Last updated: 31 March 2003
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:	Mirror Drift on an ETX M
Sent:	Friday, March 28, 2003 22:25:27
From: (Michael Jones)
Need some assistance please.  I just put a Meade Electronic Focuser on
my ETX-90M.  Most of the time when using it, my mirror seems to drift a
small amount to either side, depending on if I am focusing in or out.
Having only use the focus knob with the usual "jitters" previously, I
don't know if this is normal or not.  Is there any thing I can do to
lessen it, or just live with it?

Mike Jones, KC6YWT
Los Angeles, CA
Mike here: There is some image shift with the Maksutov-Cassegrain design as the primary mirror moves during focusing. Since you indicate it shifts a small amount, that would be normal.


Thank you!!

Subject:	ETX-90RA
Sent:	Tuesday, March 25, 2003 8:30:06
From: (Erik Andersen)
I have another question, if I'm abusing the privilege by asking too much
let me know. :) I'm looking to buy my brother the ETX-90RA which has the
#884 tri-pod (same as mine) for $299.00. He says he doesn't mind
manually moving the scope since it does track objects. What is your
opinion of this scope?

Will Jupiter (planets etc..) look crisp with these type of telescopes?

Thank you,
Erik Andersen
Mike here: The ETX-90RA is the same model as the original ETX model that I purchased in 1996 (and that started the ETX phenomenon and this ETX Site). You can read my initial comments on the Buyer/New User Tips page, under the "Impressions" area.
Subject:	ETX help advice needed (btw GREAT SITE!)
Sent:	Sunday, March 23, 2003 16:33:04
From: (Timothy Hagner)
Thanks for putting the time and effort to build such a resourceful site!
I visit it quite to see if anything new is posted or just for

anyway I'd like to know the opinion of a much more experienced observer.
Most ETX90'ers will agree that the stock finderscope is 1)too small
aperture 2)straight through and few other things.

Thats why I have been contemplating a Orion 9X50 Right Angle (correct
image) finder as well as an Orion EZfinderII (red dot) which would go on
the same dovetail bracket and I would swap them back and forth as each
fulfills its respective task. My question is as follows:
Is the 9X50 too big/heavy for a ETX90-RA?
How would you attach the Orion dovetail bracket if I dont want to
disturb the beautiful finish of a brand new ETX90-RA?  double stick
tape? is that strong enough?  Epoxy?

Thank you for your help, advice and a great site!
Mike here: Yes, the finderscope has its limitations but it also has its uses. Some new amateurs get disoriented when looking down (when using a right-angle finderscope) when the telescope is pointed up. As to larger finderscopes, check the Accessory Reviews - Finderscopes page for some comments. A large one will look odd and could complicate tracking unless counterbalanced. Mounting it will likely require more than just double-stick tape; the Scopetronix LightSight can with that but the LightSite is much smaller and lighter.


wow! thanks for the quick reply!

>Yes, the finderscope has its limitations but it also has its uses.

sure!  a monocular to put in my pocket wherever I go! :-)

>Some new amateurs get disoriented when looking down (when using a right-angle
>finderscope) when the telescope is pointed up.

not to worry I'll get used to it and I think the Orion one is a "correct
image" Does that mean that it will not be upside down nor reversed?

Would you say that Orion's 6X30 Right Angle finder would be a better
choice for some SCOTCH heavy-duty double stick clear tape?  I'm not
terribly fond of the plastic meade finder bracket contacting the fork
mount just passed 90 degrees.

One other thing:  how do you remove the original finder bracket from its
socket?  I tried the medium allen qrench but it just keeps slipping as I
try to turn it.

Again, thanks for your patience with someone new to Astronomy as well as
to the ETX system.
Mike here: "Correct image" usually means upright and not reversed left-to-right. A smaller model finderscope might be more appropriate. But I doubt that double-stick Scrotch tape would hold for long; you would likely have to retape and realign the finderscope. As to removing the existing finderscope, I don't recall seeing any definitive way to easily remove it.

And more:

What about Epoxy?  Would that be a better choice?

