Hi Chris,
I am curious to see how accurate most users are getting with the raw pointing of the G11 with an accurate polar alignment via the Polemaster or equivalent, but I can give you some insight into the raw point testing we did at the factory.
At the factory, we mounted a telescope on the G11 and the EXOS 2 with a cross-hair eyepiece and we configured the mount so that we could rotate the DEC axis (which is pretty much identical to the RA axis) 360 degrees. We positioned the telescope via the clutches to center a target on the far wall of our warehouse and then zeroed the motor counts. The test was to slew the mount 360 degrees in DEC to recenter the target and record the motor counts.
We did this a total of 20 times slewing 10 times clockwise and 10 time counter-clockwise, centering the target each time around and recording the total counts. The G11 total motor counts for each axis is 4,608,000 for 360 degrees of motion. After taking the 20 measurements, I did a mean value and a standard deviation calculation and the end result was a raw pointing accuracy of < +/-4 arc-sec with a 2-sigma precision of < +/-1 arc-minute. The EXOS 2 mount is <+/-10 arc-sec with a 2-sigma precision of < +/-1 arc-minute.
So the raw pointing of both system is about +/-1 arc-minute. Add onto that the error in time for RA pointing (1 arc-minute error for 15 second time error) and any flexure that may occur between the mount and the camera, plus any additional lash that may exist in the mount, and the overall result should be < +/-5 arc-minute pointing with a perfect polar alignment. I have seen this demonstrated at our observatory.
Overall, I think you should be able to expect the mount to place your object near the center of your camera's field of view when pointing anywhere in the sky. I have yet to hear anything bad about the raw pointing from customers.
Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.
