AT SOME POINT in an amateur astrophotographer’s journey,
you reach a plateau. You may find that you’ve imaged most
common targets, perfected processing techniques, and mastered
your equipment. Unless you’re willing to travel to a different
hemisphere, everything begins to feel like a familiar old friend
compared with the excitement of a brand new relationship.
Some of us find new energy by pur-
chasing a longer focal length scope to
image smaller targets, only to discover
unexpected challenges due to poor see-
ing, imperfect collimation, and the need
for off-axis guiding, not to mention lim-
ited portability.
Others go in the direction of forgoing
amateur equipment entirely and instead
processing data captured by professional
astronomers using ground-based obser-
vatories or space telescopes. Still others
have gone to wider fields of view (FOV),
using large CCD chips like the KAF-
16803, along with a high-quality apo-
chromatic telescope.
This is the approach I’ve taken in my
evolution as an amateur astrophotogra-
pher over the past two decades, in order
to gain a greater appreciation of target
size — especially when it comes to large,
sprawling nebulae.
In recent years, I’ve enjoyed using
a Takahashi FSQ-106 apochromatic
refractor, which has a focal length of
530mm and yields a respectable field of
view of 4° at image scales in the rangeof 3.5" per pixel. But, recently, I’ve
pushed things even further to capture
very wide-field views of nebulae and
star fields in the Milky Way. I’ve taken
a hybrid approach, employing an even
wider field of view obtained using an
inexpensive, high-quality Pentax lens
as a canvas upon which to repurpose
some of my prior, higher resolution
images. I’ve found that this offers a
new perspective on familiar targets by
showing how they relate to one another
in the night sky.Choosing equipment
In order to obtain a very wide-field
backdrop, I decided to couple my
Apogee Alta U16M CCD camera (which
has a KAF-16803 chip) with a Pentax 67,
200mm fixed-focal-length lens that I
obtained at a great price from eBay a
few years ago. This afforded me a very
wide field of view of almost 11 square
degrees, while still maintaining a rea-
sonable image scale (9.27" per pixel).
I also take advantage of a high-
quality CCD camera and filter wheelWWW.ASTRONOMY.COM 53
The author’s wide-field imaging setup employs a Pentax 67 200mm lens, coupled with an Apogee Alta
U16M CCD camera, with a filter wheel attached.The author’s technique
produced a beautiful wide-
field image of the supernova
remnant Simeis 147 (lower
right, sometimes called the
Spaghetti Nebula), and the
region of nebulosity in
Auriga that includes IC 405
and IC 410 (near top left).