REccomend a new focuer?

I have a Celestron C8-N and the focuser is really bad.
Image shift, sticks etc... can anyone reccomend an aftermarket focuser?

Paul

I have a Celestron C8-N and the focuser is really bad.
Image shift, sticks etc... can anyone reccomend an aftermarket focuser?

HI Paul:

Image shift is one thing. You can expect a small amount of focus shift--maybe
45" or less--with current Celestron OTAs. And this can often be improved by
running the mirror through its travel a couple of times.

But sticking? Uh-uh. That ain't right. I suggest a call to Celestron. Something
is wrong...w-r-o-n-g.

Even if you get an "aftermarket focuser"--a crayford, that is--you will still
need to use the main focus, as the travel of a crayford is not NEARLY enough to
acommodate differing eyepieces, cameras, etc.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html

On 18 Sep 2003 20:22:26 GMT, (Rod Mollise) wrote:

Even if you get an "aftermarket focuser"--a crayford, that is--you will still
need to use the main focus, as the travel of a crayford is not NEARLY enough to
acommodate differing eyepieces, cameras, etc.

But the Clement focuser *does* have all the travel you need. Except
for the fact that a SCTs SA is degraded at the extreme primary
positions, you could screw the standard focuser all the way CW, lock
the mirror, and do all future focusing with the Clement. Freakin'
amazing!

Wayne Hoffman
33° 49" 17' N 117° 56" 41' W
"Don't Look Down"

http://home.pacbell.net/w6wlr/

The C8-N is a newtonian, not a SCT,
so there is only one focuser.

With a high magnification the focus is not nearly fine enough for my satisfaction in any case.

Paul

With a high magnification the focus is not nearly fine enough for my
satisfaction in any case.

Paul


Hi Paul:

Missed the "N"...sorry.

I do have this OTA as well. I wasn't very happy with mine, either. What I did,
however, was disassemble it, clean off the "glue-grease," lubricate it with
white lithium grease, and reassemble. Once it was back together, I adjuted the
two small allen screws (on the top, near the locking screw) until I was
satisfied with its action. You could replace it, there are any number of good
Newt focusers out there. But, remember, you'll need to choose one of similar
racked-in height or you'll have to perform major surgery on the OTA.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html

I do have this OTA as well. I wasn't very happy with mine, either. What I
did,
however, was disassemble it, clean off the "glue-grease,

Rod: Just what solvent did you use on the "glue grease?" I have done this a
few times and never been quite satisfied that the glue was all gone..

Jon

Rod: Just what solvent did you use on the "glue grease?" I have done this a
few times and never been quite satisfied that the glue was all gone..

Hi Jon:

Mineral spirits, as recommended by ATM extrordinaire, Pat Rochford.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html