I probably have no clue what I'm talking about but on page 15 of the
ETX-RA manual it says "Medium Wrench (1/16"): This wrench is used to
detach the viewfinder bracket from the telescope's rear cell".  Does that
mean what I think it means:  that I just unscrew the screw in the back
of the rear cell and the bracket slides off?

Thanks again,
Mike here: Epoxy will work but it is a pretty permanent solution. As to that quote, I must have forgotten about that (only been 6+ years since I've read the ETX-90RA manual!). I justed looked at my ETX-90 and it does appear that it could slide out of the bracket if the setscrew is removed. By the way, keep in mind the limited clearance as the rear portion of the ETX OTA swings through the fork arms.


Thanks alot:  you've really been a great help but just please bear with
me for one last question:

Where would you mount the bracket?

Right side, left side, directly in from of the eyepiece rear cell or on
the main tube?

Thanks and keep up the great site,
Mike here: I've done two types: I put the LightSite to the right side of the eyepiece (and kept the Meade finderscope (with a Shutan Right Angle Adapter) on the left. I have also mounted (temporarily) a Rigel QuikFinder forward on the OTA using strong rubberbands.
Subject:	disassembling an ETX 90 from the drives
Sent:	Sunday, March 23, 2003 4:42:13
From: (Werner Schaefer)
I'm using an ETX-90 EC and in future I will use it only as an spotting
scope (like the ETX-90 Spotting Scope). Is there any help in your
archive for disassembling the OTA from the drives / fork mounts ?

Thanks for your answer.

Werner Schaefer

from Switzerland
Mike here: See my early ETX-90EC comments (; at the end I discuss removing the OTA.


Thaks for your Answer. I did it.

Greetings from Switzerland


Subject:	Motor drive
Sent:	Sunday, March 16, 2003 12:56:32
From: (Frank Frick)
Sorry to bother you with this.  But I just set up my Meade ETX-90EC for
the first time today.  I can get the motor drive to elevate and lower
the tube, but nothing seems to happen (other than the sound of the motor
running) when I attempt to turn the scope from right to left.  Am I
doing something wrong, or is something defective?
Frank S. Frick
Mike here: I assume you are using the standard handcontroller and not the Autostar (not that it matters though). Does the azimuth lock lever tighten sufficiently? You can tell by pushing on the tube to see if you can easily move it by hand. "Easily" being the operative word. If the telescope can be moved easily by hand when the lever is locked, you may need to adjust the lever position. See the item "I can not move the Right Ascension (azimuth) lever enough to fully engage the lock" on the FAQ page.


Thanks for the rapid response.  I followed your instructions and my unit
works fine now.  Thanks again!

Subject:	meade etx on a meade ds 114 mount
Sent:	Saturday, March 15, 2003 18:01:51
From: (Mike forster)
Anyone out there attemted a meade etx 90 ra on a meade ds 114 computer
reflectordigital mount?? The 2 mount rings on the meade 114 look like
they "might" hold the etx with some modifications.   Thanks, Mike in
Mike here: See the article "Putting ETX-90 on DS-60" on the Telescope Tech Tips page.
Subject:	Got my ETX90 back from Meade
Sent:	Thursday, March 13, 2003 15:40:57
From: (James Booth)
Here is the update for my inoperative RA drive we talked about on
February 10.

I got my ETX 90RA back from Meade today.  (4 weeks for turn around on
warranty.)  They must have changed some internal parts, because the RA
lock engages in a different spot now.  But the important thing is that
it actually works now.  One thing that I am ticked off about is that I
sent the scope to Meade with brand new alkaline batteries in it, and
they returned it to me without the batteries.  They never said to take
them out before shipping it. I would have taken them out if they had. 
So now I am a few dollars out on that deal.  Well, now all I have to do
is wait for a clear night!

James Booth

Subject:	re: questions,questions.
Sent:	Wednesday, March 12, 2003 21:20:45
From: (Richard Seymour)
As Mike hinted,
Full background info on percents, etc. is under:
 The Ratios, Focal Lengths, etc. is programmed into the Autostar by
 Meade... there are over 22 models covered by the current version
 of firmware (it "asks" the motor controller cards to identify
 themselves... based upon their response, you get different Telescope
 Models listed).
 have fun

Subject:	questions,questions.
Sent:	Wednesday, March 12, 2003 8:26:03
From: (Ross)
I have two completly different questions.I thought I would try and get
them over with with one letter.

