Hi David,
I see ASA is also making a mount with a similar approach.
There is also an advanced low friction coating that is quite cheap that is
claimed to reduce PE considerably on all mounts.
http://www.andysshotglass.com/astromo_mod_store.html
Perhaps a combination of both would setup the mount to be
able to have just a slow autoguiding like once a minute to correct
for flexure or slow polar alignment drift.
In my experience with a few mounts, exact polar alignment and
balance is one of the most important factors.
Self guiding is good but limited. Blue filters often stretch the
guide times out longer than ideal for the mount and the guide chip is tiny
and very low resolution which weakens the result. I get far better results
with an external guide scope.
I also find guide star selection can really make a big difference.
If I get higher than expected guide errors I pick another star. I often see
the right star giving 1/3rd the error of another star. Often the brighter stars
are a bit bloated and the centre of the star being computed by software may be
more prone to error than a tight small star. With self guiding your
choice of stars is very limited and none of them are what you would call
tight.This is why I like the ST402ME for the guide camera. It is similar to the
Starfish in FOV and is cooled and I can get quite good resolution for gudie stars
using a cheap AT66ED lightwieght scope that does not seem to flex (20mins seems fine
if not windy and polar alignment is OK) 30 mins is also fine. This is a Tak NJP mount and
its PE is around 2 arc seconds by itself.
If I read the site correctly it seems you can also use an AO device with this as well.
So wouldn't the best of both worlds be the gears coated with low friction coatings, the TDM,
the AO and then an autoguider set for 1 minute corrections to pick up flexures. Perhaps that would
be a super setup. SBIG are releasing their new standalone autoguider with an artificial star to correct
for flexure as well as normal corrections. That'd be a beauty.
Greg.