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Last updated: 28 February 2010
This page is for comments and user feedback about the "ETX Classic" telescopes. ETX Classic models 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, ETX-LS, 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: Meade ETX 125 base
Sent:	Sunday, February 28, 2010 14:28:15
From: (
I looked but could not find it on your website.  Does the bolt of the
ETX 125 base just unscrew and then the clutch assembly comes out?  A
brief explanation would be appreciated.  Any info would help.
Mike here: The information that I have is posted on the Helpful Information: Telescope Tech Tips page in the various disassembly articles.
Subject:	Re: ETX-105 Right Angle 8 x 25 rubber eyecup
Sent:	Wednesday, February 24, 2010 13:55:04
From:	Eric Ball (
Thanks for taking the time to reply.

Can't see anything at Telescope  Warehouse but it seems ScopeStuff may
have what I'm looking for.

Thanks again and all the best,

Mike here: Send an email to Telescope Warehouse; they may still have what you want.
Subject:	ETX-105 Right Angle 8 x 25 rubber eyecup
Sent:	Tuesday, February 23, 2010 23:41:27
From:	Eric Ball (
When showing my ETX-105 to my 3 year old grandson (figure start-em
young) he, rather naturally, held the rubber eyecup on my right angle 8
x 25 finder and, unfortunately, it tore.

Can't seem to find one locally (Christchurch, New Zealand) but visiting
the US in April and wonder if anyone can recommend somewhere in New York
city where I can obtain a spare - or two!

All the best,

Mike here: Two thoughts: Try Telescope Warehouse (link on the Astronomy Links page). Alternatively, try ScopeStuff; they have eyecups (
Subject:	Meade ETX 125 base
Sent:	Tuesday, February 23, 2010 14:44:21
From: (
Is there anywhere I can look to find a schmatic breakdown of a Meade ETX
125 base unit?? How to take it appart step by step?? Mine has some rust
and the gears are almost locked up I need to take it appart clean it
lube it and put it back together.  Do you know where I can find some
break down pictures???

Any help would be appreciated.
Mike here: Gee, I seem to have answered this question several times recently! There are no schematics available of the ETX itself. However, there are several disassembly and "inside" articles, some with photos, on the Helpful Information: Telescope Tech Tips page.


Thanks sorry I did not know.   I will look for it.


Can the base of the ETX 125 be completely taken apart or is it riveted
Does the center bolt come all of the way out? 
Mike here: Yes, you can pretty much disassemble (and ruin, if you are not careful) the base and bolt.
Subject:	Video instructions for ETX 125 PE  with LNT
Sent:	Tuesday, February 23, 2010 10:25:22
From:	andy christmas (
I  acquired the above several months ago (my post retirement toy) and
after looking at your site agree wholeheartedly that the manuals are
either inadequate or very confusing  There seem to be 2 different
methods for setting the home position - I have tried looking at the
Meade sites instructional videos, but they too seem inadequate, in fact
I can't play all of the  "Automatic Alignment"  segment at all  as the
file seems corrupted (my garden only allows a limited view of the sky
and I often can't see the "Autostar selected star"  can I choose another
one ?)

I have used it manually so far (& using the Alt/Az drives) and the
optics are pretty good, but finding some of the deep space objects is
beyond me as a "new boy" and I can't set up the track function etc once
I find something interesting

Are there any other "home made" instructional videos around that you
know of (that are any good)

Andy (south coast UK)
Mike here: There are indeed TWO Home Positions, one for Auto Align with the PE models and the other for non-Auto Align with the PE and non-PE models. They different only in the horizontal starting position. For Auto Align with the PE models, you rotate the telescope tube counterclockwise to the hard stop and leave it there (the telescope will be pointed towards the southwest). For non-Auto Alignment, the rotation is still CCW to the hard stop but then you rotate it back about 120 degrees to point the telescope towards True North. In both cases, the telescope tube should be level and the control on the base on the west side of the tripod. If you can't see the selected alignment star(s), you can tell the AutoStar to try another star by pressing the DOWN arrow key (at the bottom of the AutoStar handcontroller). Alternatively, if you start out with an accurate good Home Position, you can just accept the stars as centered even if they are obscured by an obstruction.
Subject:	ETX-125 Smoked Declination Motor or Board
Sent:	Tuesday, February 23, 2010 08:54:55
From: (
Literally, I did see smoke rising from the declination side of the
scope.... The scope still power up and the Autostar II is functioning.
The horizontal motor works fine but declination is dead....

