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Last updated: 31 July 2012

This page is for comments and user feedback about ETX telescopes. ETX models discussed on this page include the ETX-60/70/80/90/105/125 (EC, AT, BB, Premier Edition). This page also includes comments and feedback of a general nature. Comments on accessories and feedback items appropriate to the ETX-90RA, 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.

Sent:	Sunday, July 29, 2012 03:07:57
From:	BF (
Thanks Mike. Glad to see everything is still going strong.

Sent:	Friday, July 27, 2012 01:44:14
From:	BF (
Hello, trying to get back into astronomy after a small absence.  My
scope, although functioning, requires a replacement declination
worm-gear assembly.

In particular, the bracket has broken.  I think Meade varied these
through the years but my bracket is about 55mm long.  Any assistance
would be appreciated.
Bill Farmakidis
Sydney, Australia
Mike here: See the article "Replacement Gears source" as well as several articles on gearbox repair on the Helpful Information: Telescope Tech Tips page.

Subject:	Difference in optics between ETX and LS, LT series?
Sent:	Wednesday, July 25, 2012 05:11:59
From:	Jorge Mancillas (
Thank you so much for your website. It is a really valuable resource.
I want to ask  you what I  hope is a very simple question, which is: are
there significant differences in optics between the ETX and the LS or LT
series, or is the difference only related to the mount, computer
assistance location of objects and the like?
I am thinking of buying one of the ETX 125 still available in the market
(here in Europe, in fact. I live in France). But I am wondering if I
should spend the extra money on an LS or LT.
Also, I am assuming that if the discontinuing of the ETX 125 by Meade
proves permanent, I will not experience many problems, but it seems
still worth getting the 125 over the ETX 90.
Any opinion would be welcome.
Thanks again.
Mike here: The main differences in the optical designs are Maksutov-Cassegrain (ETX) vs Advanced Coma-Free or Schmidt-Cassegrain (LS, LT), and the aperture size and focal length (resulting in different f/ ratios). Whether these differences will be significant to you will depend on how you want to use the telescope and on your expectations.

Subject:	ETX 125 on Brasil
Sent:	Tuesday, July 24, 2012 15:26:07
From:	Edson Sena Jr. (
It is a great pleasure to contact you, Congratulations for your site.

I'm from Brazil and recently managed to acquire one with many obstacles
a meade etx 125.

but for lack of experience I have caused damage to the set that supports
the gears which makes the horizontal movement. (Please see photo

Unfortunately it is impossible to get assistance in the region that I
am. So I'm doing the repair on my etx by myself.

I want to know how can I get to buy the damaged part.

I am completely grateful for your help.

Edson Sena.


Mike here: You may be able to purchase a replacement gearbox from Telescope Warehouse (link on the Astronomy Links page). Alternatively, you can try the replacement gear sources mentioned on the Helpful Information: Telescope Tech Tips page. Also, there are several "gearbox" repair articles on the Telescope Tech Tips page.

Mike here: Further down this page is a discussion of some problems with an ETX-105. Apparently, that ETX mount is now for sale. Just FYI. Here's the URL:

Subject:	Etx Website questions.
Sent:	Friday, July 20, 2012 11:50:43
From:	Dave R (
I have gone thru your site quite a bit and think it's great, answered a
lot of my questions. I have admired this scope, and surprised it has a
huge cult following even though it's older. I just got a ETX125-PE on
Ebay and waiting for delivery from someone who clearly took care of it. 

I did have questions if I could. 

1) Dew Shield: Havent had much luck finding one, looks like the "PE"
uses a different style than the "EC", any suggestions..? 

2) When eyeing the Celestron they sell a 5megapixel ccd camera/software
with standard 1.25" opening for approx 200$. Meade no longer makes them,
and hard to find any if they do, the few of them were missing this or
that. Any suggestions for something similar, within the price range, I'm
hoping they arent specific to the vendor..? I want to watch/save photos
on my computer..?

Any other input you have for an ETX-newbie would be great. 
Mike here: Glad you like the ETX Site. Check the Site Guide; it will help you find info on the Site. See the Helpful Information: Telescope Tech Tips page for articles on making a dew shield. They are easily made at little to no cost. As to imagers, see the Helpful Information: Astrophotography page.

