Re: [APML] removing the corrector lens from A Tak Epsilon 130

[Gene Horr <genehorr@texas.net>]

Bobby Middleton wrote:

> The guys at
> Tx Nautical repair have never been into the cell and had no
> answers as to how to take it apart. Anybody on the list know
> about this?

Yeah...but my first reply is don't do it.  The whole cell just
unscrews from the focuser.  The lens elements are held in place
by rings.  You'll need a spanner wrench to unscrew them.  

The problem is that there is a good chance that the spanner
will slip and scratch the lens.  Which is likely why TN won't
touch them.

If you are determined to do it yourself I would find someone
with a lathe with a 4" or larger chuck.  Mount the cell in
the chuck (make sure you don't mess up the outer threads!)
Bolt the spanner in place, disengage the clutch, and turn
the chuck by hand to loosen the lockdown ring.  Once loose
then remove the cell, place it face up on a work surface, 
and use Q-tips to unscrew the lock down ring.  IIR this
is a triplet design, so you will have to remove 3 rings 
to get to all of the surfaces.  Be sure and mark the location
of the second ring to be able and reassemble it correctly.

Something to keep in mind is that you will get dust and
other particles on the inner surfaces of the lenses, another
reason why TN won't disassemble them.

BTW - would masking down before the corrector allow you to
test whether or not coating the edges would help?

Gene Horr
genehorr@texas.net

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