Sky & Telescope - December 2021 - 3

At last! A new, expanded and updated edition of
THE BACKYARD
ASTRONOMER'S
GUIDE
This fourth edition, by Terence Dickinson
and Alan Dyer, expands the go-to guide for
experienced amateur astronomers. It sets a
new standard for astronomy guides.
The book is completely revised to describe
the latest technology, observing techniques
and equipment.
KEEP IT SIMPLE
Keep clutter to a
minimum. Cables snag,
and connectors break.
The more you have,
the more that can and
will go wrong.
TEST SHOOTING
The same deep sky setup we recommend in " A Good
Starter System " (page 364) is here at work taking images
of M31, the Andromeda Galaxy (see photo on page 365).
CHOOSING
DEEP SKY GEAR
N
ow we start spending! To keep costs
reasonable, we concentrate on fitting
you out with a good entry-level deep sky
rig for less than $3,000. So this is not a shopping
list for advanced users seeking a dream
" retirement " system.
OUR FIRST-CHOICE TELESCOPE
We feel that the best telescope for starting out
in deep sky photography is an apochromatic
refractor with about 80mm aperture and an
f/ratio of f/5 to f/7. Prices start at $1,000 for the
optical tube.
The advantages are many: The speed is fast
enough to keep exposures short while providing
an evenly illuminated field with corner-tocorner
sharpness; the tube is small and light,
so it matches well with a small mount for
portability and affordability; and the short
focal length is forgiving of less-than-perfect
polar alignment and auto-guiding.
Yet the telescope's focal length of 400mm
to 560mm is enough for impressive close-ups
of the larger classes of deep sky objects: nebulas,
open star clusters and big galaxies, like
Andromeda and the Magellanic Clouds. What
it can not do well is resolve small deep sky
objects, such as most planetary nebulas, globular
star clusters and galaxies. Those require a
focal length of 800mm to 2,000mm.
GOING SMALLER: ASTROGRAPHS
A class of instrument popular in recent years
is the astrograph. Many astrographs are refractors
with only 50mm to 70mm apertures. That
sounds small, but what distinguishes astrographs
is that they are not designed to be
used visually. Think of astrographs in this size
as first-class lenses with more precise focusing
mech a nisms and sharper optics than a
BEGINNER RIG
Here's another good entrylevel
rig, one author Dyer
used to take the M31 image
on page 343: Celestron's
AVX mount and Orion's
ED80T refractor, with a
StarShoot auto-guider. In
small apos, we can also
choose from APM, AstroTech,
Explore Scientific,
iOptron, Lunt, Omegon,
SharpStar, Sky-Watcher,
Starwave, Stellarvue and
William Optics.
COMPACT
ASTROGRAPHS
The William Optics 51mm
f/5 RedCat (top; $750)
offers precise focusing
and camera rotation.
Another superb
performer is Meade's
70mm f/5 Astrograph
(bottom; $1,200).
Similar small
astrographs are
available from Askar/
SharpStar, Borg/Astro
Hutech and OPT/Radian.
CHAPTER 17 | PHOTOGRAPHING THE SKY 359
Illustrated with all-new photos and star charts,
there are 5 new chapters including binocular,
telescope and Moon tours by Ken Hewitt-White.
THE BACKYARD ASTRONOMER'S GUIDE will
reward you every day of your observing life.
416 pages in full color · hardcover $49.95
And also available in October:
2022 NIGHT SKY ALMANAC
by the Royal Astronomical Society of Canada
A portable guide to the night sky objects and events.
120 pages in color · paperback $14.95
Published by
WHEREVER ASTRONOMY
BOOKS ARE SOLD
www.fi refl ybooks.com
http://www.fireflybooks.com
Sky & Telescope - December 2021

Table of Contents for the Digital Edition of Sky & Telescope - December 2021
