Sky and Telescope - July 2016 - 63

prototype, in part because the primary and secondary
mirrors were hyperboloids and thus deemed too diﬃcult
to fabricate and test.
Decades passed before a Ritchey-Chrétien scope (or
RC for short) was tested photographically on the sky.
And it wasn't until 1955, 10 years after Ritchey's death,
that a 40-inch RC he built for the United States Naval
Observatory was relocated to Arizona and began producing Ritchey's long-promised results. Indeed, the ultimate
success of the 40-inch paved the way for the design being
adopted for virtually every large-aperture professional
telescope made during the next half century, including
the Hubble Space Telescope.
In the early 2000s, amateurs too turned to the
Ritchey-Chrétien design as they transitioned from ﬁ lmbased to digital astrophotography and wanted large-aperture telescopes capable of delivering quality star images
across the digital detectors then becoming available.
Those RCs were expensive, but so too were large-format
digital cameras, and most amateurs able to aﬀord one
could also aﬀord the other.
Today, however, astrophotographers are using a wide
range of modestly priced digital cameras, including
DSLRs, and that's driving a market for suitable imaging
telescopes that are also modestly priced. And for many,
the new line of Astro-Tech truss-tube RCs ﬁlls the bill.
Costing a fraction of what previous RCs cost, some must
wonder if the manufacturer cut corners or sacriﬁced
quality. To ﬁnd out, we borrowed the Astro-Tech 14-inch
RC from Astronomics, and I tested it last fall and winter
from my suburban-Boston backyard observatory.

As detailed in the text, the scope proved to be a delight for
visual deep-sky observing even though Ritchey-Chrétiens are
most often considered as imaging instruments. The supplied
3-inch Crayford-style focuser was ﬁne for eyepieces and lightweight cameras, but struggled with heavy imaging setups.

inches outside the back of the telescope. This is more
than enough room to ﬁt even complex imaging setups
that include, say, a ﬂip mirror, oﬀ-axis guider, motorized
focuser, ﬁlter wheel, and camera. Given that imaging
setups can weigh 15 pounds or more, and a guide scope
can add a few more pounds, the AT14RCT should be used
with a mount rated for at least 90 pounds. That's the suggested limit for Software Bisque's original Paramount
MX that I used for all of my testing. It worked well in
all but the windiest conditions when I was using a guide
scope and very heavy camera.
I was in for an unexpected treat on my ﬁrst night.
Impressive Specs
To check the optical collimation, I slipped a high-power
On paper the AT14RCT looks incredible for a telescope
eyepiece into the focuser and examined the image of a
costing $5,795, given that 14-inch RCs in the past were
bright star. The collimation was spot on, so I switched
priced well into the 5-digit range. In addition to the
to a low-power eyepiece to see if stars appeared uniform
carbon-ﬁber truss tube, a trio of cooling fans for the priacross a larger ﬁeld. They did. Furthermore, the view
mary mirror, a dual-speed 3-inch Crayford-style focuser,
was beautiful, with the subtle hues of stars clearly visible
and a pair of Losmandy-style dovetail mounting bars, the - this is after all a 14-inch telescope.
scope features both mirrors made of fused quartz. With
To make a long story short, on more than one occathe exception of Questar telescopes, this thermally stable sion I spent an entire night using the AT14RCT with eyematerial has rarely been oﬀered as an option for amateur pieces. It's a very nice visual telescope, which is somescopes (and even in the case of the already
thing I hadn't considered beforehand
WHAT WE LIKE:
pricy Questar, a quartz mirror added a
given that RCs are mainly promoted for
roughly 25% premium to the cost).
their imaging qualities. The scope has a
Excellent optical quality and
focus stability
Out of the box, the AT14RCT looks
focal length of 2,834 mm (my measureevery bit as good as its speciﬁcations do
ment), yielding an image scale of 72.7
Fused-quartz mirrors with 99%
reﬂective coatings
on paper. The machining is ﬁrst rate, and
arcseconds/mm. As such the maximum
the ﬁt and ﬁnish excellent. Without the
ﬁeld of view possible with a 2-inch
Rigid carbon-ﬁber truss tube
focuser attached, the scope weighs about
eyepiece is almost 1°° across - pretty
WHAT WE DON'T LIKE:
decent for a 14-inch Cassegrain system.
65 pounds (29 kg). At its widest part, the
Requires a focuser upgrade for
Visual observing also highlighted
tube is 20½ inches (52 cm) across, and
use with heavy cameras (but to
the advantages of the scope's quartz
excluding the focuser it's 39 inches long.
be fair, this is clearly stated in
optics. I typically open my observatory
The scope has a ﬁxed focus, which
the scope's documentation)
roof at least an hour before using any
I measured as falling almost exactly 11
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Sky and Telescope - July 2016

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