Re: APM Telescope (175mm) and AP900 weight limits

Eric Baumgartner

Hi, there:

I have had a TMB 175 f/8.0 "classic" (the one with the silver CNC focuser
and silver tube rings) for about two years now. It is a heavier OTA than the
new versions of this scope; I think mine weighs in at 48 lbs, including the
massive rings.

I first mounted it on a new AP900GTO with the 15" ribbed mounting plate
(900RPA), following the lead of a friend who has had good success with this
combination for visual use. Scope vibrations didn't damp out quickly enough
for my tastes, and I have since upgraded to the AP1200 with the 24" ribbed
mounting plate (1200RP). I am very happy with this arrangement. Damping time
is about one second now, and the long tube is much more resistant to
breezes. I think that a lot has to do with the length of the 24" mounting
plate, which spaces the tube rings nearly two feet apart, and thus
significantly reduces the lengths of the cantilevered focus and objective

If I were an imager, I don't think that there would be any question but to
go with the larger A-P mount. As Roland has said on this forum on at least
one occasion, the three most important parts to successful imaging are (1)
the mount, (2) the mount, and (3) the mount.

Hope this helps,

Eric Baumgartner
Redding, CT USA

On 08/17/07 3:23 PM, "r1300rs" <cardiofuse@...> wrote:

I was wondering if the APM 175/1400 (6.9") refractor which weighs in at 39
pounds and 45 pounds with the tube rings and brackets will fit on my new AP900
without too much stress.

The only other additional weight would include the SBIG
Camera/finder/telecompressor; probably another 5-8 pounds. This gives a total
of about 53 pounds.

I see the specs on the AP900 will carry 70 pounds but this scope isf/8 and
close to 60 inches long.

Any thoughts?

You guessed it; I'm on the 4+ year plan for an AP scope.


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