the command from NINA to do a meridian flip would actually work...

That's right! I really hope upgrading the firmware fixes the issue. Thank you!!

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#6 michael8554

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Posted 04 March 2021 - 08:11 AM

PHD2 said to put my mount at .10 on both running Guiding Assistant.
Did you run Guiding Assistant?
YouTube Video

I suspect that's a Minimum Move setting, guide rate doesn't show in a Guide Assistant run.

 

0.5 is a valid guide rate that should Calibrate in PHD2, if you have the correct Focal Length and pixel size entered - a common mistake is to enter the aperture eg 60mm,  instead of the focal length eg 200mm.

 

That would cause tiny Cal steps.

 

Post a PHD2 GuideLog that includes a Calibration, or open the GuideLog in NotePad and look for the guide rate etc in the info at the start of the Cal entry.


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#7 jonnybravo0311

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Posted 04 March 2021 - 08:14 AM

That's right! I really hope upgrading the firmware fixes the issue. Thank you!!

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One other tip... the new firmware and iOptron Commander software has the ability to record the PEC of your mount. It does NOT play nicely with PHD2, so don't bother running it. Let PHD2 manage things. You can try the PPEC algorithm in PHD2 if you really want; however, I've found the hysteresis algorithm works just fine, too. Run the guiding assistant for 10 minutes or so. Implement its recommendations. Oh, and if you haven't yet, try the multi-star guiding. On my setup, I typically get 0.6" - 0.8" total error. Not the best, but certainly good enough for my normal seeing and scope/camera resolution.


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#8 muthunag

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Posted 04 March 2021 - 08:18 AM

One other tip... the new firmware and iOptron Commander software has the ability to record the PEC of your mount. It does NOT play nicely with PHD2, so don't bother running it. Let PHD2 manage things. You can try the PPEC algorithm in PHD2 if you really want; however, I've found the hysteresis algorithm works just fine, too. Run the guiding assistant for 10 minutes or so. Implement its recommendations. Oh, and if you haven't yet, try the multi-star guiding. On my setup, I typically get 0.6" - 0.8" total error. Not the best, but certainly good enough for my normal seeing and scope/camera resolution.

I am loving multistar guiding. It has tremendously improved my total error. After reading about PEC conflicts with PHD 2, I didn't record my PEC. I have left it at standard default algorithms for both RA and Dec for now. I do plan on experimenting with PPEC algorithm on PHD 2.

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#9 rgsalinger

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Posted 04 March 2021 - 05:16 PM

"The problem is that with a rate of 0.5, I am unable to complete my guide calibration. It takes forever to move the guide stat the necessary steps to calibrate at a rate of 0.5."

 

This is normally fixed by increasing the step size rather than changing the guide rate. The guide star needs to be moved enough so that the pixels per arc second can be accurately calculated. If the step size is small then it will take a lot of steps for the mount to move far enough to make PHD happy. 

 

I would not expect that .75 will give you any problems, but it's not what iOptron recommends. Sounds like the latest driver is trying to enforce that rule. 

 

If you keep the guide scope and guide camera set up on the OTA and use ASCOM guiding you could avoid having to recalibrate each night. If that's possible for you, you might want to try it and see how it goes.

 

Rgrds-Ross


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#10 muthunag

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Posted 05 March 2021 - 07:19 AM

"The problem is that with a rate of 0.5, I am unable to complete my guide calibration. It takes forever to move the guide stat the necessary steps to calibrate at a rate of 0.5."

This is normally fixed by increasing the step size rather than changing the guide rate. The guide star needs to be moved enough so that the pixels per arc second can be accurately calculated. If the step size is small then it will take a lot of steps for the mount to move far enough to make PHD happy.

I would not expect that .75 will give you any problems, but it's not what iOptron recommends. Sounds like the latest driver is trying to enforce that rule.

If you keep the guide scope and guide camera set up on the OTA and use ASCOM guiding you could avoid having to recalibrate each night. If that's possible for you, you might want to try it and see how it goes.

Rgrds-Ross

I have to set up and tear down every session as I travel about 20 mins to a relatively darker site and my own backyard gives me a poor view of the night sky

But, I have good news! I upgraded my mount firmware to the more recent January 2021 version and also noticed that for whatever reason windows was running Ioptron commander as administrator, while all the other software didn't have that privilege

I made sure that I disabled that option and it all worked without a glitch yesterday! I spent about 3 hours on Cone nebula before dew & moon cut my night short. So excited to process the data!

Thank you all at CN for helping me with this issue.. this community here is priceless.




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#11 NoDarkSkies

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Posted 05 March 2021 - 10:11 PM

Time for me to update mine now, thanks for the update.




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