taken, the period between
exposures, and the number of
exposures. Some intervalom-
eters even allow you to set the
time between mirror lockup
and exposure, since the mirror
lockup introduces vibration in
the system.
Camera settings
The LighTrack II Mount
from Fornax is easy to assemble
and use. The company also sells
the optional FMW-200 wedge
and polar alignment scope.
ASTRONOMY: WILLIAM ZUBACK
The constellations Andromeda and Triangulum (with their two large galaxies)
dominate this wide-field shot taken through a Canon 6D with a 47mm lens
mounted on a Sky-Watcher Star Adventurer tracking mount. JOHN CHUMACK
is not as important as it is when
you’re planning to use a CCD
or DSLR through the telescope,
yet this does depend on the
length of the exposure.
Other beneficial accessories
include a reasonable-size mem-
ory card that allows you to
quickly download exposures, a
fully charged battery or an
external power supply, and an
intervalometer. I also carry
spare memory cards and
charged batteries with me.
The intervalometer is an
important accessory. It allows
you to program and control the
length of your exposures with-
out touching the camera, so
64
A ST R O N O M Y • MAY 2018
that you avoid inducing vibra-
tions that can ruin your expo-
sures. Canon refers to its
intervalometer as a Timer/
Remote Controller; Nikon calls
it a Multi-Function Remote
Cord; and Sony calls it a
Remote Commander. Be cer-
tain you check your camera
model compatibility if you pur-
chase this accessory.
With an intervalometer, you
can set the length of each expo-
sure when you set your camera
to “bulb” on some DSLRs or
“manual” on others. With most
intervalometers, you can set the
time between activation and
when the first exposure is
Proper camera and lens settings
will not only save you a lot of
frustration, but also noticeably
improve the quality of your
images. And the beauty of digi-
tal media is that you can delete
and reshoot — unless your
subject is a total solar eclipse or
a magnificent fireball.
Turn off the lens autofocus:
Many camera lenses — in your
smartphone, point-and-shoot
camera, and most DSLR lenses
— have a feature called autofo-
cus. For taking general photos
of people and scenery, this is an
invaluable feature, but not so
for astrophotography. If you
leave the camera DSLR lens on
autofocus when taking astro-
nomical images, the lens will
perceive the sky as blank and
continually search for the
focus. Autofocus also drains
your battery.
Turn off your flash: This
one might seem obvious, but
I’ve seen instances when a nov-
ice did not know to turn off the
flash, or an experienced imager
forgot to do so. This is one of
the reasons why I still use a
checklist when I prepare for a
night of astrophotography.
Mirror lockup: This lets
you lock the mirror before you
begin imaging. In normal oper-
ation, when the mirror swings
out of the way as you start an
exposure, the motion intro-
duces a vibration into the sys-
tem. This is not a problem for
normal, handheld, usually
short exposures, but it can
Celestron’s Advanced VX
Mount has a maximum weight
capacity of 30 pounds (13.6
kilograms). Counterweights
and a tripod are included.
COURTESY OF CELESTRON
cause problems for exposures
when you want stars to appear
as points of light, rather than
squiggly lines.
Set the white balance
to auto: White balance lets you
adjust colors so that the image
looks natural in its setting.
This is great if you are shooting
a wedding under some unusual
lighting, or skiers against
bright white snow, but it’s
not necessary for nightscapes.
So, leave the white balance
on auto.
ISO setting range: The
measure of the camera sensor’s
sensitivity setting is the ISO, a
photographic standard adopted
during the film days by the
International Organization for
Standardization. Most digital
cameras start at a low sensitiv-
ity of 100 ISO (or even 64 ISO)
and range to 102,400 ISO on
high-end cameras. Although a
high ISO setting would seem
ideal for low-light astronomical
imaging, there is an important
trade-off. As you increase the
ISO, you increase electronic
noise. I prefer to image at a
maximum of 400 ISO. But the
noise-suppression software in
your camera may work won-
ders. Experiment with higher