Drift Error Calculator?
Posted 05 August 2013 - 01:17 AM
The rotation rate of the motors appears to be correct, and the swing arm distance hasn't changed. I use a laser for polar alignment, and the laser is aligned to the swing axis within 0.25 degrees if not less, so any polar alignment errors are small.
I was thinking of writing a program to analyze the images and, knowing (or calculating) the field position and orientation, the streak length and direction, and the exposure time, determine the source and magnitude of the error. Thus, if it's a polar alignment error, it would give information about how many degrees away from the celestial axis the alignment would have to be to produce the observe errors. Or, if the RA slewing rate is off, it could give precise values for this errors.
Does something like this already exist?
Here is an example photo I'd feed the program (1 minute at 105mm). Full version shows the tracking error:
Posted 05 August 2013 - 04:32 PM
I compared frames captured sequentially, each a minute long, and realized there was some drift, but it was small (2-3 pixels) and nearly perpendicular to the trailing direction. However, I saw trailing in the same direction and length in frames I looked at.
Thus, excluding movement from shutter slap, the trailing I'm seeing must be some kind of periodic error that is a combined result of slight lateral play in the hinge I'm using (thoughts here?) and imperfect gear alignment.
Posted 05 August 2013 - 06:34 PM
Posted 05 August 2013 - 06:43 PM
Posted 06 August 2013 - 02:46 AM
Posted 06 August 2013 - 04:07 PM