Sky & Telescope - February 2021 - 33

S These 30-second exposures of the Pleiades star cluster on a hazy, moonlit evening were made with the Evostar and 2-inch focuser working at f/8 (left)
and with the 3.4-inch focuser and f/6.2 focal reducer (right). Insets show analysis of the images with CCD Inspector, revealing that the focal reducer also
flattens the scope's focal plane compared to the curved field inherent to the f/8 objective, and that it would be good for an APS-format detector.

cially in the case of the 150-mm model,
which is available in two flavors.

Hardware
For this review we asked to borrow the
Evostar 150 APO, which is the basic
version of the two 150-mm models.
It's equipped with a dual-speed 2-inch
focuser, lightweight tube rings, and a
Vixen-style dovetail mounting bar. The
other model is the Evostar 150DX APO
Refractor. It has the same objective
and tube assembly but comes with the
heavy-duty, dual-speed focuser found
on the Esprit 150-mm scope, and it's
supplied with heavier tube rings and
a Losmandy-style dovetail bar. These
upgrades cost an additional $850 over
the price of the basic 150-mm scope.
The more-robust focuser on the DX
model brings the advantage of accepting the new f/6.2 focal reducer designed
specifically for the Evostar 150-mm
scope. Because swapping the focusers
on the main Evostar 150 tube assembly
takes only minutes, Sky-Watcher sent
along the upgraded items available with
the DX model so that I could try them
out. Let's start with the basic model.
The Evostar 150 APO is a handsome
scope with its dark, metal-flake painted
tube, white dew cap and focuser, and
Sky-Watcher's signature green trim.
With the focuser retracted its overall
length is 50 inches, and it weighs 17
pounds (3.2 kg). It comes with a very

solid, metal lens cap. The supplied carrying case is also particularly noteworthy for its solid, high-quality construction. It alone weighs 36 pounds and is
made for transporting as well as storing
the scope. The scope is sold without a
finder, star diagonal, or eyepieces. This
might be a negative for a first-time
scope buyer, but for observers who
already own these items it helps keep
the cost of the instrument down, which
I found a plus. There's a dovetail base
for mounting a finder on the focuser
body. While not universal, this format
is relatively common, and I used it to

attach a finder that I commandeered
from another scope.
From the standpoint of visual
observing, I was very happy with the
2-inch Crayford-style focuser. It has
slightly more than 5¼ inches (133 mm)
of travel, and easily accommodated
every eyepiece I tried with and without
a 2-inch star diagonal. I was especially
impressed with the light touch required
to operate the fine-focus knob - something that I really appreciated when
focusing at high magnifications where a
heavier touch would be prone to jiggling
the telescope.

T The author found the 2-inch Crayford-style
focuser to be excellent for visual observing
and even astrophotography with cameras as
heavy as a DSLR. The robust focuser on the
DX model is the same one used on SkyWatcher's premium 150-mm Esprit refractors
and is capable of handling much heavier
imaging setups.

T The optional f/6.2 focal reducer also significantly flattens the Evostar's focal plane for
deep-sky astrophotography. Fitted with a 48mm (large aperture) T-ring, the setup provides
even illumination across a full-frame camera
sensor with only a little vignetting in the very
corners of the image. The focal reducer can be
rotated to aid with framing images.

sk yandtelescope.org * FEBRUARY 2 021

33


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Sky & Telescope - February 2021

Table of Contents for the Digital Edition of Sky & Telescope - February 2021

Contents
Sky & Telescope - February 2021 - Cover1
Sky & Telescope - February 2021 - Cover2
Sky & Telescope - February 2021 - 1
Sky & Telescope - February 2021 - Contents
Sky & Telescope - February 2021 - 3
Sky & Telescope - February 2021 - 4
Sky & Telescope - February 2021 - 5
Sky & Telescope - February 2021 - 6
Sky & Telescope - February 2021 - 7
Sky & Telescope - February 2021 - 8
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