iOPTRON - Astronomy Technology Today

The Rigel Systems
USB nSTEP and
AstroSystems
Collimation Tools
Two Keys to Successful Imaging
with a Fast Newtonian
By Austin Grant
When I started looking for my first
“serious” telescope for astrophotography, I
knew that the decision would come down
to several tradeoffs. While the precisioncrafted
optical masterpieces from the likes
of Astro Physics or TEC would’ve been my
first choice, my tradeoff simply couldn’t be
my car. No, I decided to go for one of the
relatively inexpensive imaging
Newtonians. The money I saved was nice,
but this setup didn’t leave me without
plenty of hurdles to overcome.
Imaging with a Newtonian has some
basic requirements that must be met, and
when the focal ratio is f/4, those requirements
are significantly more stringent.
First, a coma corrector is required. I used a
Baader MPCC, and it works great. Check
that off the list! Then, collimation must be
spot on. Finally, perfect focus is the only
way to get pinpoint stars. To get the most
out of my scope, I use collimation products
from AstroSystems, and I focus my
telescope with a Rigel Systems USB
nSTEP Stepper controller and motor.
AstroSystems
LightPipe/SightTube
and Autocollimator
I initially thought that proper collimation
alone would be all I needed to create
sharp astrophotos with my telescope. Even
more naively, I’d hoped that the collimation
cap included with the scope would do
the job. I remember the laughs from one
of our club members when I started collimating
my scope for the first time. Turns
out he wasn’t laughing at my tools or
technique, but simply because, “those
scopes come collimated from the factory.”
It was a silly comment then, and was one
of the reasons I’ve now decided to write
this article.
Many of us in this hobby assume that
gear comes from the factory ready to use.
While this may be the case for most of it,
it’s simply impossible for Newtonians and
other non-fixed optic designs. If the optics
aren’t properly aligned, the images produced
won’t be representative of what the
scope can deliver. Furthermore, a simple
collimation cap isn’t the best option, particularly
at f/4! Fast focal ratios are great for
minimizing image-integration times, but
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