partially been reignited
through the work of The World
at Night (TWAN). Initiated by
Babak Tafreshi and Mike
Simmons through Astronomers
Without Borders, the 30 or so
regular TWAN photographers
(and many others) have con-
tributed well-composed images
and time-lapse videos of celes-
tial objects with interesting
natural or human-made land-
marks in the foreground. The
phrases “lightscape imaging”
or “light painting” are often
used to describe such work.
Necessities
What do you need to create
wide-field astronomical images
of your own? First, get a camera
that will allow a number of set-
tings for long-exposure photog-
raphy. I define “long exposure”
here as anything greater than
1 second. The digital single-
lens reflex camera, or DSLR,
is a great choice. Price points
for DSLRs range from several
hundred to thousands of dollars.
And what you may have heard is
true — you can take high-quali-
ty tracked astrophotos with one
of the lower-priced DSLRs.
An alternative to the DSLR
has emerged: the mirrorless
camera. This version doesn’t
need a mechanical mirror to
switch between the viewfinder
and the sensor. Manufacturers
can reduce the camera’s overall
complexity, weight, and size by
replacing the optical viewfinder
with a digital version. This also
eliminates a vibration source in
the system. There are some
pros and cons: Most mirrorless
cameras have reduced-size sen-
sors, require specific mirrorless
camera lenses or a special lens
adapter, and use battery power
at a faster rate than DSLRs.
Sony and Fuji are currently the
leaders in mirrorless cameras.
Like the DSLR, these will con-
tinue to evolve.
Next, invest in a good cam-
era lens. Most of today’s DSLR
lenses easily meet that require-
ment, even those referred to as
kit lenses (less expensive lenses
These superb full-frame cameras for astroimaging use different tech. The Canon 6D (right) is a standard DSLR
that employs a mirror to send the image to the viewfinder. The Sony a7R II is a mirrorless digital camera. COURTESY
OF THE MANUFACTURERS
included with the purchase of a
DSLR). Lens autofocus and
image stabilization features are
not necessary and actually can
cause problems. Your lens focal
length should not be too long. I
usually consider anything lon-
ger than a 135-millimeter tele-
photo lens to be too long,
though I often shoot through
telephoto lenses.
One discussion you might
hear is whether you should use
a zoom lens. Today’s zoom
lenses are much better than
those of 30 years ago, back in
the film era. The glass used to
make lenses is of higher quality,
and the lens mechanics are
greatly improved. I have had
good success using zoom lenses
for astrophotography. With a
zoom lens, I have the flexibility
to create a specific field of view.
Another advantage is having
multiple focal lengths available
in one lens instead of buying
several fixed-focal-length
lenses. I use both zoom and
fixed lenses for astrophotogra-
phy, yet find myself almost
entirely using zoom lenses for
regular photography.
The effective focal length of
a lens depends on whether you
are using a full-size or cropped-
sensor DSLR. Full-size sensor
cameras (with chips the same
size as the old 35mm film) are
more expensive; the sensor is
larger than the Advanced Photo
System type-C (APS-C)
cropped-sensor cameras.
Because the APS-C camera has
This image of the summer Milky Way was shot through a Canon 6D with
a 47mm lens at ISO 3200. The photographer mounted his camera on a
Celestron Advanced VX tracking mount and made a 2-minute exposure.
JOHN CHUMACK
a reduced sensor size, the image
it produces is magnified, thus
reducing your field of view.
Keep that in mind.
Next, let’s take a look at
tracking. A high-quality polar-
aligned mount or go-to plat-
form with accurate tracking is
essential if you want to produce
images without trails.
Accessories are available that
will let you piggyback, or
attach, a camera-lens combina-
tion to a telescope on a mount.
This can be an ideal setup if the
mount is equatorial. The only
drawback to this method is if
you are setting up a scope just
to piggyback a camera, as a lot
of work is involved.
A number of small equato-
rial tracking platforms are
available at reasonable prices.
Each will carry a camera and
lens, or even a small telescope
with a camera attached, but you
will need a sturdy tripod on
which to mount the tracking
platform. Setting up and polar
aligning such a system is usu-
ally easy, and this equipment is
also light, so it’s a joy to trans-
port. For the exposures you’ll
collect, perfect polar alignment
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