Last updated: 31 May 2006

This page is for user comments and information specific to the Meade ETX-90RA (originally known as the "ETX Astro"), the ETX-90EC, and the ETX-90AT. Comments on accessories and feedback items appropriate to other ETX 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 and I'll post them. Please use an appropriate Subject Line on your message. Thanks.

Subject:	Putting ETX-90RA on a GO-TO Mount
Sent:	Friday, May 26, 2006 12:41:57
From:	Alison Verbree (
I've read everything I can on your site with respect to the ETX-90RA. 
Of course, some of the info is 4-5 years old and the materials suggested
are not readily available in 2006.  I'm having a really hard time coming
up with a DS-60 or DS-70 , or DSX (as most of the examples use).

Are you able to recommend newer "cheap" Meade setups that can be used to
convert the RA model to a GO-TO scope?

Love your site!!
Mike here: If you can get your hands on any of the current DS or DSX mounts you can do similar things. Of course, it may not be worth the expense and if you want to stick wih the older DS mount solution your best bet is looking for an older DS telescope (eBAY, Telescope Warehouse, etc).
Subject:	Is it possible this information?
Sent:	Saturday, May 20, 2006 06:31:47
From:	Pablo De la Fuente (
Since a lot of weeks I have read about articles of your excellent
webpage, This week I bought a old ETX 90 M and I'm thinking in to do a
project to install a control AZ/DEC, homemade of course and very simple
system but I'd like to find the scheme electronic of port Autostar valid
to ETX90 EC or RA to view and understand like works and what signal it
has and study my project.

I think perhaps you know some link or place where I can found this
information. Your personal web is excellent, thank you very much!
Mike here: See the article "Dick Seymour's Autostar Schematics" for Autostar info and the various cable articles, all on the Helpful Information: Autostar Info page.Also, check out "Steve Bedair's "Go To" Mounts (Autostar info)" on the Autostar Info page. If you do get something developed and you want to share it with others, send me a write up with photos and I will post it.


Thank you again, I'll do it sure.

Pablo de la Fuente

Subject:	RE: ETX 90 - drives too fast
Sent:	Friday, May 12, 2006 00:53:00
From:	Keith Peters (
I will check the Microstar buttons this evening and see if one is stuck.
If it is a problem on the circuit board is there anything I can do to
identify the fault and correct it?

Many thanks for your help.

Most appreciated.


Keith Peters U.K.
Mike here: Hard to say what could be wrong if the problem is on the circuit board. You could contract Scopetronix, who made the Microstar; they no longer make it but should be able to put you in the right direction.


From:	Doug Wayland (
I have been reading posts here for a long time, your site is great.

To the fellow who has an ETX 90RA that drives too fast, I thought I
could add a suggestion. He said it was powered by two 9V batteries.
Normally the 90RA is powered by three AA batteries at 1.5 V each. It
seems to me that the problem is too much power, and the motor is running
way too fast.
Hope this helps,
Doug Wayland Prince George, BC, Canada
Mike here: The Microstar circuit board uses two 9V batteries.
Subject:	ETX 90 - drives too fast
Sent:	Thursday, May 11, 2006 04:19:16
From:	Keith Peters (
I have purchased a second hand ETX 90 RA.   (Runs off two 9v square
batteries).   The drives run far too fast to track an object.   I cannot
see any way to adjust this.   Can you advise?
Many thanks,
Keith Peters (U.K.)
Mike here: Are you sure you have properly aligned it to the Earth's axis?


The drives run so quickly you can actually see the telescope moving.   I
have another Meade telescope which drives well and the movement in RA is
not discernible to the eye?   It is almost as if the RA drives are
receiving too much power from the batteries or a gear is not engaged?  
I cannot see anyway of slowing the drives or calibrating them? The ETX
90 has the old "Microstar 2" handset.

Any advice gratefully accepted.


Keith Peters U.K.
Mike here: Ah ha, it sounds like the Microstar 2 (I have the Scopetronix Microstar II+ on my ETX-90RA) is stuck. Check the buttons; perhaps one is sticking down. If it isn't the button it could be a problem on the circuit board.

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