On the #497 autostar,the manuel says do not alter the AZ/RA and the
ALT/DEC ratio.They say it's referring to the gears that were
installed.Ok so where is the autostar getting this,from the entry
under,what kind of scope it is and focal length?? Then further along in
the menu it goes to AZ/RA and ALT/DEC percent.Doesn't even mention these
in the manuel.So now I'm lost!!!

K ,second question.I have an old 4500 meade reflector,with that massive
equetorial mount.

I've searched and searched on your site,probaly just missing it.I want
to construct or purchase a mount for the top of the tripod that will be
compatible with my 90EC. It really seems like a sturdy tripod.Just do
not have a clue where to start.

Thank you for your time.
Sincerly,Ross Franklin
MIke here: The values are set according to the telescope model. As to the percents, see the Autostar Information page for some articles on that. As to making an adapter, no specifics for the model but it should be easy to make a mounting plate (metal or wood) that mates to the 4500 and then holds the ETX via the tripod attachment holes on the base.
Subject:	ETX-90 RA Drive...
Sent:	Monday, March 10, 2003 18:28:43
Hey!  I just got a new ETX-90 RA and the drive doesn't seem to work at
all.  I changed the batteries and even though I can hear it "ticking",
the RA axis doesn't move at all, even after 10 minutes or so ( I tested
it a few times).  I've searched your wonderful site but I have found
little that could help me with my problem.  If you have any suggestions,
that'd be great.  Thanks.

Mike here: Is the RA lock engaging? If not (or even if it is) I would suggest exchanging it at the dealer where you purchased it since it is new.


Yeah, it is.  And then I tried it when the lock was off (just to see)
but no result.  The problem is, I got it off of eBay, not an actual
dealer.  I think the warranty is still valid though.  Should I try
calling Meade?  Thanks for your reply.
Mike here: Meade should be able to help if really new. They can also help if used (but it will cost you).

And more:

Sorry about two emails but the other thing is, when you say engaged, I'm
assuming thats locked tight.  I assume this becasue when I turn the
lock, I begin to feel tension, and then it gets fairly loose again, and
then it gets tight again until it shouldn't be turned anymore.  Maybe
thats part of the problem?  Thanks again.
Mike here: Well, you do not want to overtighten as that will prevent the motor from being able to move the telescope AND can damage the locking mechanism.
Subject:	Plossl VS Super Plossl
Sent:	Monday, March 10, 2003 12:04:44
From: (Michael Teige)
I see used or new Plossl eyepieces on the 'Net on Ebay and other places
for anywhere from $9.99 (Ebay) to around $40 (Full Retail).

Ebay usually does not have many Super Plossls and when they do they are
usually not a huge bargain selling for around $50.00 most of the time.

These are about 90% Meade eyepieces.

I know that the Meade Plossls are "specifically designed for use with
ETX 60mm and 70mm models" but what does that mean?

What sort of performance should I expect if I use one in my Meade ETX

For the ETX, Meade seems to be pushing only the Super Plossl line.

What's the difference?

I know the Super Plossls are twice the price of the non-super variety,
but are they twice the eyepiece? With persistence I can pick up on Ebay
an ETX 60mm & 70mm Plossl of whatever size for under $20.

Should I?
Mike here: Well, in general the Super Plossls are better but the difference is somewhat in the eye of the beholder. Depending upon how you use your ETX-90, under what conditions, and what your expectations are, low-end eyepieces may work just as well as higher priced eyepieces. You may see more coma or be out-of-focus at the field edge but if that doesn't bother you then why pay for something better. On the other hand, keep in mind that the weakest link in your optics will show up in your views. The ETX-90 optics are pretty high quality and can benefit from better eyepieces.
Subject:	Re: Tracking Problem
Sent:	Sunday, March 9, 2003 16:02:48
From: (Skip Copp)
I had this same problem.  My problem was that I bumped the N-S selection
switch on the bottom of the mount when I mounted the ETX-90RA on the
tripod and the switch  changed position from N to S.  This will cause
the problem that you described.