The scope is out of warranty and I am wondering what options do I have
other than:
1. Sending it to Meade for repair @ $165 + $15 shipping
2. Dropping it off at OPT (I live in San Diego) @ $65/hr
Can I purchase the parts directly and do the repair myself or ???
If this topic have been covered, my appologies....
Mike here: Meade does not sell ETX replacement parts directly. Try Telescope Warehouse (link on the Astronomy Links page). Also, if you are using the AutoStar II, stop. It won't work. Use an AutoStar #497.
Subject:	etx 125 focus knob
Sent:	Monday, February 22, 2010 16:54:46
From:	jon (
Please tell, on the etx125 when you are turning the knob anticlockwise
should the spindle travel out of the back then when you turn it
clockwise move back to the housing
Mike here: The focus shaft does move in and out on the ETX non-refractor models as you rotate the focus knob.


Thanks mike

Subject:	re: EXT-80AT-TC Lithium Battery
Sent:	Monday, February 22, 2010 10:03:30
From:	richard seymour (
All that the Lithium battery powers is the -clock- which is referred to
by the 494 during power-up.
During the use of the scope the battery-powered clock is -not- accessed,
timing duties are taken over by the Autostar.

Those of us with older ETX-70/80/90's don't have such a clock, hence
Mike's puzzlement.

have fun


From:	Ron Harries (
So, as I understand it, the lithium battery preforms the same duty as
they do in a VCR Computer etc. I keeps track of the information you put
in when you initialize the scope.  As I have lost the part that holds
the battery in place, I have semi permanently installed the battery with
a carefully crafted piece of duct tape. I think the lithium battery will
last as long as the scope, if not longer.

Thanks to both of you for your help

Ron Harries


All of the "operate a telescope" information (settings, etc) are kept in
the autostar itself, and do not require a battery to be retained.  There
is no  battery in the autostar.

The battery in the TC unit keep the clock -running-, not static storage.
There is no static storage in the Meade clock chip. This differs from
such examples as the BIOS parameter area of a PC's clock chip.

In Meade scopes without the TC unit (or a GPS receiver), the owner is
simply asked to provide the time and date at every power-up.

You are correct that the lithium cell should last many, many years.

have fun

Subject:	etx-90 right tube adapter
Sent:	Monday, February 22, 2010 08:50:38
From:	anthony paschal (
Just got a used etx-90, and right tube adapter show all of the problems
that you have detailed in your how to step by step. (which is really
great) I contacted meade this morning and was told i needed to send the
entire telescope in. Of course I politely objected as to why I would
mail 15 lbs of telescope for a 1 pound piece of plastic. Ended up
leaving a voicemail with a supervisor, much like your original post. Are
there any other avenues of part replacement that I've been unable to
locate. Also the scope logic site says they are out of business.  Thanks
for your efforts.    Tony Paschal
Mike here: Sorry to hear about Scope Logic. They were the only company I recall that sold a replacement Right Tube Adapter. However, you may be able to do the repair yourself; see the article "ETX-90EC DEC fix" on the Helpful Information: Telescope Tech Tips page.
Subject:	Ready to start again
Sent:	Saturday, February 20, 2010 14:22:13
From:	James Wilkins (
I have an ETX Classic that has not been used in 6 years.  Finally, in my
retirement, I am ready to start viewing again.  What do I need to do get
get my scope working again?

Jim Wilkins
Mike here: Time and clear skies are what you need! Of course, fresh batteries too. Then enjoy it as you did years ago. Once you find out how the ETX and YOU are working, then you can decide what might be required.


IS there any "maintenance" I have to do first?  For instance, do I have to worry about dried grease or will it slew smoothly?

