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Last updated: 30 November 2012

This page is for user comments and information specific to the Meade ETX-90RA (originally known as the "ETX Astro"). Comments on accessories and feedback items appropriate to other ETX, DSX, and DS models are posted on other pages. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me for posting. Please use an appropriate Subject Line on your message per the Site Email Etiquette. Thanks. Remember, tips described on this site may invalidate the warranty on your telescope or accessories. Neither the submitter nor myself are responsible for any damage caused by using any contributed tips.

Subject:	Re: Can ETX90-RA voltage regulator survive 5 volts input rather than 4.5
Sent:	Friday, November 30, 2012 03:41:25
From:	Mike Corley (
I am not sure you remember my situation, but you asked me to let you
know how it worked out.  I have finished my project for this scope and
thought you might be interested in what has been done.  I can't claim
credit for the original idea, juyat for my implementation of it.

I installed a stereo 1/4" jack on the side of the case.  The ground and
left channel I wired to the ends of the original battery holder.  The
right channel I wired directly to the positive pole of the RA motor.  I
then build in a small plastic case a 5 volt power supply and three
switches. Switch 1 is power on/off to the telescope (keep in mind I left
the switch on the bottom of the telescope in the ON position).  The
power wire flows from switch through a momentary switch that is normally
closed, from there to the left channel side of a 1/4" stereo plug.  A
seperate 5 volt wire goes to switch 3 that is a momentary contact switch
that is normally open, from there to the right side of the stereo plug.

Here is how it all works.  The ground and left side of the stereo
circuit feeds 5 volts to the internal power supply in the scope.  The
original voltage was 4.5 volts from three AA batteries, so I don't think
a half volt overvoltage is going to hurt it much.  When the power is
turned on via switch one, the telescope works normally.  The momentary
contact switch #2 allows me to interupt the voltage and stop the motor
for a brief moment or two if the scope is a little ahead of where it
should be.  Switch three however feed a full 5 volts directly to the
motor, speeding it up considerably shoild the scope be a little behind
where it should be.  This little control box gives me the ability to
tuen the scope on and off without taking it off the tripod (a flaw in
the original design) and allows me to adjust the position of the scope
in turms of RA.  Overall a very usefull and acceptable outcome, if I do
say so myself.  If you would like, I could take some pictures and
forward them to you.

I want to thank you for all the work you have put into your web site.  I
have been in the computer business since 1968, so I have an appreciation
of the level of commitment it takes to create what you have.  I am sure
better persons than I have said so, but none as honestly appreciative.

Subject:	etx 90ra collimation...
Sent:	Sunday, November 25, 2012 10:35:06
From: (
Glad to see the sight still plugging along!
I just wanted to send you a note that last night, I split Rigel with a
16mm Celestron erfle...
After 12 years of ownership, I still haven't had to collimate!
BTW, any comments concerning the NEW ETX-90?
Best regards,
Chris Brown
Irvine, CA.
Mike here: Thanks! Glad the ETX is still doing great. No experience with the new ETX-90 but it is the same optics.


Cool, Mike!
BTW, I was showing my daughters' friends Rigels' companion star, I said,
"it's at 7:00 o'clock...but they don't know what that phrase means...
Chris Brown
Irvine, CA.
Mike here: Yep, we need to start using angles (ie, 210) instead of analog clock positions and even "clockwise" when referring to rotation.

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