S Copp

Subject:	Quick Eyepiece Question
Sent:	Sunday, March 9, 2003 12:11:59
Searched your website section on eyepieces and your ETX book before I
bothered you with a simple question. A friend of mine is giving me his
eyepieces from his ETX-70: Meade # 07136 Plossl 4 mm and Meade 07138
Plossl 6 mm. The boxes say for ETX-60AT & ETX-70AT.

I have an ETX-90EC. The 1.25" OD should fit - I just wasn't sure if
Plossl vs. Super Plossl is a significant issue. I am a "VERY beginner"
with my ETX. Will these eyepieces work okay on my ETX-90EC, or should I

Thanks for keeping-up a great website and for producing your book. I got
iyour book when the first printing came out - it's a great "go-to"
source for all things ETX. Thanks for taking time to write such a great

Thanks for your time.
Gary Dowling
Mike here: Those eyepieces will be OK with other telescopes. Quality is slightly lower, which doesn't matter with the ETX-60AT and ETX-70AT due to the shorter focal length, and probably won't be too noticeable on the ETX-90.


Thanks for the response Mike.

Subject:	RE: Question using ETX-90RA for terrestrial photography.
Sent:	Sunday, March 9, 2003 0:19:25
So is it just vignetting in the viewfinder due to the mirror being too
short (design limitation) or will the negative/positive (chrome) also
show vignetting and have the image cut off?

I know in older Hasselblads this problem would only vignette in the
viewfinder, but the entire negative/positive would be exposed normally.

What do you think? I haven't taken any pictures yet, waiting for s clear
day to do a nice sunset or something like that.


S Ratzlaff
Mike here: The cone of light is such that you will probably see the darkening at all four corners on the film. Also, see Stephen's "Vignetting Check" article on the Helpful Information - Astrophotography page.
Subject:	Question using ETX-90RA for terrestrial photography.
Sent:	Saturday, March 8, 2003 17:01:08
Will you post this to see what others have observed?

I use Canon EOS cameras and have noticed something while using my
EXT-90RA with the cameras attached.

The entire viewfinder is not illuminated, (the top of the image in the
viewfinder has a uniform dark line which is dark, this is supposed to be
illuminated by the bottom of the SLR's mirror. It looks like the
camera's mirror is not long enough to illuminate the entire viewfinder
on the camera. From setting the camera shutter on bulb, I can still see
some light in each corner and edge of the film plane opening.

I haven't taken any pictures yet to see if the entire frame is being
exposed, but from looking at the viewfinder, it appears to be vignetting
in the viewfinder. I know some medium format cameras (older Hasselblad's
for example) have this problem with longer focal length lenses, but have
never heard of this problem in 35mm cameras but suppose it's possible.

I have the 64T (T-64? whatever it's called) attached with a T-mount
adapter and see the vignetting/or short mirror issue ??? using both the
short tube and also the short+long tube of the 64T. The lack of
illumination is very uniform in a fairly sharp line at the top of the

Is this normal when using the ETX-90RA, with T64 on 35mm cameras? This
happens with two different models of EOS cameras.


Anyhow, another question not photography related.

Is it plausible to see M1-Crab Nebula using the ETX-90RA with the
standard 26mm eyepiece? I've tried to find this object repeatedly, and
cannot seem to see it with this setup. Am I attempting the impossible?

Viewing conditions aren't the greatest but I can see M42 and M43 pretty
clearly. And have been trying while M1 is still at least 40 degrees
above the western horizon, there's no Moon visible, but have not been
able to see M1.


