62 March 2014 sky & telescopeS&T Test ReportNotes from the Field
Despite its unusual design, the ZEQ25GT sets up and
operates just the same as a conventional German equato-
rial, and anyone familiar with a traditional equatorial
mount will have no problems using this one. Further-
more, the heavily illustrated Quick Start Guide clearly
explains the basics as well as features specifi c to the
ZEQ25GT, such as the quick-release “gear switch” that
disengages the worm gears from the worm wheels on theright ascension and declinations axes. When the gears are
disengaged, the axes swing freely, making it very easy for
you to precisely balance the mount on both axes.
The mount we borrowed from iOptron for this review
came with an optional polar alignment scope. As I’ve
mentioned in previous reviews of iOptron equipment, I’m
very impressed with this alignment system for its simplic-
ity and accuracy. The scope’s illuminated reticle has two
sets of concentric rings graduated into 12 hours. They
are for use with Polaris in the Northern Hemisphere
and Sigma Octantis in the Southern. Based on the date,
time, and location stored in the mount’s electronics (more
about this in a moment), the hand control graphically
displays where you need to position either of these stars
on the reticle to achieve accurate polar alignment. There
are no calculations necessary on the user’s part.
For example, let’s say the hand control indicates put-
ting Polaris at the 7h 30 m mark. You just view through
the polar scope and use the fi ne-motion screws on the
mount’s azimuth and altitude adjustments to move
Polaris in the fi eld of view until it’s at the reticle’s 7h
30 m mark and you’re done. If you own an Apple mobile
device running iOS 6.0 or later, I highly recommend you
purchase iOptron’s Polar Scope app ($1.99 from the iTunes
App Store — search for “iOptron”). I fi nd the app visually
easier to use for determining the alignment star’s correct
position on the reticle.
The ZEQ25GT has a built-in GPS receiver for auto-
matically setting the mount’s date, time, and geographical
coordinates. But there’s a caveat. The receiver’s antenna
is located in the mount’s main electronics module, which
is attached to the top of the polar-axis housing. As such,
it does not have a clear view of the sky when the mount
is set up in its initial “home” position with the telescope
above the polar axis and pointed toward the celestial pole.
In this position, the declination drive blocks the antenna’s
sky access, which is needed to get a fi x from the GPS sat-Far left: To help with
balancing the mount,
the right ascension
and declination drives
have gear switches
(arrowed) that release
the worms from their
worm wheels. Near
left: The hand control
has variable-bright-
ness illumination for
the display and but-
tons. The illumination
automatically turns off
during periods of inac-
tivity, but returns the
moment any button is
pressed.The mount is available with an optional hard-sided carrying case
and soft-padded tripod bag with shoulder straps.STTR layout2.indd 62 12/23/13 11:39 AM