Wyoroc Premium 2" Crayford Design Focuser
Tom Nicolaides
February 2, 2006
Not long ago I purchased a
Hardin 12 inch F5 Dobsonian. The
idea was to get some eyepiece time in while my imaging rig was taking two or
three hours worth of frames. The
dob came with a fairly nice crayford – I see it sold by itself under various
names, but I believe it to be made by GSO. The problem was that it could not come to focus – not enough
in-travel- with one of my favorite eyepieces, nor would it come to focus with
my DSLR at prime focus.
I had the same problem with my
Konus 8 inch Newtonian. I solved
that problem with a JMI crayford.
But then I saw this web page by a company called Wyoroc:
http://home.comcast.net/~wyorock/wyorock.html
I could tell from the photo that the height was a lot less
than the Hardin crayford. The
price wasn’t bad, so even though I’d never heard of them, I ordered one with an
adapter plate milled to match the outer surface of my OTA. Total cost, shipped, was 135 USD.
It arrived in only three days, being shipped Priority
Mail. The first thing I noticed
was the finish – bare machined aluminum.
It *looks* like a piece of custom precision machinery. Operation of the focuser felt
smooth. There was no change in
turning resistance when racking out or racking in. Total travel is 2 inches. Tension is adusted by a single set screw under the focuser
shaft. Next to that is a plastic
locking bolt.
I experimented with the tension adjustment, but ended up
coming back to the factory preset.
At this tension it cam easily hold my DSLR (a canon 300D) and stay where
I put it even without locking the drawtube. And focus action is still quite smooth.
The focuser consists of the focuser body, drawtube, focusing
shaft & knobs, adapter plate, and jam ring. The adapter plate is mounted to the OTA with four flathead
screws (not supplied). The focuser
body threads onto the adapter ring.
A jam ring holds it in position one the desired focuser clocking is
achieved. There are no provisions
for collimation, so make sure you drill your holes accurately! In fairness, there are no collimation
provisions in the Hardin focuser either.
I did have to drill new holds in my dob, as the Hardin hole
pattern does not match the Wyoroc adapter plate. Be careful when you do this to get it right – There are no
collimation provisions.
After I received the focuser I contacted Wyoroc and asked
about it. I was curious if they
manufactured it or if it was an import.
Caroline from Wyoroc wrote back to tell me that they do manufacture the
focuser with their own computer controlled milling equipment in Utah. She told me that most of their work has
been government contracts and they hoped to gain a foothold in the amateur
market. I also asked about the bare
aluminum finish. She told me that
was in response to customer requests, but they do have a few in inventory that
are anodized – see my impressions, below.
Impressions:
This is a fine-looking piece of machinery. Fit and finish are as good as anything I’ve seen. The bare aluminum does give me some
cause for concern, as even aluminum will oxidize. I’m giving some thought to disassembling it and applying an
alodine process to it. While not
as good as anodizing, it does provide corrosion protection and it gives a nice
golden color. The action isn’t as
smooth as some crayfords I’ve used, but those have all been much more expensive
– The Moonlite and William Optics gear reduced crayfords are better, for example. However, it is better than both of the
Hardin crayfords I’ve owned and it’s a bit better than the JMI NGF I have on my
Konus. Finally, it looks REALLY
cool!
