On Friday, November 16, 2018 at 6:54:52 AM UTC-8, Chris L Peterson wrote:
On Thu, 15 Nov 2018 22:07:42 -0800 (PST), palsing
wrote:

On Thursday, November 15, 2018 at 9:12:34 PM UTC-8, Chris L Peterson wrote:

Any number of $1500 mounts will do the same these days.

Well, no such mounts for my 25" Obsession dob :).

... but now I
have an old smartphone strapped to the side of the 16" tube, and its
gravity sensor let me position the scope accurately enough that my
target is always near the center of the eyepiece, just reading the
numbers. A setting circle system that looks directly at the scope
position, not the mount at all. You can slap that on a Dob.

OK, I'm intrigued about this old smartphone setting circle system of yours. Can you elaborate for me, please? I have a couple of old smartphones that I now use only for holding a bunch of music to play when in the field observing...

\Paul A