Sky & Telescope - USA (2019-09)

S&T Test Report by Johnny Horne

AL

L^ P

HO

TO

S^ B

Y^ T

HE

AU

TH

OR

pThe ASIair glows red from its internal LED as

it images M42, the Orion Nebula from atop the

author’s Losmandy Gemini GOTO mount. The

tiny computer, pared with a tablet or smart-

phone, can control up to four accessories,

including an imaging camera, a guide camera,

a Go To mount, and a fi lter wheel or focuser. A

debayered exposure of M42 appears on the iPad

screen running the control app in the foreground.

The

ZWOptical

ASIair

This device eliminates the need

for a laptop when imaging.

SEVERAL YEARS AGO I reached a

milestone in deep-sky astrophotography

in terms of comfort and convenience. I

bought a USB extension cable and was

able to control and monitor my long-

exposure imaging while seated in the

comfort of my warm, mosquito-free van

just a few feet away from my telescope. I

was able to monitor the autoguiding by

looking out the window at numbers on

my ST4’s tracking display and see each

exposure as it downloaded to my laptop

at the end of the USB cable.

Now I’ve reached another milestone.

I can settle into the van and slew my

computerized mount to a target, set an

exposure sequence, acquire a guide star,

and calibrate the autoguider. Within

minutes, I’m taking exposures and see-

ing an auto-stretched preview of each

one as it completes. A familiar-looking

onscreen graph displays the guiding

corrections. And if my imaging involves

targeting the same object on multiple

nights, I can plate-solve the fi eld and

accurately compose the shot to match

the scene recorded on earlier nights.

Oh, and that USB cable? Not needed

... I did all of this wirelessly and with-
out a conventional computer. My laptop
stayed in its case. The closest thing to a
computer required was an iPad.
Between my gear and my iPad was
the ZWO ASIair, a small, wireless USB
hub and Raspberry Pi computer that can
be operated using an iPhone, iPad, or
Android device via a WiFi connection.

On-board Computer

As noted, the ASIair is small and light-

weight, measuring just 3¾ × 2¾ × 1

inches. Each corner has a small rubber

foot, though the unit is intended to be

attached to a telescope OTA or mount

using a supplied pair of hook and loop

fasteners. The package is so small that

it will fi t practically anywhere on a

scope or mount. Four USB 2.0 ports

are located at one end of ASIair as well

ZWOptical ASIair

U.S. Price: $179.95

astronomy-imaging-camera.com

What We Like

Compact size

Attractive pricing

What We Don’t Like

Limited camera compatibility

Connectivity issues

66 SEPTEMBER 2019 • SKY & TELESCOPE

as an Ethernet jack that enables fast

transfer of images stored on the device

to your computer after an imaging ses-

sion. A side-mounted earphone jack and

HDMI port is used strictly for “debug”

purposes according to the manual.

Even though ASIair is compact, there

are lots of features to get to know before

an imaging session can begin. Control

of the unit is done entirely from your

wireless device, as there are no buttons

or switches on the ASIair itself. And

while the ASIair is capable of record-