Last updated: 30 August 2003
This page is for user comments and information specific to the Meade ETX-90RA (originally known as the "ETX Astro"), the ETX-90EC, and the ETX-90AT. Comments on accessories and feedback items appropriate to other ETX and DS models are posted on other pages. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me and I'll post them. Please use an appropriate Subject Line on your message. Thanks.

Subject:	EXT90EC
Sent:	Friday, August 29, 2003 21:22:35
From: (Mike Hubbard)
Nice site, I hope you can help. I purchased a EXT90ec. I have a 9.7mm,
barlos  and a 26mm.  This is the first time I have really used the
scope. When I looked at Mars with the 26mm all I saw was a very small
bright light, I put the barlos on with the 26mm and all I saw was the
small bright light a little closer. I then tried the 9.7mm and the
bright light was a little closer but not what I expected. Maybe I'm
expecting to much. I thought I'd be able to see a fairly good view of
Mars, but all I see is a small bright light. Am I doing something wrong?
I not sure if my scope is broken or I'm just in experienced.

Thanks for any help.
Mike Hubbard
Mike here: I suspect you were expecting too much. See My Astrophotography Gallery - The Planets page for some comparison photos that were taken 15 July.
Subject:	ETX case and right angle finder
Sent:	Friday, August 29, 2003 18:19:56
From: (Jeff Nash)
Love your site and have been using it for years! I have recently meet
Jim Abbey through your site.

Do you know if anybody has come up a good fix for using the Meade ETX 90
with the right angle finder and the Meade case?

Jeff Nash
Mike here: Don't recall any, other than making a cutout.
Subject:	etx info
Sent:	Friday, August 29, 2003 17:16:10
From: (Gregory Walker)
Hi I was just looking over your site just wanted to thank you for all of
the telescope information

I have a meade etx 90ra and I was looking for info on how to convert it
to use the computer control

thanks again I have a mac g4 with ichat can find on line
some time
Mike here: See the FAQ page. Your alternative is to another mount; see the Telescope Tech Tips page. And hope to chat with you sometime.
Subject:	ETX 90EC Right Tube Adapter
Sent:	Friday, August 29, 2003 07:35:23
From: (David Foradori)
I have a question for you.  I own a ETX 90EC and my right tube adapter
has broken.  I was searching the internet and came across They said they sell a lifetime guaranteed aluminum
Right Tube Adapter. So I tried contacting the person with the link on
their page to order one, but unfortunately I received an error for his
email address not working. Anyways, do you know about this, is this
still available, is it a wise choice to use it, or should I just order
another plastic one from Meade? Thanks in advance for your time and info
on this matter
Mike here: Scopetronix was selling them for a limited time. Don't know if they have any left. I'll forward your email to them.
Subject:	Should I buy a ETX-90EC??
Sent:	Thursday, August 28, 2003 19:34:27
From: (Andrea Visacovsky)
My name is Andrea and im from Argentina. 

Some time ago I sold my telescope, which was a Celestron Firstcope 76
and now I want to buy a better one. Ive been asking everybody to help me
to choose the best one, or at least, the best one for me according to my
conditions (location, sky, money..etc.).

Thats why many people recommended me buying the its
portable, light and the optics was great.However, im not sure about what
to today a Meade dealer tried to show me all the disadvantages
that this telescope has. So, I was hoping if you could help me by
telling me why I should buy this one, if im gonna have a better view of
the deep sky objects and which telescope may be better if i have to
choose between the ETX-90 and the new meade telescope DS-21114ATS (which
I think was released as a way to compete with the NextStar series,
especially the one of 114 focal lenght).

Well, that`s all. I hope you can understand my English...


Andrea (from Buenos Aires)
Mike here: Which telescope is right for you depends upon several factors but the BEST telescope is one that gets used vs sitting in the closet. You need to decide on how you want to use a telescope, whether portability or aperture/focal length is important, features, and cost. Read through the User Observations page to get an idea of what ETX model can do. Don't just look at the astrophotography galleries as photos do not always compare to what the eye sees.
Subject:	ETX-90AT vs. EC?
Sent:	Thursday, August 28, 2003 15:01:56
From: (Kelly, Bob)
I'm about to purchase an ETX-90, but I can't determine whether the AT
and EC versions are different.  Something I read gave the impression
that the AT is newer than the EC, but what are the main differences
between the models? When was the AT introduced?