Mike here: It won't hurt to unlock the axes and slowly move the tube around both axes, back and forth, several times. Of course, if the batteries had not been removed, check the battery compartment for corrosion.
Subject:	ETX smartfinder alignment problem
Sent:	Friday, February 19, 2010 20:07:25
From: (
I have a brand new ETX 90 PE and I am having problems getting the red
dot to line up with the optics.  I have the vertical set screw turned
all the way in to stop but the red dot is still off by 1 to 1 1/2
degrees below the target star.  If I push up on the front of the
smartfinder I am able to center the red dot (not a good fix).  Any
Brett Ohnstad
Wyoming Mn
Mike here: There are several SmartFinder tips on the Helpful Information: Telescope Tech Tips page. See if any of those help.
Subject:	ETX90PE Electric schematic
Sent:	Friday, February 19, 2010 08:02:27
From:	Sabine Cyrille (
I have an ETX90PE telescope with LNT module. Since one week, the LNT
module doesn't work anymore. After taking to pieces the LNT and
telescope base part, it seems there is some lost connection.

So, I'm looking for the telescope electric schematic and may wire the
LNT in a different way (not by going through the telescope axe).

Does somebody have this thing ?

From France.
Mike here: There is no schematic available. Have you checked the LNT battery? There are several LNT troubleshooting articles on the Helpful Information: Telescope Tech Tips page.


Thanks for your quick answer.

I have first change the batterie but nothing appends. After testing the
4 wire from LNT to mount base, there is one wire without electric
continuity. And for other, the wire color has change.

That's why I'm looking for the electric schematic.

So finally, I'll use your great web site to disassembly the telescope
and try to recover the connection and LNT functions.

If you find soon (by chance for me) schematic, I still interesting in.

Thanks again and thanks for sharing info through your web site.

Subject:	EXT-80AT-TC Lithium Battery
Sent:	Thursday, February 18, 2010 20:45:20
From:	Ron Harries (
The lithium battery in my EXT-80 has come loose. Actually the
compartment for it is broken. I believe I can fix that part but don't
know where to go from there. There is plenty of information on you site
regarding the Autostar 497 but not so about the 494. Could you please
direct me in finding information.


Ron Harries
Mike here: I have no information on a Lithium battery case for the ETX-80. As to the AutoStar #494, what information do you need?


I thought, by loosing the lithium battery, I might loose what the
factory had installed in the ROM. Not so. I put the battery in using a
plastic pill bottle cap and the main battery package to hold it in
place. Initialized the AS #494 and all is working well. That will be 
untill I have to change the main batteries. What I need is the part that
at holds the lithium battery in place.

Ron Harries

Subject:	etx 125 focus knob not moving mirror
Sent:	Thursday, February 18, 2010 15:53:58
From:	jon (
Where on your great site can i find advice on how to fix. When i turn
the focus knob anti clockwise the stem travelles out of the tube, thus i
quess not attached to what it should be.
Mike here: See the article "Focus Shaft Fix" on the Helpful Information: Telescope Tech Tips page.
Subject:	RE: ETX-125 Azimuth drive questions
Sent:	Thursday, February 18, 2010 13:45:32
From:	George Reiswig (
Well, last night was the first night in a LONG time when it wasn't
raining, so I got to go out and test my newly-trained drives.  Thank you
both, again, for your help in getting it set up.

I encountered two oddities/problems using the scope in Alt/Az mode.

1.  I may just be using Autostar incorrectly - when I was pointed at an
object, browsed the menu to the next object, and then it the GOTO
button, the scope would say "Slewing" but didn't move.  Is it the case
that you have to hit ENTER first, then GOTO?  I got to wondering if I
was just telling it to repeatedly go back to the same object it was
already pointed at.

2.  Twice, I had to shut the scope down because it was trying to slew
past the stops on the azimuth.  This was quite a surprise, since I had
followed the process you (Mike) outlined here in setting up the Home

		1. Position the whole ETX and tripod system with the ETX control
		panel on the west side. This doesn't have to be exactly due West
		but should be as close as possible.

		2. Level the ETX base. Again, this doesn't have to be exactly
		level (I usually just eyeball this).

		3. Unlock the altitude axis and position the ETX Optical Tube
		Assembly (OTA) to 0 degrees. The ETX OTA should be parallel to
		the ETX base. Relock the axis. If the scale is off it can be
		adjusted by loosening the knob, rotating the scale, and
		retightening the knob.

