I was one of the first
people to receive a new Astrotech 8” Ritchey Chrétien
telescope at NEAF 2009. After doing months of research (on a scope
that hadn’t even been released yet) I found there to be mixed
opinions. Many people on the CN Forums were skeptical that a quality,
Ritchey Chrétien could be produced for $1,395.00. Hoping that
such a telescope could be produced at such an affordable price, I
pre-ordered mine for pickup at the telescope show.
Upon my arrival I was
stunned by the appearance of the Telescope. The Carbon Fiber OTA
really gave it a good look. To me this was a key selling point, but I
wanted a scope that could look good and perform well also. While
$1,395.00 is a bargain for a Ritchey Chrétien, it is still a
lot of money; I didn’t want to spend so much money only to get
a mediocre telescope.
When I spoke with the
staff behind the Astronomics booth I was assured that the telescope
was of great quality, and would work very well for Astrophotography.
They had so much confidence in their product that I trusted them and
bought one of the First At8Rc’s. I couldn’t wait to get
it under the stars for the first time.
The box it came in was
light but upon opening it the 8Rc was very securely fit inside.
The telescope itself is
also very light, weighing only around 16 Pounds according to the
Astronomics website. Most mounts could easily carry the 8RC. Another
useful feature are the Dual dovetail bars, one to fit vixen style
mounts, and another to fit Losmandy style mounts. When placed on my
Orion Atlas EQ-G, the Vixen dovetail held the At8Rc and my
guide-scope securely.
The instruction manual
was very easy to understand, and the adapters and spacers fit to the
telescope with ease. Astrotech’s dual speed focuser could
easily bear the load of my Canon DSLR. I’m not sure how much
weight the focuser can actually handle though. My DSLR is pretty
light, and I don’t think that the standard focuser would be
able to accommodate a large format CCD. The newer At8Rc’s
feature an upgraded focuser, which I have little knowledge about.
However, I wish my scope had a sturdier focuser for when im ready to
upgrade to a heavier CCD.
By the time I had
everything mounted and ready to be used, I was very confidant in this
telescopes ability. The only thing I was nervous about was my ability
to collimate it. However to my surprise, my telescope was collimated
very well right out of the box; even after the 80 miles it spent in
the trunk driving the bumpy New York Highways.
Heres
an image showing how well the scope was collimated right out of the
box.
It turns out that the
At8Rc is the easiest scope to collimate I’ve ever owned. To
collimate the scope, all I do is defocus any bright star, turn on the
live view of my DSLR, and turn the secondary mirror adjustment knobs
like stated in the Astrotech manual. Another bonus to this scope is
how well it can hold its collimation. On average I collimate the
scope once a month, and I may lug it in and out of the house 5-10
times before I need to collimate again. This takes a lot of hassle
out of setting up for an imaging run.
Now that I have
discussed some of the physical aspects of the telescope, id like to
go into a little detail on how it had done as an Astrograph.
Starting off using this
scope was a bit of a challenge for me. It took me almost 4 clear
nights to get everything working the way I liked. I had never used an
autoguider before and the focal length of my previous setup was about
1/3 that of the At8Rc. However once that problem was solved, I found
the scope to be a pleasure to use. My Images started getting better
and better. Other than minor guiding issues, my first image from the
new telescope was much sharper than anything else I had done prior.
Upon close examination
the stars in the left corners were not perfect. As I got better and
better at collimating this telescope, star shapes got progressively
better towards the edge of the field as well. I’m happy with
the little amount of coma present in this telescope.
Here is an example
showing the star shapes in all four corners of one of my images.
These examples are 100% corner crops.
Bottom Left
Top Left
Top Right
Bottom Right
Center crop on the Ring
Nebula
So as you can see there
really is very little coma with this scope (no field flattener). The
only coma that is visible with this scope is at the extreme edges of
the frame. In my opinion no Field flattener is needed, though if you
will be posting 100% full resolution images a focal reducer may be a
nice add on.
So in conclusion I am
very happy with my Astrotech Ritchey Chrétien. I’ll be
keeping this telescope for a long time (that is until I can get my
hands on a bigger Astrotech Ritchey Chrétien .)
I have been getting great images through this telescope and I would
recommend it to any Astrophotgrapher. The only drawback is the
focuser. Its fine for DSLR photography, but for CCD an upgraded
focuser may be required. Overall this isn’t a huge problem and
I would highly recommend this telescope.
PS.. If you would like
to take a look at all the images I have taken using the At8Rc Check
out my website. http://sgastrophotography.zenfolio.com/
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