Last updated: 30 April 2001

This page is for user comments and information specific to the Meade ETX-90RA (originally known as the "ETX Astro") and the ETX-90EC. 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:	Question Regarding ETX-90 & power supply
Sent:	Sunday, April 29, 2001 16:00:57
From:	bryangm@excite.com (Bryan Morris)
You guys have helped me in the past to get my ETX90 running smooth. 
Everything works great, though recently I've decided to quit using
batteries and instead use an external power supply.  Being a collector
of all kinds of electronic gadgets, I found what I believe to be an
acceptable power supply from "The Closet O' Stuff" (of the Black Hole as
my wife calls it).   Its a wall-wart from an old scanner.  Its 15v,
1.0A, 15W max.  It seems to work fine and the motors seem to work


... I can use the Autostar to find and start tracking an object... for a
few minutes.  Then all of a sudden the Autostar doesn't seem to like
where its at and will rise about 20 degrees and start tracking...  I can
start from the home position (I use alt/az mode) and recalibrate and it
will work fine for a little while and then flake out again...

I haven't switched back to batteries and can probably find anothing
wall-wart laying around... but the specs for the one I'm currently using
should work right?  Please let me know.

Thank you

Mike here: This sounds like the random slew problem that some ETX-125EC scopes have experienced. You might want to contact Meade (see the Meade Announcements on the site home page). Of course, you'll want to tell them that you are using an unsupported AC power source. That might have a bearing.

Subject:	ETX90 Best Buy
Sent:	Friday, April 27, 2001 14:58:45
From:	snyderld@yahoo.com (Dan and Lynn Snyder)
I've read you site from time to time for a couple of years now, and I
must say, that like the energizer bunny you "just keep on going and
going" . Keep up the great work!

Say,  I think I git a pretty nice deal at the local Natural Wonders
store (just going out of business here).

I bought the ETX90 for 20% off the sticker price, and they threw in the
883 tripod for a mere penny.

Everything seems to work fine - especially the optics, and last night I
upgraded the autostar from 2.0g to 2.1ek successfully.

Anyways, It's nice to have your site around.

Dan Snyder, Seattle

Subject:	ETX-90
Sent:	Thursday, April 26, 2001 19:31:33
From:	mlcunningham99@hotmail.com (Lynn Cunningham)
My name is Lynn and I purchased a ETX-90 at Natural Wonders about a year
ago for my boyfriend.  We haven't used it much until recently (Northeast
was quite cold this winter) but I just want to see if we have a problem.
The motor is quite loud and seems to stay on in slow mow for about a
minute after we've found our object.  Is this a focuser, a motor defect,
or %$^@? The loud motor seems to take away from the joy of being
outdoors in the middle of nowhere looking at the stars..  Do you have
any thought, or have you heard of this before?

Thanks so much.


PS) I'd love to join the ETX gang for a party!!
Mike here: Well, I need some more info but at first guess I would suspect you are hearing the Right Ascension drive running. It shouldn't be loud however so this may not be what you hear nor the motion you are describing. So, can you be more explicit: What model ETX-90 do you have? Do you have the Autostar? What mode (polar or alt/az) are you using the ETX in? You mention a "focuser"; do you have one (although if that was running you would see the effect by looking at an object in the eyepiece). Anyway, need more info.


Wow - I didn't think anybody responded that quick!!  We have an ETX-90EC
Astrotelescope with an Autostar.  I do not know what you mean by the
mode. We do not have a focuser.  The sound is not necessarily loud but
always running.  It's a little bit lighter than the sound the motor
makes when moving to another object.  Once it gets to the object the
autostar says it slueing and the telescope has other little motors
running, then you hear the beep that says, "there it is."  Then the
motor continues to run sporatically while observing.  This is not too
loud but still running persae.  Any thought? Is this normal?

Thanks again.
Mike here: Sorry for the delay in responding this time. I was gone all day and night on Friday. The sound you hear is normal. That is the drives running to move the telescope to compensate for the Earth's rotation.

Subject:	ETX90 manual focus
Sent:	Monday, April 23, 2001 16:12:49
From:	Gene_rozea@prodigy.net (Gene Rozea)
I hope this neophytes question isn't too much of a bother -
I just purchased a ETX90 EC form Natural Wonders, who are going out of
business and heavily discounting their inventory. For example the scope,
field tripod and Autostar came in under $470!! So what else could I do?
The bad news is that no exchanges are allowed and there is a problem
with the focus control. It's severely binding as if there is a
misalignment of the shaft with the hole/bushing in the casing. I suspect
that if I loosen the hardware (three hex head screws in back) and
possibly the side mounting I should be able at least to try to find an
alignment that allows a smoother operation of the focus control. I have
no insight into the construction of the scope and sure don't want to
risk misaligning the optics. I have all the tools and am comfortable
using them - been an engineer and tinkerer for 40+ years.
Any advice - or should I get ready to pack it off to the Meade folks?
Thanks for any advice -
Mike here: Sorry to hear about the binding. Haven't heard of that before. If you want to try to see what might be happening, check the photos on "Doc Greiner's ETX Info site" (linked from the Telescope Tech Tips page). I'd be curious to hear what you find.