		4. Loosen the azimuth lever and rotate the ETX OTA
		counterclockwise until you hit the stop. Counterclockwise means
		moving it from (for example) South to East to North to West.

		5. Now rotate the ETX OTA clockwise back to the North. This is a
		rotation of approximately 120 degrees or from pointing towards
		the Southwest through West to North.

		6. Continue with the Autostar Alt/Az initialization and

The only things that I may not have done as above were to

       ensure that the OTA and the base were parallelinstead, I tried to
       level the tripod, then level the OTA with bubble levels.  That
       *should* theoretically be the same thing, but likely wasn't
       precise.  Is it more important to simply get the OTA parallel to
       the base and pointed to true north?

       Point the control surface of the scope due westit may have been
       more WSW in orientation, and it was near that direction that the
       scope would start to bind against the stop.

Butby way of keeping you informed about my initial inquiry, the scope
did a great job of finding Mars, the Orion Nebula, and the Pleiades.  I
had VERY carefully trained the drives, under- or over-training them each
in turn until I was able to slew dead center to a terrestrial object. 
That seems to have done the trick.  Now to iron out some of these other

George Reiswig


From:	P. Clay Sherrod (
You might try to assure that you are in Alt Az mount mode and not
polar.  Attempt to get the setup as close to home position (as you
described) as possible and make absolutely sure that all your defaults
(time, date, location, time zone, etc.) are set correctly.  Remember
that Autostar does not remember time and date, but will remember your
location IF you put it in correctly.

You must press ENTER, then GO TO to find objects.

Check your defaults and make sure that you have the hard stops
positioned exactly as described.

Best of luck.
Dr. Clay
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West 
Mike here: Besides what Dr. Clay said, you can check for rotational obstruction. Unlock the horizontal access and slowly rotate the telescope around from hard stop to hard stop. It should go almost twice around. If you get significantly less than that, don't force it to move. There could be a wire preventing further movement and you don't want to cut it.

And more:

More decent weather last night, although not very good seeing...but then
I'm new to this anyway, so I've not SEEN good seeing yet.

Anyway, I set up the tripod and scope more carefully north-oriented last
night, and experienced no binding against the stops.  Good!  GOTO's are
quite good, although not perfect...but things appear generally near the
edge of my 13mm Nagler's view.  I assume that's within tolerance, and
certainly pretty darn good from my perspective.

Now I need to start taking Vitamin A, because the only fuzzies I could
make out were the Orion Nebula and the middle of the Andromeda Galaxy. 
Thank you again for taking the time to talk to noobs like me.  Thank
you, thank you!

George Reiswig


That is excellent, enjoy the wonderful sky.

Dr. Clay

Subject:	Meade ETX-90/EC Right Tube Adapter
Sent:	Thursday, February 18, 2010 08:52:54
From:	Tim Magrino (
Does anyone know where I can purchase a right tube adapter for the Meade
ETX-90/EC telescope?  The shaft on the adapter broke and I need to find
a replacement part.  I contacted Meade and they said that the part is no
longer manufactured.  Does anyone know where I can buy the part after
Tim Magrino
Mike here: Contact Scope Logic at They used to sell them.
Subject:	Setting Circles Time error - I believe
Sent:	Wednesday, February 17, 2010 19:13:28
From:	Don Nelson (
Hi, have ocassionally read your ETX pages for years, but having just
retired (Computer admin.) I bought a used EC-90ETX and so am back. I see
your 'Using Setting Circles' page was updated
recently so I am sure the error (I see) just happened. 3 paragraphs
before Fig 3 is the Paragraph:

'Because of the difference in sidereal time and local solar time,
(resulting in all stars appearing to rise about 3 hours 57 minutes
earlier each successive night) you will note that the reference stars
will change monthly as a result. This constitutes the Earth's "Year."
Thus, your ideal reference stars are those identified as bright and
visible, close to your desired object for that particular night you are

I believe the words 'hours & minutes' should be 'minutes & seconds' +
the ing added to appear.

Thanks for ALL your GOOD work!

Don Nelson
'We are the people we are waiting for - Hopi
Mike here: Thanks much for catching the errors. I'll update the page. I've cc'ed Dr. Clay Sherrod, who wrote the article.


From:	P. Clay Sherrod (
Yep....good catch and thanks...!