Mike here: Yes, vignetting is occurring and it is normal for some cameras and adapters with the ETX. And yes, you can see M1 with the ETX-90. I've seen it with the ETX-90 and remember seeing it with my old Edmund Scientific 3" Newtonian reflector back in the 1960s. You will need reasonably dark skies to see it.
Subject:	Tracking problem
Sent:	Friday, March 7, 2003 14:10:38
From: (Dale D. Penkala)
Hope you can help me.  I bought a new/used etx90 ra and have used it a
couple of times. I polar aligned it quit accurately and I noticed that
the tracking speed is very fast. Even using the 26mm the image don't
stay in the fov for more than 2-3 min's. Max!

I have to keep bringing the scope back east to bring the image back to
center. Also I noticed that when I move to a different object and snug
the ra lock down it doesn't pick back up on the tracking. I have to
fiddle with it. Lock unlock lock unlock etc...

I'm not very familiar with the etx, but am quit familiar with the the
lx200's. I have a 10" and 12" and a 14" on order. I'm ruling out polar
alignment as an issue. I very familiar with that process as well. All my
adjustments are done in ra to bring back the image to center. As I said
this is a 2 1/2 month old scope but I bought it used. It's in LNIB
condition. To bad it don't track well. Any help would be greatly
appreciated. I've ruled out sending back to meade as they fee to fix is
75.00. I'm sure you know that you can get one for 179.00 shipped to your

Thanks Dale
Mike here: Are you using the normal batteries? You might want to see the article "Another ETX-90RA Drive Mod" on the Telescope Tech Tips page.
Subject:	Will the Meade 889 Adapter Plate fit my 90ra?
Sent:	Thursday, March 6, 2003 8:56:44
From: (Fischer, Lyle)
Just wanted to know if the Meade 889 adapter plate (for attaching an ETX
125 to the standard field tripod) will also work with the 90ra.


Lyle Fischer
Mike here: It is not required for the ETX-90 models.
Subject:	question
Sent:	Wednesday, March 5, 2003 12:22:49
From: (Fabiola Leon)
I own a ETX 90 RA telescope and I have the original eyepiece (26mm) I
want to buy some lenses.  But first Id like to buy a barlow lenses, and
I dont know which are better, the #128 3x or de #126 2x for my
telescope.  Can you help me with that?

Does the erecting prisms has their disvantages?

I am a a beginner using a telescope, could you recomend me some
eyepieces for me?


Please e-mail me back.
Mike here: Personally I'd suggest the #126 2X Barlow Lens as I don't like the 3X ones. Beyond that, check the suggestions on the Buyer/New User Tips page. Also check the Accessory Reviews - Eyepieces page. Keep in mind that the maximum theoretical magnification for the ETX-90 is 180X. You can exceed that on bright objects under good seeing but don't count on it on a regular basis.


Another question.  

I read that the ETX-90 RA came with a software but mine didnt bring it
when I bought it :(.  Do you know where I can buy it or download it?

Mike here: I don't recall that the ETX-90RA model came with software but if it did it was "planetarium" software. There are many commercial, shareware, and freeware applications like this; see the Software section of the Astronomy Links page.
Subject:	Motor problem on ETX 90EC
Sent:	Monday, March 3, 2003 16:06:17
From: (Malene & Peter)
I hope you can help me. I have a problem with motor failure on my new
ETX 90EC (with Autostar). When I use it, it sometimes suddenly drop at
the alt/dec axis at max speed (after use between 5-30 minutes). It is
doing this with the motor on and at max speed. It does not always do it,
and on a few occasions it has been giving the "Motor Unit Fault"
message, but normally it just drives the scope down, and then keeps
tracking. By the way, it only happens during tracking and not in the
middle of going to another object. I have tried using it on batteries,
and then everything is going just fine (but I have just tried this
approximately 3 hours). The problem is when I use my AC adaptor (from
Meade). I have read that the adaptor could cause this problem, and I
have changed it, but the same problem is happening with the new one.

I have tried observing how long time it goes before the failure comes,
and I found something interesting. The observations are a follows:

Time of use before failure occurred

 17 minutes                            observing Rigel
15 min                                  observing Rigel
23 min                                  observing Rigel (displayed "Motor Unit Fault)
5 min                                    observing Rigel
5 min                                    observing Rigel
18 min                                 observing Rigel

No Failure during use (just switched off the scope after using it)

30 minutes      (observing ???)
15 min            (observing ???) On Batteries
35 min            (observing: Jupiter and Rigel)
70 min            (observing: Pollux (30 min), Betegeuse (25 min) and Rigel (15 min))
35 min            (Saturn)
30 min            (Saiph)

The thing is that it is only while observing Rigel that the problem
occurs?! I don't know if it makes any difference?