Subject:	ETX RA 90
Sent:	Saturday, April 21, 2001 14:16:27
From:	rroberts@kts.bssd.org (Randy Roberts)
I hear about all of the "fixes" people do to their ETX's, but up until
now I never needed any.  I have an early ETX and it has not suffered the
problems that many seem to have.  My mirror cell broke shortly after I
got it and Meade fixed it under warranty.  Other than that  it's fine. 
The images are too dim, the optics are good, but not great.  I don't
have any abborations, just a slightly rough polish on my mirror.  I've
still never found a finder I truely appreciate for the scope, but I've
got solutions I can live with.  What has started happening is play in my
dec axis.  The so called altitude rocking.  My problem is slop in the
manual dec control. The rod and knobs actually move back and forth
causing the play.  I'm not sure how to pull those knobs and take that
apart or how to fix it once I get it apart. There are no set screws on
the knobs.  I don't know if they are press fit or threaded.  Any ideas?
Mike here: Have a look at the pages that are linked from "ETX Hints, Tips, Projects, & Products" on the Telescope Tech Tips. I think you'll find what you are looking for there.

Subject:	Meade ETX Hard Case
Sent:	Thursday, April 12, 2001 19:26:08
From:	nicnrick@mediaone.net (Rick and Nicole Happoldt)
I picked up a Meade Hard Case for the 90EC, and now I am hearing that I
can't install the right angle finder and use this case!  Do you know if
this is true?  I have heard that some people have gotten it to fit if
they mount the right angle finder at a 45 degree angle.

Any thoughts?

Mike here: I've heard this. You might be able to cut out an area for the finderscope to fit. As to mounting the finderscope 45 outward, I'd do that anyway to avoid fogging it over while looking through the ETX eyepiece.

Subject:	Re: ETX 90EC Question
Sent:	Wednesday, April 11, 2001 20:39:46
From:	nicnrick@mediaone.net (Rick and Nicole Happoldt)
I called Meade today and spoke to a different customer service person to
explain my problem and insist on having Meade fix it.  However, to my
surprise, the rep (his name is Ossie) seemed genuinely concerned and
agreed that the scope should not exhibit these problems.  So, I am
sending the scope to Meade to correct these problems!

He also said that the "Made in Mexico" sticker was not just for scopes
sold outside the US, which explains how I got one.

Anyway, it doesn't matter to me as long as they fix the problems so I
can start enjoying my scope!

Thanks again for all of your help,


Subject:	ETX 90EC Question
Sent:	Tuesday, April 10, 2001 19:50:59
From:	nicnrick@mediaone.net (Rick and Nicole Happoldt)
To:	sherrodc@ipa.net
Clay and Mike,

I have been reading all the comments on the ETX 90EC mechanical
tolerances and the ways to correct it, but since this is a brand new
scope, I wanted to check it out closely and make adjustments to the
Autostar to compensate for any gear backlash first.

Since this is a brand new 2 day old ETX 90EC with Autostar, I don't want
to rip into it if it's actually OK.  I have also updated to the latest
bios, rest the Autostar, calibrated the motors, trained the drive on
both axis, and set the backlash compensation.

I have noticed a couple of things that I am trying to determine if they
are "normal and acceptable".

1.  When using the standard hand controller, the RA movement is delayed
by 1 second when changing directions.  Is this normal and acceptable?  I
have compensated for it with the Autostar using 60%.  Any more and the
image jumps, any less and there is a delay in movement at speed 2.  Is
this considered normal and acceptable?

2.  When I am slewing to center my object at the slower speeds, the
movement starts slowly, picks up a little speed, then even after I
release the button it kind of "settles" with slight continued movement. 
Also normal and acceptable?

3.  The DEC axis has this, but to a much lesser degree (compensating
with the Autostar at 35%).

4.  If either DEC or RA axis clamped down, I can move the scope slightly
on either axis, suggesting the worm gears may have play in them as well.
Is this also considered normal and acceptable?

I am hesitant to send the scope back to Meade if all they are going to
do is say "Yeah, that's normal and won't affect goto accuracy", but you
actually use these scopes, so I value your non-biased opinon.  I am also
hesitant to crack the scope open to adjust during the warranty period.

Thanks in advance for your help,

From:	sherrodc@ipa.net (Clay Sherrod)
Rick - what you describe is not normal, but does unfortunately occur in
many GO TO scopes.  The play you describe by rocking in both axes can
be:  1) lack of gear loading; 2) gear mount looseness; 3) worm gear out
of adjustment; 4) play in the DEc (altitude) trunions where they pass
through the fork arms, and many things.

You have your percent compensations set WAY to high; I would do a
complete reset and then train at VERY high power on an elevated
stationary object; if you are observing in Alt-Az, wait until dark and
use Polaris.  Training is the MOST IMPORTANT step is success of your ETX
and will take a LOT of play out of the drives as long as they are on and
moving (when the scope is turned off, expect more play than usual.