Dr. Clay
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West

Subject:	etx-125 schematics
Sent:	Sunday, February 14, 2010 16:05:38
From:	Bill Nelson (
I am looking for schematics for the electronic components for the Meade
ETX-125. My son inadvertently plugged in a 12 volt AC power supply.
POP.....If you could help it would be appreciated.

Bill Nelson
Mike here: There are no schematics available of the ETX circuit board. However, if the AutoStar is what was damaged, there are a couple of articles on that on the Helpful Information: AutoStar Info page.


Thank You!

Subject:	Less than 360 degree rotation.
Sent:	Sunday, February 14, 2010 12:40:50
From:	Ian Rayner (
I have recently purchased my first telescope, an ETX 125PE.  After
reading the manual and some indoor practise I have found that the scope
will not rotate over 360 degrees from stop to stop.  The manual states
that it should rotate 630 degrees.  However, a manual I found online for
an older model confirmed the limit was 360 degrees.  Have I got
something wrong, or is this a misprint in the manual?  The scope did try
to pass one of the stop positions whilst slewing to an alignment star,
so my guess is the 630 degrees is correct?  Do you have any tips or
advice regarding a fix I could undertake, as I do not believe the online
UK retailer I purchase this from has heard of "Customer Service".
Many Thanks,
Ian Rayner
Mike here: The ETX-90/105/125 models should rotate nearly twice around hardstop-to-hardstop. There are typically two causes if it does not rotate this distance: an obstruction or a broken hard stop. If you open up the base you mean be able to see which it is. If it is an obstruction, such as a piece of debris or a wire, you may be able to correct that. Use caution if it is a wire as you don't want to cut it or break the connections. If it is a broken hardstop, while you may be able to repair it, I would recommend contacting the dealer for an exchange. If you can't find the cause or cure it, then you should definitely contact the dealer for an exchange.


Thanks Mike, I will follow your advice.



Subject:	Focus Problem - EXT 80
Sent:	Sunday, February 14, 2010 12:29:02
From:	Ron Harries (
I have an EXT 80 (my first store bought scope). I purchased a Barlow,
Meade, #126 (2X).

My problem is that with the above Barlow and either of the two included
scope eye pieces, the scope will not focus to infinity. Close but not
all the way. If I could bring the Objective Lens about 2 mm closer that
would be all that is needed. There is plenty of room ( 2.5 cm) before
there would be a problem with the forks.

Is there some way of adjusting the focus so it will bring the Objective
tube in this small amount?

I enjoy your sight very much and thank you in advance for any help you
can give.

Ron Harries, Salmon Arm BC
Mike here: There is no easy way of changing the focusing mechanism to allow for such a focus adjustment. However, lets confirm something. I thought the ETX-80 had a built-in Barlow Lens. Does your model NOT have that? If it has one, do the eyepieces reach focus with it?


Yes, it does have a built in barlow (I think a single element lens) and
tey eye pieces do focus. I bought the barlow hopping to improve quality.

Mike here: The refractor ETX models do not have a lot of focus movement so I suspect adding the second Barlow Lens puts you just beyond the focal plane.


However, I think I have found an answer to the problem. The portion of
barlow (or should that be Barlow) could be cut down by up to five mms. I
would have to find some way to thread the Barlow.
Mike here: Keep in mind the theoretical maximum magnification when increasing the magnification 4 times. If you don't know what that is and how to calculate it, see the ETX FAQ page.
Subject:	Old ETX 70AT user
Sent:	Sunday, February 14, 2010 00:37:10
From:	gwl (
It's been a couple of years since I visited your site.  Glad to see you're
still running it and keeping it up to date.  I kind of got out of
observing in the last few years, but am "dusting off" my ETX70 as the bug
is getting me again. I know the 70 isn't the biggest or the best scope
out there, but I always had a lot of fun with it and observed something
new almost every session. I think I only paid $129. refurbed from Meade
4or 5 years ago and used it well over 100 times in the first couple of
years with no issues.

I don't have any questions...I just wanted to say thanks for keeping up
the site.
Ridgeway Ohio

Subject:	Need Help In Assembling Lower Clutch
Sent:	Wednesday, February 10, 2010 21:06:23
From: (
If you remember me from the other day I am was disassembling my ETX-70
to repair the focus. That went great! I have assembled it and the scope
slews up and down.

