Well, I finally got out in the garage today and drilled the 3/4" x 12" round base plate for my pier. I think I will end up purchasing a Pier-Tech 3 since I don't have a lot of time to be building. My thought was to have Pier Tech attach my plate to the bottom of the mount for me and then ship the completed unit.
Does anyone know if the pier tech's pier and/or mounting base is aluminum or steel? Obviously, we can't weld aluminum to steel.
I also have a question on Polar Alignment. It seems to me that with a robotic, programmable mount like the Paramount that it would not be necessary to orient the pier to true north. Couldn't a guy find true north after the telescope and pier is mounted, and then set something in the program so that the software would always know where true north is? Am I missing something?
Sorry, if the polar alignment question might be a silly question. I haven't had time to look at astronomy stuff since last fall and I've already forgotten a lot. I'm just trying to get back up to speed starting today!
I am sure you have discovered in the past 2.5 years or so since your post, that there are some things about alignment to the true pole that no amount of robotics software can hide. True, software can compensate for pointing errors in GoTo slews. These could be caused by mount construction error (not perpendicular between axles and optics is common). Also, atmospheric refraction could be entered for compensation. But most programs like this for tracking and guiding do not try to correct the effects of polar alignment angle error, as far as I know.
Most serious of these is field rotation. This is most severe with alt-azimuth mounts, where the amount of misalignment to the true pole is the distance from true pole to local zenith. Antarctica's Scott Station observers at the pole can get away with a zero error, but everyone else will see field rotation to some degree. How much depends upon the error.
Field rotation causes stars, even if perfectly tracked at the center of the picture, slowly to revolve around that center. Amount depends upon error angle and duration of an exposure, and also upon effective focal length. And sometimes there is minimal effect in some areas of the sky, even for alt-azimuth mounts. But rotation errors can show up as smeared stars over multiple pixels in the corners of the CCD chip even after a few seconds at high magnification.
Also there is declination axis drift caused by an error of alignment. Some expouse purposeful misalignment to take care of backlash in DEC axis corrections. Some think this is solving one problem by creating another.
Ideally, as one images around the meridian at near overhead pointing, there should be no DEC correction needed at all with a properly aligned mount. And only atmospheric refraction, PEC for the driving gearing in RA axis, and wind or optical axis shifting should be the things that need to be considered.
I have built various types of equatorial mounts, and used commercial GoTo mounts with remarkable software, but I still have found no substitute for close polar alignment in the last 50 years. Gregg