Subject:	ETX-90 outside circumference
Sent:	Thursday, July 19, 2012 16:31:28
From:	josh wilson (
I have the newest model of the ETX-90 and I want to make a dew shield
for it. I have all the supplies for it and I am completely ready to make
it except for one crucial item---the telescope. I had to get a
replacement for my scope because the internal RA/Az motor broke. I have
done a little searching and I can't find a site that definitively gives
the outside circumference of the OTA. MY question is simple-- What is
the outside circumference of the ETX-90 OTA? I own the newest (2012)
Mike here: There are many articles on making a dew shield on the Helpful Information: Telescope Tech Tips page. Most don't need a precise measurement of the OTA. I just measured my ETX-90RA (from 1996) OTA and get 328mm.

Subject:	re: ETX 105
Sent:	Tuesday, July 17, 2012 10:11:20
From:	richard seymour (
Rather than "excessively tighten" the DEC knob, you might try opening
that cover and inspecting/removing any excess grease on the clutching
They might be making it too "slippy", hence requiring the excessive force.

You could also take the opportunity to carefully inspect the center
shaft (which the knob tightens into) to verify that the plastic isn't

good luck

Subject:	ETX 105 Tracking and Runaway
Sent:	Monday, July 16, 2012 19:39:51
From:	Max Byerly (
I recently got this ETX 105 and I finally have a nice clear night to use
it. But I've hit some problems. First of all, let me start out by saying
that I followed the ETX Tune Up on Mike's website that you wrote Dr.
Clay. It is very well written. So I did all of those things and in
having these issues tonight:

1) Tracking error. During tracking, it will jerk for a track and send
vibration so the object wiggles when it tracks. It will also drift until
it gets to that point and then jerks back. 

2) Declination runaway. While observing tonight, I was observing M3 and
the scope took off in declination and would not stop. You cannot push
the hand control to stop, the only thing you can do is turn the scope

3) Object runaway. I put the telescope on M51 and watched it slowly
creep out of the FOV. It took about 2 minutes, but the motors were
moving a bit faster than tracking.

4) Declination clutch over tighten. You've really got yank that clutch
to tighten it. And I cleaned all the grease and stuff out of it, except
for on the gears.

Help on these issues would be very appreciated. Why can't I get a scope
that works great. Haha.

Meanwhile the goto on the 105 is quite accurate, every object placed in
my 32mm eyepiece.

Clear Skies,


Sent from my iPhone
Mike here: Systems 1, 2, and 3 can all be cured usually by doing a CALIBRATE MOTOR and TRAIN DRIVES. As to 4, do not over tighten the axis lock. Otherwise you risk breaking the lock mechanism.


I did all of those things before I came out tonight. I followed that
guide for tuning up the ETX exactly.

Mike here: What version of the AutoStar software is in your AutoStar?


43Eg, the most current for version 4

Mike here: Yep, 4.3Eg is the best current version for the older AutoStar #497. It could be that the AutoStar software is corrupted. You can reload version 4.3Eg but you'll need a #505 serial cable (easily made) and a RS-232 serial port on your computer. Other than that, a possible simple fix is to redistribute the lubrication if the encoders are dirty. Unlock the axes and slowly rotate the tube by hand horizontally, hard stop to hard stop, and up and down, several times back and forth. Two other things to try: Reverse the HBX end-for-end. And check the HBX port pins for dirty, bent, or too depressed pins.


Is the tracking kick maybe caused by something too tight in the RA base?
Maybe gears or bolts or something too tight, because when you also slew
on fine adjustment (3-5 speed) it will move but this jerky motion. So
maybe something is way too tight or adjusted wrong. Any idea?


Sent from my white iPad 2
Mike here: You can check for loose gear mounts or lose gears on their shafts. Broken gear mounts or broken teeth can also cause that.

Subject:	Need help with my ETX90
Sent:	Monday, July 16, 2012 15:04:59
From:	Hugh Simpson-Wells (
Not sure if you are offering help. Please advise where I can get help if
I bought a Meade ETX90 telepscope from someone who had obviously never
got the computer working properly (I asked him, he said he didn't). The
problem I have is that when you do an easy align, it goes up past the
vertical and keeps going. Obviously it hits the stops, and I have to
turn it off.
I have spent A LOT of time on this and it is quite repeatable. I have
reset it, calibrated and trained the drives. Always the same.
I think I know what is going on but it sounds really unlikely. Specific
symptom: I set up the home position (North, Horizontal); I start the
easy align, it selects Arcturus - great I can see that, in the West
about 45 degrees up; trouble is that it moves 45 degrees right, and then
tries to go up past 90 degrees (which it shouldn't). What it should be
doing is going left about 95 degrees and up 45. It is as though the
motors are reversed (when it thinks it is going left it is going up, and
when it thinks it is going up it is going right.
Is there any way it could be doing this? If not, what else?
Mike here: I can try to help. Since you have done the RESET, CALIBRATE MOTOR, and TRAIN DRIVES steps, we can rule those out for solving the problem. It could be that the AutoStar software is corrupted. You can reload version 4.3Eg but you'll need a #505 serial cable (easily made) and a RS-232 serial port on your computer. Other than that, a possible simple fix is to redistribute the lubrication if the encoders are dirty. Unlock the axes and slowly rotate the tube by hand horizontally, hard stop to hard stop, and up and down, several times back and forth. Two other things to try: Reverse the HBX end-for-end. And check the HBX port pins for dirty, bent, or too depressed pins.