I think that if you will back your percentages down to Altitude = 09%
and Azimuth - 17% and then RETRAIN VERY SLOWLY AND PRECISELY at high
magnification, you will see a lot of problems eliminated, particularly
the creeping after a slow slew.  Some of the lag in response time will
also be eliminated.  By the way, what speed setting is giving you the
1-second delay?  That would not be all bad below "5", but unacceptable
at "5" and above.

Give us more details and maybe we can keep your frustration at a
minimum.  At this point, if under warranty, Meade will fix ALL your
mechanical woes (you have to be specific to them as to what they are)
for free with about a three week delay at the plant.

Good luck!        Clay Sherrod
Mike here: I should point out that some play (2-3 degrees) is normal in both axes when moving the tube by hand when they are properly locked. This is true for the factory configuration and is normal. It can be improved but I would recommend against it on this new scope until you see if it really bothers you and affects operation.



Using speed 9 I get a delay of what looks like about one second, maybe a
little less.  I called Meade and they said that 2 seconds at speed 9 in
within limits.  I have an LX200, which has no detectable backlash in
either axis, so I admittedly spoiled.  Anyway, is this the correct order
in which to perform a training:

1. Reset and initialize
2. Program scope information
3. Calibrate motors
4. Train drive
5. Set ALT and AZ compensation percentages?

It occurs to me that I may be setting my percentages too high as I am
merely pointing the scope at a street light down the street for all of
my training.  This is likely not accurate.  I was trying to get a ball
park estimationg of my scope, and I may be shooting myself in the foot.

What causes the creep after slew, anyway?

Anyhow, just steer me in the right direction for training my drives and
I will retry it.  The only eyepiece I have that's 1 1/4 is the 26mm
Plossl, but I do have a 2X barlow (all my LX200 eyepieces are Nagler and
Panoptic 2" eyepieces.  Some have 1 1/4 barrels, but I am not sure if
they would cause more harm in training the drive than good due to their
weight), so I will use the barlow and get 13mm for the training.

Thanks VERY MUCH for all of your patience and advice!  I am just trying
to determine if this scope is in fact acceptable or if I need to ship it
to Meade (I hesitate to crack it open since it is so new and under


OK, if the RA axis is locked and I move the RA axis by hand, it moves
(reluctantly) almost 1 degree.  The DEC axis is about the same.

So, in the RA axis at speed 9 with the hand controller (not Autostar), I
get a little less than or about equal to one second response when
chaging directions (hard to time this).  Also, I need to clamp RA a
little past the half way point to fully engage the clutch.

How does this sound to you?

Mike here again: Sounds pretty much as expected from what I've seen. I have not attempted to do any tuneups suggested by Clay (the ETX-125EC is a loaner from Meade). By the way, does your standard controller have 4 or 9 speeds? Mine has only 4.


The standard controller only has 4 speeds, but it appears to me that the
fastest speed corresponds to speed 9 on the Autostar (haven't timed it,
but it appears that the fastest speeds are identical).

I printed out Clay's tuneup guide, and it seems to me that it might be
possible to get this thing sitting pretty if I simply perform all of the
Autostar electronic steps.  Since he did his test with the three
Autostars, it appears that the scope is much less of a factor than the
drive training and backlash compensation.


Mike here: Thanks for the clarification on the speed; I thought maybe there was a new model standard handcontroller! And yep, drive training and the compensation are important to fine-tuning the system.


From:	sherrodc@ipa.net (Clay Sherrod)
Rick - from all your messages, you sound like a guy who has a defective
scope.  I would not accept "2 seconds" of delay as my fastest speed, nor
would I accept a full degree of slop in both axes.  How are you setting
the alt and az percents if you DO NOT have an AutoStar?????  This is
strictly an AutoStar v2.1 (latest) function which is not even common to
the most recently shipped ETX scopes.  I am really puzzled by that.

They play is what concerns me....as well as the reference to setting
your percentages.  Please clarify.  ALSO, do not train level as you are
doing...take the time to put it up outside and aim it at Polaris to tilt
the scope upward; this torques the motors....TRAINING IS VERY IMPORTANT,
BUT......why are you training if you are using you standard Hand
Controller?  The standard controller does NOT recognize the motor
training....only the AutoStar.  There is some talk out there that if you
train with an AutoStar and then use your standard paddle, you will have
to train the A.S. all over again for accuracy.

By the way, the 1 degree slop in DEC is very common for the ETX 125 and
part of what the Supercharge tune up corrects....it is VERY difficult to
remedy.  Be very careful to NOT overtighten either axis.  I still
hesitate to tell you to get into the scope...it sounds like you have a
COMBINATION of problems.

Please explain to us this "standard hand controller reference" when all
of the training, tests, percentage, etc. MUST be in compliance with the
AutoStar, not the standard unit....

thanks and good luck....keep us informed so that we can work through
this with you.

Clay Sherrod
OK, I have a delay in RA < or = 1 second at the fastest slew speed. 
Does this sound fairly normal and will it affect goto accuracy?

If not, would you recommend sending the scope back to Meade, or would it
do any good?


Mike here: I suspect that Meade will tell you it is in spec.

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