Sky & Telescope - June 2019 - 71

exposure imaging. It's worth noting
that the supplied USB 3.0 cable is only
5 feet long. I was able to keep my laptop
close enough to my telescopes to work
with a cable this short, but others may
need some form of extension such as an
active USB 3.0 cable or the addition of a
powered USB hub.
There are two USB 2.0 ports on the
DSI-IV for connecting ﬁlter wheels,
focusers, and guide cameras. But
note that although these ports are
powered, they still draw their power
from the USB 3.0 connection. I successfully tested two small cameras on
these ports, but your mileage may vary
depending on how much power your
auxiliary equipment requires.

Getting Started
Following instructions in the DSI-IV's
quick-start guide, it was a breeze installing the camera's supplied operating
software (called Meade SkyCapture),
ASCOM drivers (needed for operating
the camera with third-party software),
and a copy of the user's manual on
my aging laptop with an Intel i7 Core
processor running Windows 7. At ﬁrst
blush, the manual I installed from
the CD-ROM sent with the camera
appeared to be the same as the one that
opens from the Help menu in SkyCapture, but it was actually an older version
that had not been updated for the
DSI-IV - stick with the version that's
displayed by SkyCapture's Help menu.
Using my own adapters, I attached a
conventional camera lens to the DSI-IV
and began bench-testing the camera.
The ASCOM driver worked ﬁne, allowing me to connect the DSI-IV with
the software I typically use, including
MaxIm DL for long-exposure imaging,
and FireCapture for recording astronomical video clips. But for the sake of
the review I wanted to work with the
supplied software.
SkyCapture is a slick-looking program with a user interface that I found
relatively easy to navigate. It works with
a variety of Meade cameras, and it has a
number of features for Meade's oneshot color cameras that I couldn't test
with the monochrome DSI-IV. Never-

p Left: The DSI-IV only needs its USB 3.0 (it's backwards compatible for USB 2.0 as well) connection to a computer to capture images. The 12-volt input is just for the thermoelectric cooling
system and is really needed only for long-exposure imaging. See the text for details about the two
USB 2.0 ports. Right: Eight small heating elements bonded to the perimeter of the CMOS chamber
window were 100% effective at keeping the window fog-free during all of the author's testing.

theless, within minutes I was capturing
video clips and snapping still images,
although my "long" exposures were
limited to only a few seconds because
of the bright workshop environment
(more about this later). There are always
bumps on the road to learning any new
software, and I certainly encountered
my share, but nothing struck me as
being due more to the software than
my own inexperience using it. Much of
my time was spent learning the video
controls. Once comfortable with them
it was time to get outside.

Going for the Moon
With the exception of Mars, which
at the time was way too small for my
imaging setups, all the major planets
were in the morning sky, so my video

tests were all done shooting the Moon.
Mead claims The DSI-IV is capable of
video frame rates as high as 23 per
second at full resolution, but most users
will experience lower rates, especially
when running the camera in the preferred 12-bit, rather than 8-bit, mode.
The issue is not so much the camera
as it is how fast your computer can
transfer and save images. The solid-state
drive in my laptop isn't as fast as the
latest models. You can certainly speed
frame rates up by reducing the area of
the CMOS that's being recorded (using
cropped frames or what SkyCapture
calls ROI for "region of interest"). This
is especially true when imaging planets
since there's little advantage to recording the blank sky that typically appears
in the frame. Even with the Moon I
reduced the size of the recorded frame
to isolate lunar features rather than the
large sweeps of lunar landscape seen in
full-frame videos. Using a small region
of interest, I typically captured between
40 and 50 frames per second.
Frame rates aside, what really caught
my attention with the DSI-IV is the
enormous ﬁles generated with even
short videos, often exceeding four gigat The DSI-IV is an excellent performer when
shooting astronomical video clips, even if
the author's results were less than stunning
because of his winter seeing conditions living
in New England under the jet stream. This view
of Schröter's Valley was processed from 200
frames selected from a 1,600-frame, 30-second video clip captured last February 16th.
sk yandtele scope.com * J U N E 2 019

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Sky & Telescope - June 2019

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