Sky and Telescope - November 2017 - 65

p Cables for power, the hand control, a USB
computer connection, and an autoguider all
attach to this fixed module on the polar-axis
housing. Thanks to internal wiring there are
no dangling cables for the motor drives. But,
as detailed in the accompanying text, there is
no provision for internal wiring for equipment
mounted on the CGX.

the CGX is the lowest-cost mount that
is fully capable of remote operation.
Almost since the dawn of Go To technology in amateur telescopes, mounts
have included functions that let you
park (or sleep or hibernate) them and
resume observing at a later date without
needing to initialize them to the sky
again. On the surface this sounds like
all that's necessary for a remote setup,
but it is only if something doesn't go
wrong such as a power failure, computer crash, or any of a multitude of
other things that can bedevil a computer-controlled system. To fully qualify
for remote observing, a mount needs
the ability to recover from glitches and
know where it's pointing a telescope
without the need for a human to be
present at the scope. Mounts that can
do this either need a precise homing
ability or absolute position encoders.
The CGX has the former.
I spent a number of nights running the CGX from start to ﬁnish
without setting foot outside the house.
The mount was controlled by a laptop

computer in the observatory running
Celestron PWI software supplied with
the mount. I connected to the laptop
with convention remote-access software
(TeamViewer from teamviewer.com)
and controlled power to the mount and
telescope cameras via internet-accessible
power outlets. Even though I was only a
few hundred feet from the observatory,
I could easily have been any place on
Earth with an internet connection.
The whole remote start-up process
was fast and very straightforward. I'd
power up the mount and cameras,
launch the Celestron PWI program, and
connect to the CGX mount. (The camera and autoguider were operated with
MaxIm DL running simultaneously on
the same laptop.) Once the mount was
connected to Celestron PWI, I'd command it to move to its home position
(with the scope pointed north on the

meridian above the pole), after which
I could begin observing. Everything
worked beautifully.
To test the robustness of the system, I purposely crashed the mount
and/or laptop by killing the power. In
every case I simply powered the equipment back up and repeated the start-up
process. The CGX always moved to its
home position regardless of where it was
pointing when the system crashed.
I tested the initial version of Celestron
PWI, but an update with additional
features is in the works and should
be available soon after this review is
published. The version I tested is very
basic mount-control software. It is not a
planetarium program. The displayed star
map is simply a snapshot of the sky over
the mount showing relatively bright
stars and solar system objects. You can't
zoom in for more detail, but you can

u p The author used the Celestron PWI
software included with the mount for all of
his remote observing. It is a robust but basic
mount-control program and not planetarium
software. The star chart is a "snapshot" of
the current sky over the CGX, and you cannot
zoom in for more detail than is seen here.
u The author especially liked Celestron PWI's
easy-to-use procedure for creating and saving
a pointing model that improves the CGX's Go
To accuracy for current and future observing.
s k y a n d t e l e s c o p e . c o m * N O V E M B E R 2 0 17

65
http://www.teamviewer.com http://www.skyandtelescope.com
Sky and Telescope - November 2017

Table of Contents for the Digital Edition of Sky and Telescope - November 2017