Thanks. Reversing the cable didn't work, but it got me thinking.

The arrow keys are the wrong way around too - both on the electronic
controller and the computer controller. As I look at either of them with
the writing upright, the up and down arrows do left and right motion -
and vice versa. This is on both controllers, with both cables. Can you
confirm that this is wrong?

Assuming so, this points at the port, or further into the telescope.
Examining the port, the metal connectors look evenly spaced, clean, and
consistent in their action. When you push in a connector it moves
nicely, and clicks home. I do not think there is a mechanical problem
with the port. Can I get access to the inside and see if there is any
obvious problem with the wiring?

Mike here: UP/DOWN moves LEFT/RIGHT with both the standard EC handcontroller and AutoStar? Definitely reversed wiring someplace.



Is there anything here I could reasonably have a go at myself (I am
reasonably technical) or is this a job for Meade? The telescope is quite
old - well beyond any warranty expectations.

Mike here: You can try Meade but they may not repair since it is an old model. Alternatively, you can use Dr. Clay Sherrod's Supercharge Tuneup Service. If you want to dig into it yourself, there are many disassembly articles on the Helpful Information: Telescope Tech Tips page. Be certain to read the article "Disassembly Procedure" first.

Subject:	ETX 105
Sent:	Friday, July 13, 2012 15:25:38
From:	Max Byerly (
I'm going to pick up a ETX 105 from a gentlemen who lives relatively
close. He wanted $200 bucks for the scope, dew shield, electric focuser
and autostar. I already have a tripod. This will be my third ETX. I have
a ETX 60 and 70 and at one point I had an ETX 90. I want some advice
from you as to what I should do over the weekend. It's not going to be
clear for 3 more nights here and I want to get this 105 in fine working
order ad get it optimized perfect before the first night. 



Sent from my white iPad 2
Mike here: Sorry for the delayed response. As mentioned on the Announcements: Site page on my ETX Site, I currently have limited email.
Other than installing fresh batteries, doing an AutoStar Reset/Calibrate Motor/Train Drives, setting up the AutoStar for your location and preferences, and maybe cleaning the optics (but only if necessary), not much else to do until the sky clears and you can check the collimation by doing a "star test".


Well I got it and it seems to work wonderful. But I noticed that it
needs excessive tightening of the Declination clutch to lock the tube in
place. I don't like using that much tightening. I was looking around
your site for a fix but I found one for the 90 and 125 but not the 105.
The one place suggested gluing the two metal pieces together perfectly
on top of each other but I don't want to do something that would
possibly ruin it. Do you know a fix since you own a 105. Like it said
there is stuff for the 90 and 125 but not the 105. The 125 has a extra
washer, but the 105 doesn't.

Any help would be great,
Mike here: The only fixes I have are on the ETX Site. My ETX-105PE is still working great.

Subject:	Tripod
Sent:	Monday, July 9, 2012 07:29:05
From:	Kathy Clark (
Good Morning - we were given your name in hopes of finding a tripod for
the following model # ETX125EC Meade astro telescope.

We had a catalog that should these options - Meade 883 Deluxe field
tripod or 884 or 887 Advanced Field Tripod.
Do you have for sale or know where we can purchase one?
Thanks. Kathy Clark
Mike here: As noted on my ETX Site home page, I am not a dealer. Any Meade telescope dealer should be able to provide you with a tripod. For a list of dealers, see the Astronomy Links page.

