70 SEPTEMBER 2019 • SKY & TELESCOPE
S&T Test Report
the unit is receiving power. After about
15 seconds, the WiFi activates and is
detectable by your tablet or phone. In
darkness the LED also lights up the
entire ASIair case with a gentle red glow.
Select “ASIair” in the list of available
WiFi connections on your device and
launch the ASIair app. Along the top
of the screen is a series of setup icons:
main camera, guide camera, mount,
fi lter wheel, SD card, and three dots
which open more connections, includ-
ing a focuser icon. Click through each
and enter the specifi cs of your equip-
ment. For example, click the telescope
icon to select your specifi c Go To mount
and initiate its connection. You can
then use SkySafari to slew to targets.
Once everything is connected, click
on Preview at the right of the screen,
which opens the operations area of the
app, containing the Focus, Preview, and
Autorun commands. Focus the image
from the main and guide cameras by
monitoring the peak values and FWHM
readings. Once focus is set, open the
guide settings on the left side of the
screen and calibrate the autoguider. This
section of the app appears very similar
to the popular Phd2 guiding program
with its camera connection interface
and graph showing guide corrections.
When all devices are communicat-
ing with the ASIair and autoguiding is
operating, you can then program and
execute an image sequence.
As each exposure completes, the fi le
is saved in FITS format to the MicroSDcard. You can preview images in the
app, which contains an automatic
Screen Stretch function (and automatic
debayer feature, if you’re using a color
camera) that displays a very compelling
preview of your shot.
One of the few problems I had with
ASIair involved an intermittent connec-
tion at the Micro-USB B power jack on
the unit. The ASIair would sometimes
lose power due to this apparent loose
connection, resulting in the freezing
of the app and subsequent restarting,
occasionally rebooting the device itself. I
added a cable tie near the jack to prevent
undue movement of the plug in the
socket, but this helped only marginally.
Perhaps the device requires a sturdier
power jack design? WiFi connection
was occasionally lost when moving
around the mount with my iPad. The 5G
connection, while giving fast transfer
speeds, was most susceptible to disrup-
tions caused by objects between the
ASIair and the operating device.
A warning for users with older
tablets: The app would occasionally lock
up as a full-resolution, debayered image
from my ASI071MC’s 16-megapixel
detector was downloading when con-
trolling the device with my old second-
generation iPad. Deselecting the debayer
option eliminated the problem, as did
downloading smaller region-of-interestimages in full color. Testing with a more
recent iPad eliminated this problem.Summing It All Up
Does a device like ASIair mean that
I forget about my more conventional
deep-sky imaging setups and proce-
dures? That’s a personal choice each
imager can make. I can say that once I
got everything up and running it took
very little time to learn to navigate the
ASIair app and make my mount, guider,
and imaging camera do everything
it could do when using a computer. I
quickly became accustomed to its layout
and operation.
The ASIair is a small package with
high-tech capability costing less than
the cheapest laptops on the market
today. It should be of particular inter-
est to astrophotographers who travel to
dark-sky sites, as well as to beginners
more familiar with apps and tablets.
And while connectivity and compat-
ibility issues were annoying, my advice
there is to stay tuned — ZWOptical has
more planned improvements for the
device, including the support of addi-
tional cameras and mounts.■Contributing Editor JOHNNY HORNE
often reviews imaging equipment for Sky
& Telescope from his home in Stedman,
North Carolina.qZWOptical offers the ASIair paired with an
ASI120MM Mini guide camera, a sensitive
guider with a 1,280 × 960-pixel CMOS array.pThis image of IC 1805 in Cassiopeia consists of ten 600-second exposures made with the setup
seen on page 66.