Sky & Telescope - December 2020 - 69

"Save image" button in a different tab
and several taps away from the overlay's
on/off toggle. In addition to the operator, up to 9 others can connect with
"Status: Watcher" and save images on
their own devices.
Both live-view mode and enhanced
vision default to auto-exposure, but you
can turn that off and make manual
adjustments to gain (equivalent to ISO
speed), exposure time, brightness, and
contrast. This gives you wide latitude
in ﬁne-tuning the image quality, which
advanced users will appreciate. I found
it particularly helpful in adjusting the
eyepiece image, which if left too bright
illuminates the inside of the barrel,
which Unistellar should consider roughening or ﬂocking with felt or some
other absorber/diffuser.

Citizen Science Made Easy
One of the features that distinguishes
the eVscope is a close partnership
between Unistellar and the SETI Insti-

The 114-mm
(4½-inch) f/4 primary mirror reflects
incoming starlight
not to a secondary
mirror, but to a sensitive Sony IMX224
CMOS imaging
sensor with 1,280
by 960 pixels, each
3.75 microns square
(inset).

tute. Franck Marchis,
Senior Astronomer at
the latter and Chief
Scientiﬁc Ofﬁcer at the
former, has worked to
ensure that eVscope users
interested in contributing
to astronomical research
can do so as easily as they
can take astrophotos.
The partners envision
having widely distributed observers capturing
asteroid occultations and
exoplanet transits, monitoring cometary activity,
and recording supernovae
and other transients. The Unistellar app
includes a "Science" tab, but much of
what's there is grayed out while development and beta-testing continue.
I asked Marchis if I could test the
eVscope's citizen-science functionality. He responded by having a colleague
send me step-by-step instructions for
recording stellar light curves along with
predictions for some upcoming exoplanet transits. The recipe was simple
and clear, and on two successive nights

W In the app's Explore tab,
you can specify which parts
of the sky are accessible from
your observing site and/or
where you'd prefer not to observe to avoid looking through
too much atmosphere. In
this example, the eVscope is
set to ignore targets below
30° altitude and in a range of
western azimuths where, say,
the view is blocked by tall
trees or buildings. The app
won't let you point within 5°
of the zenith because alt-az
Go To mounts have trouble
adjusting their aim in this part
of the sky.

I managed to record - via hours-long
series of 3.95-second exposures - the
passage of two different exoplanets in
front of their host stars. One blocked
2.8% of its star's light, the other just
1.3% - the shallowest transit detected
with an eVscope to date. And this with a
4½-inch telescope!
I had to download my eVscope image
sequences from the onboard memory
to my iPhone, then upload them to
Unistellar. SETI Institute scientists did

T Left: When you ask the eVscope to show you a celestial object - in this case M104, the Sombrero Galaxy in Virgo - it starts out in live-view mode, displaying a nonstop series of fraction-ofa-second exposures. The galaxy is much more obvious than it would be in an ordinary 4½-inch
reflector, but it's not particularly attractive. Middle: Tap the eye-and-stars icon to launch enhancedvision (eV) mode; you'll now see an animated display of planets orbiting a star while you wait for a
several-second exposure to accumulate. Right: Once eV mode kicks in, you'll see a much better
image that gets more spectacular as it coadds additional exposures. The image on your device
screen can also be viewed in the eVscope's eyepiece.

sk yandtelescope.org * DECEMBER 2 02 0

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Sky & Telescope - December 2020

Table of Contents for the Digital Edition of Sky & Telescope - December 2020