Sponsored By:

Subject: Re: More on Drive Rate
From: Bob Higgins
Reply To: mapug@shore.net
Date: Tue May 30 05:58:15 1995

A few weeks ago, the issue of open loop drive rate surfaced. This weekend I spent some time optimizing my 10" LX200 setup (observatory, on a wedge, version 2.5) for unguided CCD imaging. What I found after hours of drift aligning, was that to get reasonable unguided images required the drive rate to be set at 59.6 Hz manual rate for a siderial subject! Something is immensely wrong here. It is unlikely that the quartz oscillator is off by 8000 ppM; quartz oscillators won't oscillate that far off of their normal resonance. To be this far off, something has to be wrong with the software or the mechanical gear ratio.

What good is having a highly stable quartz rate if it is so far off it can't be used? My understanding is that the PEC can only be trained from within this mode (the PEC was on during this optimization). It is possible that the PEC training firmware is faulty and that training alters the steady state rate. I have not heard any comments from Meade on this matter. Is Scott listening? We need some input.

Regards, Bob Higgins