However, the side to side slew is intermittent. I have disassembled
(again) and attached a photo. Are the parts in the right order? Is the
big washer with the prongs turned the correct way?

Thanks sooo much!
Kevin Kennedy
St. Peters, Mo.


Mike here: Ah yes, as I've mentioned before on the ETX Site, the importance of documenting what you do when performing major surgery! Anyway, see the article "ETX-70AT Repair Guide" on the Helpful Information: Telescope Tech Tips page. Perhaps that will help. If not, there are many other disassembly articles there that may have the info you need. Or not.


Thanks again for your prompt response......and yes, documenting would
have been time....

Subject:	ETX-80, AutoStar 494 and computer control
Sent:	Wednesday, February 10, 2010 06:15:26
From:	Sven-Ove Auno (
I hope you can give me an advice regarding computer control of my
ETX-80AT-TC. I normally use AutoStar 494 for control, but would like to
control the telescope from my laptop (PC and Windows Vista). I have
Carina Software Voyager 4.5 in the laptop, but this software does not
include ETX-80 as an option for controlling the telescope. Do you know
if it will work with some other telescope option (e.g. ETX-90 or LX200

Best regards,
Sven-Ove Auno
Mike here: First, you need a #506 serial cable. That cable is not easily made so you will have to purchase one. Alternatively, you can get a #497 AutoStar and easily make a #505 serial cable (see cable section on the Helpful Information: AutoStar Info page). Second, if your computer does not have a RS-232 serial port, you will need a USB-serial adapter. However, not all USB adapters work reliably with the AutoStar; see the article "AutoStar and USB" on the AutoStar Info page. Once you have the right hardware, you can select the ETX-90 model in Voyager 4.


Thank you for your quick response. Have I understood correctly that if I
have the correct cables and adapters it will work with my #494 AutoStar
if I select ETX-90?

Best regards,

Sven-Ove Auno
Mike here: Yes.


Thank you.

Sven-Ove Auno

Subject:	etx-80 objective cell compatibility with etx-70/60?
Sent:	Sunday, February 7, 2010 17:33:55
From:	Mark Hatch (
I know that you can take an etx-70 objective cell and put it on an
etx-60 OTA. (They share the same bottom part of the OTA. What about the
etx-80? Does it share the same base with the 60/70?

Mike here: Don't know for certain but I suspect that the OTA is different since the ETX-80 has a longer focal length.


Thanks for the reply. I got curious because I saw this stock photo at:

and it looks like the lens cell was just a 100 mm longer than the 70's.


Mike here: There is a difference at the rear of the ETX-80 vs the -70 as well. But I don't know if the objective lens mounting and focus shaft placement is exactly the same or not, or if the focus shaft is even long enough.
Subject:	Re: ETX 125 Dec Fault
Sent:	Saturday, February 6, 2010 02:26:46
From:	John Farrant (
Follow up to my dec board woes.
I decided to use the encoder assembly from the faulty 125 RA board and
connect it to the pic side of the working 90 RA board. This proved
easier said than done! However, I managed to cut the four tracks on the
125 board where the encoder leads to its pic using a small twist drill.
Cutting the tracks with a knife would have caused a terrible mess. I
repeated the same procedure on the 90 board. There are two surface
mounted 56 k resistors near the 125 encoder and these I removed as they
are duplicated on the 90 board. Next, with a 15 cm length of four strand
ribbon cable, I connected the 125s encoder to the 90s pic. I reinstalled
the 125 RA board back in place together with the 90 board - hanging at
this stage - nearby. With the motor connected, I switched on. Eureka!
After a motor test both drives spun into life. My dec fault dissapeared.
All that remains is to fixed the 90s RA board securely in place, reroute
the encoder leads and extend the motor's cable.

