Re: Guiding a mach1 - and pec?

Eric Claeys

I tried Roland's suggestion to check my Mach 1's tracking accuracy.

All runs were with a C11 with mirrors locked and the scope pointing near the zenith.

Camera was rotated 0 degrees (per a plate solve).

With PEM off, the results look pretty bad: +/1 about 6" in RA.

With PEM on, the results are significantly WORSE.  I ran PEMPro earlier (pointing near the meridian and equator, per the instructions).

All screenshots are in the "EricC" folder, called "PE and PEMPro":

  • PE run - 1 PEM off, APPC settings: shows APPC and 3D view, prior to starting the PE run per Roland's instructions.
  • PE run - 2 PEM off - PHP graph: PHP graph with PEM turned off.  Roughly 13 minutes.  DEC was doing ok until about half way then went down.
  • PE run - 3 PEM on - PHP graph: the peaks go to about 12" (I left the scale the same as in the prior run).

Screenshots of my PEMPro runs, before and after sending to the mount:

  • PEMPro - 1 Acquire Data, 3 cycles: shot of the "Acquire Data" tab.
  • PEMPro - 2 Analyze - Create PEC Curve: after clicking on "Create PE Curve" in the "Analyze" tab, and changing the Drift Fitting to get the lowest RMS error, then checking all Frequencies below 16 that had at least 0.05 amplitude.  Periodic error is +4.7/-3.6 which is outside the +/-3.5 advertised.
  • PEMPro - 3 AP Raw PE: the curve downloaded to the mount.
  • the next 3 shots (PEMPro - 4, 5, and 6) are the same but with PEC on (and NOT loaded to the mount).

Given that the new PEMPro curve made things worse, I assume I did something wrong (although I followed Roland's instructions).  RA goes left and right in the pictures (if I take a picture when the mount is parked the streaks go right and left).

Any ideas?


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