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The great G11 windup
I have been wondering why I sometimes get horribly trailed stars in the 30 sec poining exposures. I have been playing heaps with PEMPro overnight and found that although I have low PE once I got a nice PEC curve loaded it's about 4 arcs p-p with an ovision worm and about 8 without PEC. However several times I started a PEMPro run straight after slewing to a bright star in the finderscope using teh handpad at visual slew rates (no a goto) what i saw was a huge (but smooth) rise then fall of about 30 arcs over a period of about one and a half minutes before it settled into a flatline (almost). This is why after slewing for a pointing update it often gave huge streaks in the 30 sec image and failed to solve. After this period everything is perfect and tracking and image taking is fine.
I still don't know the reason for this windup period. Perhaps it is backlash in the RA or an imbalance?
This behaviour was casuing me grief when I first started trying single images from the web interface. The sequence was like this. Select a single target single image, 60 sec only as it wasn't working I didn't want to waste time. Start, slew to RA Dec, take pointing image that failed due to streaking, slew to offset, fail again, take image without pointing update, object not centered, also as the image was moving so fast the autoguider would fail as it was often falling outside the box and error was to high. Then the tracking stops as the run is finished so the mount never wound up fully. Try the same object again it had to slew again, etc etc
I am going to next time go against advice and try constant approach slewing and try balance combinations. I don't know if it is to do with the load which is only one 10" Meade OTA at present. Perhaps the lubricant is to thick?
BTW if i do a multi image series it all works fine as the mount is left to track and winds up fine so the images are perfect.
This isn't an ACP issue, just comments about how ACP and MY gemini G11 had been fighting in case others are having the same issues and are a bit lost.
I will try next clear night to do a run starting straight after a slew and post a graph.
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I did finally solve this issue. After a slew when doing say a pointing run many of the images had bad trailing. The cause was a stickyness in the RA bearing, caused by those horrible plastic clutch washer/plates.
Because the plates slipped so badly you needed to tighten the clutch knob so tightly to make the clutch engage the bearing had a very high static friction, for the first 20 -30 seconds all that happened is the worm built up tension trying to move the mount in RA but failed.Once the force was enough to overcome the static friction it started to move the dynamic friction was low enough so the mount hen moved smoothly. The Losmandy answer was to sell you special cluch knobs with extra handles so you could do the bearing up tighter!!! Replace the clutch material and it feels like a new mount.
If you want an example of this try the difference between an Obsession telescope and how easily it moves to a badldly designed home made. The bad mount sticks as you apply pressure then moves to far and is horrible to use.
I have replaced the plastic disc's with 1mm thick cork sheet disc instead. Now I only need a low amount of tension on the clutch knob and the clutch engages perfecly. The bearing is not under huge tension so the worm is able to start it turning much more easily and the streaking in the first 20-30 seconds goes away!