Subject:	ETX-125 focus shaft
Sent:	Friday, July 6, 2012 13:35:50
From:	Keith Collins, DMD (
Hi, I have an ETX-125.  I was attempting to adjust the set screw on the
focus knob today, and as I removed the focus knob the entire shaft
disappeared within the case.  Could you please point me to a resource
about retrieving the shaft and reassembling the knob?  I called Meade
direct today and they were not very helpful.
Keith W. Collins, DMD
Vancouver, WA
Mike here: Sorry for the delay in responding. As mentioned on the Announcements: Site page on my ETX Site, I currently have limited email access.
See the article "Focus Shaft Fix" on the Helpful Information: Telescope Tech Tips page.

Subject:	Re: Declinaison Gear failure
Sent:	Wednesday, July 4, 2012 21:06:17
From:	GRANIER colin (
This mail just to thank you for your earlier help
The little ETX-90 is a second hand and is not perfect, but with your
feedback from a few weeks ago, it is now perfectly operatable
Thought you might appreciate having a mail saying "all is well"
Best regards

Subject:	ETX-90 on an iOptron Cube?
Sent:	Tuesday, July 3, 2012 13:13:50
From:	Ray Wartinger (
It's been quite awhile since I visited or posted on your site and I'm
very happy to see that you're still "in business". I am wondering if
anyone has had any experience using an iOptron Cube as an alternative
mount for their ETX OTA.  My specific scope is an original ETX-90 with
what I consider to be a very poor fork mount and drive system. I have
spent many hours trying to improve it (as I'm sure many others have too)
but it remains the main reason I rarely use this telescope. I even added
a JMI Micro-Max DSS to it but that was basically like putting lipstick
on a pig. It works but the RA drive movement is so poor that it's more
trouble than it's worth. I see that Amazon currently is selling an
iOptron 80mm scope on a Cube with a tripod for $359 so even if the scope
is lousy, the mount may work well with my ETX. I'd appreciate hearing
about any personal experiences anyone may have with this setup.


Slight correction: The iOptron scope I mentioned costs $410 on Amazon,
but it's $360 on
Here's a link
I'm mainly interested in the Cube mount but the scope might be OK.
Sorry for the confusion,
Mike here: I don't recall any iOptron reports. I'll post your messages on the next ETX Site update.


Thanks Mike.

Subject:	Etx 90ec
Sent:	Tuesday, July 3, 2012 11:34:32
From: (
Hello i am really new to ETX telescopes,but no so new telescopes in
general.I have a few telescopes but all are refractors.This ETX is a
first for me and im not quite used to the sounds  of this scope .Are
they generally this noisey when using the controls for Vertical and
Horizontal movement,Everything seems to work very well except for the
sounds at different speeds?
Mike here: Sorry for the delay in responding. As noted on the Announcements: Site page, I currently have limited email access.
Yes, the ETX can be noisy, especially at higher slew speeds. You can use a lower speed for GOTOs to reduce the volume.

Subject:	ETX 70 RA drive non functional- spring repair
Sent:	Monday, July 2, 2012 17:11:33
From:	Peter Ashby (
This morning I won an ETX 70 on freecycle ( an email list / group
dedicated to recycling things and saving old stuff from landfill)
suffice to say this was advertised with a fault, in my response I
indicated I would attempt a repair, and so won the telescope.

Having a fair deal of experience fixing up ETX 80's I quickly
dissasembled the RA clutch mechanism and took the base off, running it
up under power it was apparent there was nothing wrong with the drive
train, the worm was turning just fine, this was a bit of a puzzle until
closer inspection of the base revealed a small piece of plastic, it was
soon apparent that this was part of the spring mechanism that held the
worm in contact with the drive gear. how to fix  this, gluing it back on
wouldnt work, so I started digging through my parts boxes to find just
the  right size spring. I found one but worked out I would have to drill
and tap the casting sticking up to support the spring. I wasnt sure I
wanted to tackle that just yet. Another came to hand, this one was
perhaps 1/4" diameter and maybe 5/8" lomg or even 3/4".

This was a little long but held its position well, but had the drawback
it pushed the worm gear too far forward to easily engage the RA gear. as
a safequard I cut a 1/4" wide strip of duct tape, this was wrapped round
the last coil of the spring and also round the cast post that the spring
acts against, at the motor end it fitted round the remains of the
plastic spring.

To reassemble the gearbox was pulled back to compress the spring and a
fine long shafted screwdriver was used to hold the gearbox in this
position while the base was put back on, when the gap was down to 1/16"
the screwdriver was removed as the base popped home. this allowed the
spring to push the worm into contact with the RA drive gear.

the autostar was plugged in and turned on, and the drive  checked for
function - everything worked so the clutch mechanism was reinstalled and

End result one fully functional repaired ETX70 - rescued from landfill.

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