Sky and Telescope - March 2017 - 61

at about 27 pounds (12.2 kg) or almost
twice the weight of the FSQ-106ED.
But the real eye-opening increase is
the price - at $13,150 the new scope
is nearly two and a half times more
expensive than its predecessor. With
such added cost comes the expectation
of uncompromising performance, and
that's the standard by which I judged
the FSQ-130ED that we borrowed from
Texas Nautical Repair for testing last
spring and summer.

A LL PHOTOS BY THE AU THOR / ASTRONO MICA L IM AG ES PROCESSED BY SE A N WA LK ER

First the Basics
The FSQ-130ED is a 130-mm (5.1-inch)
f/5 refractor with a 5-element optical
system, which Takahashi proclaims
as the "ultimate model of the Takahashi FSQ series." The 3-element front
objective and 2-element rear corrector
include three lenses made from what
the manufacturer calls "super ED glass"
(where the ED stands for extra-low
dispersion) that is capable of correcting
spherical and longitudinal chromatic
aberrations to "almost zero."
The scope has a nominal focal length
of 650 mm (25.6 inches), but there are
optional 0.73x and 0.60x focal reducers that deliver effective focal lengths
of 470 mm (f/3.6) and 390 mm (f/3.0),
respectively. These focal reducers each
produce a usable imaging circle 44 mm
in diameter, which is large enough for
full-frame DSLR cameras and astronomical cameras built around the
popular KAF-11000 CCD sensor. There
are also 1.5x and 1.6x focal extend-

ers for the FSQ-130ED that yield 980
mm (f/7.5) and 1,040 mm (f/8.0) local
lengths with the same 44-mm imaging
circle. I didn't test these accessories, but
Takahashi is known for living up to its
optical speciﬁcations.
With its 650-mm focal length, the
FSQ-130ED has a native image scale
of 317 arcseconds per millimeter. But
the most impressive spec is the scope's
huge 110-mm imaging circle that spans
a whopping 9.7° of sky. This imaging circle far exceeds the grasp of any
CCD camera currently intended for the
amateur market, or, for that matter,
anything on the foreseeable horizon.
The largest cameras I used on the scope
have KAF-16803 CCD chips, which
covered a 3¼°-wide ﬁeld of view with a
resolution of 2.86 arcseconds per pixel.
But on paper the FSQ-130ED would be
an incredible scope to pair with FLI's
new MicroLine 50100 camera with its
KAF-50100 CCD sensor (ﬂicamera.
com/microline/index.html). This setup
would cover a 41/3° x 3¼° swath of sky
at a resolution of 1.9 arcseconds per
pixel - excellent parameters for a f/5
wide-ﬁeld, deep-sky imaging setup.
With its dew shield retracted and no
adapters attached to the focuser, the
FSQ-130ED is impressively compact,
being slightly less than 21 inches (53
cm) long. As such it would ﬁt diagonally
into standard carry-on airline luggage,
though it might exceed the weight limits
of some airlines. The scope's overall construction is exceptionally robust, living

p The telescope's 3-element objective and 2-element rear corrector include three lenses made
from "super" extra-low-dispersion glass.

p All astronomical images accompanying this
review were made with the Takahashi FSQ130ED astrograph mounted on a Paramount
MX in the author's backyard observatory under
moderately light-polluted skies less than 20
miles from the heart of downtown Boston.

up to Takahashi's well-deserved reputation for building rugged equipment.
This is especially true of the precision 5-inch dual-speed, rack-and-pinion
focuser and 360° camera rotator. The
focuser has just 35 mm of travel and is
so smooth and friction-free that even
light cameras will cause the drawtube to
slide outward when the scope is pointed
at high elevations. To prevent this from
happening there's a locking lever that
doubles as an adjustable-friction clutch
on the focus knob. It worked very well,
and even when I set the friction high
enough to securely hold my heaviest CCD camera in place, I could still
ﬁnesse the focus with the hand knobs,
including the 10:1 ﬁne-focus knob.
This was an unexpected beneﬁt since
the majority of dual-speed focusers I've
used in the past simply let their ﬁnefocus knobs slip when the drawtubes
were "locked" down. The only issues I
had with the focuser involved the relatively short travel of the drawtube, and
I'll return to this in a moment.
In addition to my Apogee and FLI
CCD cameras mentioned above with
KAF-16803 chips, I also tested the FSQ130ED visually and with a full-frame
s k y a n d t e l e s c o p e .c o m

* MARCH 2017

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Sky and Telescope - March 2017

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