Sky & Telescope - April 2023 QR - 65

remains attached even when the mount
is returned to its case.
The mount and tripod stand just
0.8 meters with the tripod legs fully
extended - a bit low for use with some
refractors and catadioptric scopes. With
its legs retracted, the TC40 measures
about half a meter. ZWO also offers
160-mm, 200-mm, and stackable
70-mm tripod extensions to raise scopes
to a more comfortable height.
The tripod's carbon-fiber legs make it
extremely lightweight (just 2.3 kg). Two
included items help provide increased
stability when using the AM5 with
heavy payloads. First, there are three
steel spikes that replace the tripod's
rounded rubber feet. These spikes dig
into the ground and help anchor the
tripod legs securely. The other accessory
is a triangular weight bag suspended
between the tripod legs with Velcro fasteners.
Small weights can be placed in
the bag to provide additional stability. I
used this feature whenever I had scopes
larger than 4 inches on the mount,
but my 71-mm refractor worked fine
without the weight bag, allowing me to
carry the fully assembled setup outside
for imaging sessions.
You can power the AM5 with a wide
range of 12V DC power supplies that
deliver 5 amps. Although no power
cable is included with the mount, a
12-volt, 5-amp AC
inverter I had on hand
worked flawlessly, as
did a 12-volt, deepcycle
marine battery.
Polar aligning the
tThe small hand controller
for the AM5 is used for
manual slewing and speed
adjustments. All Go To
functions are handled within
the ASI Mount app.
AM5 can be straightforward
or timeconsuming
depending
on whether the user
has an ASIair unit.
The mount doesn't
have a polar-alignment scope or even
a simple sight tube for viewing Polaris.
Polar alignment is best achieved using
the routine with the ASIair. The procedure,
done from within the ASIAIR
app, involves plate-solving (identifying
known star patterns) in several
short exposures recorded through your
telescope with an imaging camera,
then adjusting the mount's altitude
and azimuth motions as directed. The
alignment star field doesn't need to be
near the pole, either - any part of the
sky except due east and west will work.
That makes accurate polar alignment
easy even when you have set up without
a clear view of the celestial pole. Polar
alignment without the ASIair can be
done using the star-drift method.
Although a mounting shoe is provided
on the side of the AM5 housing
intended for an ASIair or a small polar
finder on a standard
quick-release bracket, I
preferred mounting the
ASIair directly on the
tube of my telescopes
because that location
provides a minimum of cables running
to the mount that could snag during
slews or tracking.
The AM5 saddle accepts both
Vixen-style dovetail bars and the wider
Losmandy-style mounting bars. Two
locking jaws with large knobs ensure
any telescope riding on the AM5 is
securely held in place.
" Weightless " with the AM5
One of the attractive features of the
AM5 with its strain-wave gearing is
that given the motors' extreme rigidity
and high torque, they can drive payloads
up to 13 kg without adding any
counterweights.
Like other strain-wave-driven
mounts, you can forget about loosening
clutches to balance the scope. The
only way either axis can be adjusted is
with the hand controller or computer
The generous space between the saddle
and the declination housing allows the AM5 to
track up to 20° past the meridian, depending
on the specific telescope attached. The two
saddle clamping knobs make tightening the
saddle clamps easy. A mounting shoe for the
company's ASIair controllers is attached to this
side of the housing. Also visible is a 12-volt,
3-amp power output socket.
The polar-axis controls and locking levers
on the AM5 are large and easy to grip. Note
the latitude is adjustable from 0 to 90 degrees,
permitting the mount to be used in either altazimuth
or equatorial modes.
Along with a whimsical graphic, the pole-facing
side of the AM5 contains a USB computer
connection, ST-4-style Auto Guide port, hand
controller (HC) input, and power input port
(though the mount does not include a power
cable). The LED at left shines steady red when
the mount is powered up in equatorial mode, or
green in alt-azimuth mode.
sk yand tele scope .o r g * APRIL 2023 65
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Sky & Telescope - April 2023 QR

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