Precision-Adjust Rotating Pier Adapter with Azimuth Bearing (900RPA)
This pier adapter was designed for very accurate and smooth adjustment of the azimuth angle without
loosening the lock-down knobs on the base of the mount. The top plate of the adapter rotates through the
900GTO mount’s full 15 degrees of azimuth motion. (It does not rotate through a full 360 degrees!) This
Rotating Pier Adapter is the ideal choice for portable setups as it makes azimuth adjustment so easy.
Upgrade your previous model 900 mount (any version) and enjoy the ease of use. Do a setup, followed by
a fine polar alignment at a remote site just once, and you will wonder how you ever got along without this
pier adapter!
The adapter includes two machined flat plates, four machined aluminum lock knobs with washers, a tall
version of the azimuth adjuster block, the center pivot screw and six 5/16-18 x 5/8 button head screws and
washers.
Attach to an Astro-Physics pier: Simply fit the Rotating Pier Adapter
into your Astro-Physics Portable Pier just like the Standard Pier
Adapter (900SPA) and fasten it from the side with the six screws and
washers provided. Make sure that the Azimuth Adjuster Block is on
the north side.
Attach to a flat surface on your own pier: The Rotating Pier Adapter
must fit inside another part and be bolted from the side. It cannot be
bolted through the top as you can with the Standard Pier Adapter.
For custom installations, we recommend our 900 Flat Surface
Adapter (900FSA). The Flat Surface Adapter bolts onto the flat plate
on top of your pier or tripod, then the Rotating Pier Adapter slips in
(just as it fits into our pier) and you fasten from the side with the six
screws and washers provided with the Rotating Pier Adapter. The
bolt circle for attaching the 900 Flat Surface Adapter to your pier is
7.230” diameter. The Flat Surface Adapter requires that the top
plate of your pier be at least 7 3/4” in diameter.
Using an ATS pier:If you plan to use an ATS pier, the O.D. of the
plate will need to be modified by ATS for an additional charge.
How does it work? Like most really good ideas, it is actually
quite simple. The bottom plate of the 900 Rotating Pier Adapt
fastened to your pier or tripod – it does not move. The Azimuth
Adjuster Block is attached to the bottom plate – it also does not move.
The top plate fits snugly into the bottom plate. Because of the tight fit,
the smooth bearing surface and the two recessed tension adjustment
screws, the top plate will rotate inside the bottom plate with absolutely
no play or wiggle. The movement, although velvety smooth, is quite
stiff – as it should be. The top plate has a slot through which the
Azimuth Adjuster Block protrudes. The slot allows the top plate to be
rotated through the 900GTO’s full 15 degrees of azimuth adjustment.
Your mount is fastened to the top plate and rotates along with the top
plate as you screw your mount’s Azimuth Adjusters against the
Azimuth Adjuster Block. The opposing Azimuth Adjuster Knob then
holds the whole thing in place once you are adequately polar aligned.
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Note #1: The two recessed screws (3/16 hex), shown by the arrows, adjust the tension between the two
plates of the Rotating Pier Adapter. These are preset to an optimal tension and should rarely, if ever, need
to be re-adjusted. You do not need to tighten or loosen these two screws as part of your normal polar
alignment routine.
Note #2: The Rotating Pier Adapter will work best with the Heavy Duty Azimuth Adjuster which is
standard on all 900GTO mounts produced after August, 2005 and is available as an upgrade (9AZKIT) to
older mounts. See our website for details.
