Calibration fails

[Dominique DANIEL]

HI, I try several times with different values of RA and DEC autoguider rates (from 50 to 80). Each times calibration fails, because star was not moving enough. The mount seems to be OK. It's the first time that it happens.

here is the log https://openphdguiding.org/logs/dl/PHD2_logs_Sz98.zip 

Your analyse will be welcome!

Best, Dominique

Mount: CGX

Payload 22 kg

[bw_m...@earthlink.net]

Well, something has gone wrong either with the mount or with something else that is making it nearly impossible for PHD2 to move the mount in Dec.  Here’s an example (Dec in green):

 

 

The scope might be way out of balance in Dec or you might have a cable routing problem.  If not those kinds of things, I would say something has gone wrong in the Dec drive system.  You can use the Star-cross Test or the Manual Guide tool to investigate.  You can’t fool around with the mount guide speeds though – set them at an appropriate level (nothing below 0.5x sidereal) and leave them alone.  Set them properly in the mount driver/firmware, then use the PHD2 ‘Advanced’ button on the Guiding tab of Advanced Settings to restore the correct calibration step-size.  You’ve got a hardware problem here, nothing to do with the PHD2 calibration process.  While you’re working through this, be sure to manually clear the Dec backlash before starting the calibration.  While looping guide cam exposures, press the ‘Up’ button on the hand-controller until you can clearly see the stars moving in the display.  Then start the calibration.

 

Good luck,

Bruce

--
You received this message because you are subscribed to the Google Groups "Open PHD Guiding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to open-phd-guidi...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/fd30456a-79e7-44f9-bd4f-c8bc93b2e81bn%40googlegroups.com.

[Dominique DANIEL]

Thanks a lot Bruce. 

I will do that. But I can't explain there is no problem when aligning stars "manually": the mount slew correctly in all directions, even at very low speed. I do that very accurately, and quickly. Of course, at daylight I will check the mount.

Best, Dominique

[bw_m...@earthlink.net]

You’re not manually moving the mount at guide speed, but that’s what the Manual Guide tool in PHD2 will do.  At the guide speed you’re using, it would take you 8 minutes to move the mount by 1 degree. To minimize the number of variables, re-position the scope to 4.6 hours east of the central meridian at Dec = 16 and run the test there.

To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/00cacea4-ad1d-4243-931f-70f4185accb5n%40googlegroups.com.

[Dominique DANIEL]

Interesting. I will do that.

In the mean time,  I've updated the mount (no change).. and suppress the small DEC backlash. Calibration now succeed but with poor quality. I retry with PEC inactive.  Then PHD2 calibration, PEC Train, PHD2 recalibration (with New PEC). calibration and guidind remain not good enough (RMS 1.3" where I expect 0.6").

You received this message because you are subscribed to a topic in the Google Groups "Open PHD Guiding" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/open-phd-guiding/P-TkN1bZD4E/unsubscribe.
To unsubscribe from this group and all its topics, send an email to open-phd-guidi...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/open-phd-guiding/001801d904d6%24f9e3ab20%24edab0160%24%40earthlink.net.