I'd like to thank Dick for the circuit information, George Cushing for
kindly sending me a replacement DEC board, and your goodself for your
Best regards,

Subject:	ETX-70 Focus, Lens Cap
Sent:	Friday, February 5, 2010 14:39:59
From: (
I just got a second hand ETX-70.....I have'nt used it yet but in looking
it over it seemed the focus knob was very has loosened some
but I am wondering how much should it turn?.....all the way
around? only seems to go about a half turn. Is that
right?......Also from your experience does anyone offer a replacement
lens cap for this? It did'nt come with one.......Thanks soo much for
your is most appreciated......Best regards, Kevin Kennedy
(St. Peters, Mo.)
Mike here: The ETX-70 focus knob will turn MANY times around when changing focus from one eyepiece to a different eyepiece. So, if you are only getting less than one 360 degree rotation, then the focus shaft is probably binding up someplace. Use caution! It is a real pain to repair/replace. As to a replacement lens cap, try Telescope Warehouse (link on the Astronomy Links page). Alternatively, you can easily make a cap from a cardboard tube or even pieces of flat cardboard. I use the cardboard from the backs of paper pads for many such projects.


Once again thank you Mike. I'll have to do more checking about the focus
knob. It is stiff and I sure don't want to break anything forcing it to
turn. Hope I have'nt bought a lemon, sigh. I'll check your webpages
more. Thanks again!

Subject:	total disaster with etx 80
Sent:	Thursday, February 4, 2010 15:18:37
From:	jeff stonehouse (
Hello again Mike thanks for your quick reply a few weeks ago,that
problem I rectified but I think I have a more serious one now.

In trying to get the scope running as well as possible I downloaded 
what I thought was the  latest Autostar Updater version which
unfortunately was the 5.9 version  and connected to the telescope (etx
80 with #494 handset) with disastrous results,the handset is now
completely inoperable but does light up but it won`t initialise.

I have trawled through your site trying to find a solution (I think
another guy did the same thing recently) but it seems that the 494
handset is what the americans call bricked as its firmware cannot be
re-instated by the user.

What do you think would be my options, can Meade in the U K repair this
unit or would it be a new handset if available.I find it totally
frustrating that in this day and age of technology such a stupid thing
can happen with this awful meade software but I suppose others may learn
from it.
Mike here: There is no user-installable update for the #494 AutoStar. It is strange that the ASU app crashed the AutoStar. You have some choices. See the article "AutoStar RESET from Software" on the Helpful Information: AutoStar Info page; you may (or may not) be able to resurrect it. Or contact Meade for a replacement/repair. Or get a new #494, or even better, get a #497 AutoStar.
Subject:	ETX 70 does a nose dive ...
Sent:	Wednesday, February 3, 2010 14:48:01
From:	Eldred, Kris - Fresno (
My precious ETX 70's tripod leg broke, taking my scope with it as they
crashed into the concrete. (I should have taken a photo to share.) The
camera assembly is smashed in on left side. Is it worth repairing, or is
it time for an upgrade?

I've looked online at the 90, 105 and 125. Local dealer has the 105 PE
and the 125 selling at about $850 per; I like the smaller 105, but worry
that I am shorting myself if I do not consider the 125.

Is there a site that shows what I would see in each with the same size
eyepiece so I could compare? I know the eyepieces I used for my 70 gave
clear images, but they were pretty small. I'm probably ready for clear
and a little larger.
Thanks in advance for your thoughts.
Mike here: Not certain what you mean about the "camera assembly" but if the telescope is no longer optically useful, then replacing it is probably a good idea. You can read my comments on the ETX-90, -105, and -125 on the Helpful Information: Buyer/New User Tips page. There are also many user observation reports on the Helpful Information: User Observations page. There are Telescope and Eyepiece simulators on the Buyer/New User Tips page that you may find useful.


Sorry: The photo port was damaged.

I have been checking out your site, just as I did before I bought the
70. I will check out the places you mention.

Thanks for the quick response.

Mike here: Are you using the "photo", or rather, the rear port for anything?


Sometimes for camera. I plan to take scope out tonight if it's not
cloudy to see if anything else is wrong. Flip mirror is loose, but I can
glue that if needed and if scope is still good. I can live without
taking photos!

And an update:

Taped up my little ETX-70 and got it working well enough. Then I thought
about calling Meade to see if there was a replacement part I could
install. And I needed to know how to fix my tripod.

Since the 70 has been discontinued, they offered to replace the scope
and tripod with the ETX-80 model/tripod for $165.

Seemed like a no-brainer. Some day, I might move up to the big guys!