My question is basically; What should I do? Try a new adaptor? I don't
know if the adaptor is the problem, there is no particular system in
when the failure occurs. I have checked the adaptor and cord, and can't
find any problems with it. By the way, I have also tried twisting it
under use to see if it made any reaction, but there was none. Could it
be the Autostar?

Anyway, I would really appreciate your advice and help.

By the way, I'm form Denmark in Scandinavia, and therefore English is
just my second languets, so I apologize for any spelling mistakes or
comprehension errors.

Great website you have made. It's nice to know that you only need one
site when looking for something to the ETX. Thanks.

Peter Madsen
Mike here: Glad you like the Site. Thanks. I would suggest doing a CALIBRATE and TRAIN. It may be that the Autostar has lost the calibration. If that doesn't solve the problem, do a RESET, and then CALIBRATE and TRAIN. Be certain to TRAIN both axes when training. You should also check the connections. You didn't specify what Autostar ROM version you are using but if not reasonable current (2.6Ed is current) then I would suggest upgrading via the #505 cable and Meade's web site.


Thanks for your quick response to my questions. To answer your
questions; yes I have tried calibration and training. I have read your
excellent Telescope Tech Tips, and have followed your advice. The
Autostar is version 2.6Ed, I just forgot to mention it.

Today I went to the dealer and got the scope and Autostar changed to new
ones. Haven't really tried it yet, so don't know if the scope was the

By the way, I have been reading that some people have used an adaptor
with 14-15 volt instead of the 12 volts the Meade AC Adaptor supplies,
and something about that the long and thin cord on the adaptor can cause
problems!! Don't know if it is a common problem, but I still suspect
that my problem is related to the AC Adaptor.

Anyway, thanks for your time and help. It is very much appreciated.

Still love your site. I'm currently reading your section about
"Observational Guides/References". Great reading for days with bad


Peter Madsen

Subject:	ETX upgrades
Sent:	Monday, March 3, 2003 12:50:35
From: (bets)
We have an ETX Astro Telescope. It does not have tracking.

We have a Mac Powerbook G3 laptop.

Is there optional equipment which converts the operation from manual to


We have a web camera.  I remember getting instructions on how to
connect the ETX with the laptop for live pictures.  What is that

Many thanks,
Betsey Lawrence
Mike here: You may be thinking of the "JMI NGC-microMAX/NGC-MAX" (see the Accessory Reviews - Miscellaneous page). Short of getting an EC model with an Autostar or something other mount, it is the only way I recall of computerizing the ETX-90RA model. I don't even know if JMI still makes it. As to webcam use, try the Helpful Information --> Astrophotography page.
Subject:	ETX 90RA adjustable middle leg
Sent:	Saturday, March 1, 2003 13:31:49
From: (Bill Batchelor)
Concerning the problem that the UK user has with adjusting his ETX for
UK latitude dated 22 February.  When I purchased my scope from the main
UK dealer, it included another adjustable leg to suit higher latitudes. 
It is a lot shorter than the standard leg, and does not have any degree
markings; so you have to use a suitable method to polar align.

Bill Batchelor, Hertfordshire
Mike here: I had forgotten that Meade used to have a High Latitude Leg for the ETX-90RA.
Subject:	Re:  RE: ETX 90EC
Sent:	Saturday, March 1, 2003 12:31:24
From: (Richard C Jones)
Thanks for getting back to me. I tried your suggestion, still no luck.
Called Meade and they said something inside the scope must be broken. So
I returned it to Berger Brothers today and upgraded to the 105. I hope I
have better luck with 105,my 70 was troble free, you never know. BTW
great prices at Berger Bro. $399 4 the 90, 599 4 the 105 and 699 4 the

Tghanks Again.

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