Last updated: 20 November 2007
Subject:	etx125
Sent:	Monday, November 19, 2007 00:34:37
From:	mjb mjb (
Without putting too finer a point on it, I have wound the collimation
screws out too far and the  mirror is now loose inside the tube. What
next please ??
Mike here: From our resident hardware expert, Dr. Clay Sherrod:
From:	P. Clay Sherrod ( have made so much adjustments that you have disengaged the
mirror?  If this is the case, then there is absolutely nothing that YOU
should attempt; it needs to go in for repairs.

For those who have never attempted collimation on any closed tube MAK
which must be dismounted from the mount to collimate, simple words: DO
NOT.  To attempt to do so will always lead to even worse collimation or
serious troubles as we have here.

Sorry for this, but you should have written sooner for some collimation
advise OR consulted the articles posted on Mike Weasner's website about
the does and don'ts of collimation of these telescopes.

Dr. Clay
Arkansas Sky Observatories
Harvard MPC/ H43 (Conway)
Harvard MPC/ H41 (Petit Jean Mountain)
Harvard MPC/ H45 (Petit Jean Mtn. South)


thank you for your timely advice. Unfortunately I live on an Island in
the South Pacific that doesn't have a repair service and to send it back
to the States would cost more in freight than the scope cost me..used.
It's either throw it out or let it lie...or try to fix myself. Such
things are not unknown... Thanks
You can access the main mirror and behind it (so that you can re-engage
the three alignment screws) by first taking out the THREE small cap head
screws that are embedded in the holes found on the plastic rear cell of
the OTA; take those out completely.  Once out, take off the focus knob.

Then pull the OTA out the FRONT of the fork will be tight,
but it will come out easily once it breaks free. Once out, then unscrew
the entire BLUE aluminum tubing from the very rear steel metal cell. 
This will expose the mirror, the mirror adjustment screws and everything
that you need to reconnect.

Best of luck.  It is fairly easy, but go slow.

Dr. Clay

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