Thanks for the help!


And more:

I looked for 80 info on your site, but figured it can't be much
different from a 70, really. A smidge more magnification. And maybe this
time I will use the computer!
Mike here: There are many ETX-80 user reports on the Helpful Information: User Observations page. Yes, a little more magnification (slightly longer focal length) and a little more light gathering power (slightly larger aperture). As to using a computer, you'll need a #506 serial cable (not easily made) to talk to the AutoStar #494. If you get an AutoStar #497, you can use the #505 serial cable (easily made, using info on the Helpful Information: AutoStar Info page). Also, if your computer does not have a real RS-232 serial port, you'll need a USB-serial adapter. However, not all adapters work reliably with the AutoStar. See the article "AutoStar and USB" on the AutoStar Info page.


Thanks! Much appreciated. 

Subject:	ETX 125 Dec Fault
Sent:	Wednesday, February 3, 2010 14:28:26
From:	John Farrant (
My ETX 125 has developed an annoying fault and I was hoping you could
help me.

In Terrestrial mode, when slewing from, say, alt 0 deg to +5 deg, the
scope will overshoot by approx 45 minutes and finish up at 5 deg 45
minutes. This occurs for any upward/downward slew - an error of approx
half a degree in the positive/negative direction.  In other words the
scope is overshooting by half a degree in either altitude direction.
Azimuth movement is fine.

In Astronomical mode this overshoot still occurs, but then the ota
slowly creeps back to where it should be! The overshoot occurs at full
speed even if the quiet mode is selected. Tracking and Goto are not

The first part of any vertical slew is at normal speed. It is only in
the final half degree of error movement that full speed takes over.

Obviously I have trained drives, motors etc. PSU is ok - 12v external
power source.

I've tried the following - all items hijacked from a perfectly working
ETX 90:- Replaced the Autostar 497 and cable.

Tried 5 software versions from 2.5 through to the latest. Replaced the
dec board. Changed the dec motor. Tried a different front panel board.
All to no avail.

In desperation I swapped the two four pin RA/DEC plugs over. Guess what?
Fault goes away. Slewing, for example, to +10 degrees 0 minutes - with
the RIGHT key! - and the scope moves UP at normal speed and slows down
when near its target - as it should do - finishing up at +10 deg +/-2
minutes. Perfect! Using the up/down keys to move in azimuth again proves
ok. In other words, swaping the DEC and RA plugs on the front power
board removes the fault. Putting them back where they should be and the
fault reappears.

I'm at a complete loss. Any thoughts Mike?
Best regards, John
Mike here: First, you say the PSU is OK. What amperage is it? Swapping the motor connectors makes it sound like it is not dirty encoders. But the "rubberbanding" you are experiencing sounds like a training issue. I would suggest RESET, CALIBRATE MOTOR, and then TRAIN DRIVES. Be certain to train in both axes. If that fails, reload 4.3Eg (assuming you have a #497 AutoStar and not a #497EP).


I have just changed the RA board and believe or not, the DEC fault has
gone! I really can't understand why a fault in the RA board can affect
the DEC board, although no doubt a Meade engineer could explain it.

The only problem left is how I'm going to mount the ETX 90 RA board into
my 125. It is - unlike the dec board - not identical in size. Providing
I can position the optical encoder correctly the rest of can probally go
anywhere. There's plenty of room. Wish me luck.

I'll keep you posted ..
Thanks for your sound advice.
Regards, John

Subject:	Scopetronix?
Sent:	Tuesday, February 2, 2010 12:52:48
From:	Rick Towns (
I just read an editorial of yours from Oct '07 about the trials and
tribulations of Scopetronix. I had ordered a telescope to camera adapter
from then in December '09 and I'm not having a lot of luck getting a
response out of them. I was wondering if you'd heard any more about
their saga? Currently, it looks like they are still in business under
the brand Observer's Outlet. The website has an e-mail address and I've
tried contacting them through it - no luck so far, however.

If you had any further info on them, I'd love to hear it. In the
meantime, I'll let you know how I make out!
Rick Towns
Barrie, Ontario, CANADA
Mike here: That's an older article. You'll find several more recent discussions of Scopetronix on the Editorial Page.

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