If they are different and the AT is newer, the EC still seems to be for
sale at quite a few places.
I found the answer on your site!!  Sorry to bother you with a redundant

Great site, by the way!



Subject:	Neophyte needs some advice
Sent:	Thursday, August 28, 2003 10:52:53
Hope you don't mind me emailing you.  I've recently purchased a Meade
ETX 90RA telescope, my first scope and I'm a little bit clueless as to
exactly how to use it.  I have it mounted on a tripod and have been
trying to view Mars but it appears that when I focus on it the image is
no better then I can see with my naked eye?  Am I doing something wrong?
 I notice that when I change the focus I get a white halo around the
image and it gets this actually focusing / magnifying the
object?  I'm hoping you can give me a clue as I"ve looked everywhere
online for the answer to my questions.
Mike here: You are making a common new-user error. You use the focus knob to bring the image into focus, not to magnify it. When Mars is in focus, it will be as small as possible. What you need is more magnification (up to the limit of usable magnification for the ETX-90 (around 200X but you can exceed that on bright objects under good seeing conditions with good optics).


Hey, thanks a bunch Mike...after I emailed you I actually found a
reference to this phenom on your web site bulletin board.  Let me ask
you this...what would lens would you suggest I purchase and where might
I get these?  I heard a 2x barrow? lense for a start and then what? 
Thanks for your help...  and bye the way, how much longer is Mars going
to be "hanging around"?
Mike here: See the Buyer/New User Tips page and the Accessory Reviews - Eyepieces page some eyepiece suggestions. Yes, a Barlow Lens can be useful but if you get one be certain it is a "shorty" model so that it works with the ETX-90. Mars will be "hanging around" for a few billion years more... But the current good viewing will continue through at least September but the distance between the Earth and Mars is getting larger.
Subject:	ETX-90EC Gear Assembly Problem
Sent:	Thursday, August 28, 2003 04:46:36
Last night my telescope developed a fault which I am
afraid might cost me a fortune. Whilst slewing to Mars, the
telescope mechanism started "knocking" and there was no mevement
whatsoever on the azimuth gear. Since my guarantee from Meade has
expired, I opened the bottom and inspected the gears, and it seems that
the gear black mechanism to which the motor is attached keeps slipping.
The motor turns normally, but it seems the gears are misaligned or
something. After taking the assembly apart,  and inspecting the
gears, I noticed that none of them look worn.

I am thus wondering whether I could substitute the motor and gear
mechanism with the that of an ETX-90RA which I am planning to use
as a donor. I have already located a cheap, new ETX-90RA drive
base, only I need to resolve the compatibility issue before I procced to
purchasing it. From pictures I have see of both drive bases, the
mechanisms look identical. Do you have any information as to

Shipping the telescope back to Meade is definitely not an option due to
the astronomical costs of courier delivery, rendering its repair
uneconomical. Needless to say, the Meade representative in Cyprus does
not want to know about  a telescope that was purchased direct from
the USA. (just to let you know, the guy sells a basic package ETX90EC
with no accessories for $800+)

Thanks ever so much for your kind attention and looking forward to your
reply. Buy the way, thanks for your site, definitely a Godsend!

Phivos Hadjigeorgiou,
And from our resident hardware expert:
From: (P. Clay Sherrod)
The ETX RA model is not compatible with the ETX EC models at
all...totally different workings and not at all alike.  The drive
assemblies from the 125 and 90 EC models can indeed be interchanged, but
the hardware in the RA model will not do you any good whatsoever in any
EC model.

Dr. Clay
Arkansas Sky Observatory
Petit Jean Mountain
Harvard/MPC H41
Dear Mike,
Thank you for your speedy reply and comments on the ETX90-EC problem I
have. Upon closer inspection last night (grease removed from the
internal gear assembly) I discovered that the teeth on one of the gears
are worn, thus causing the slippage.

As far as the RA drive assembly is concerned I had already bought it by
the time I got your mail (time difference I guess - I am at GMT +2 here)
so I will just have to wait until it arrives to assess compatibility,
though Dr Clay has advised that the assemblies are not
interchangeable. Other photos on you site though, indicate to the
contrary (attaching the picture of the RA drive assembly innards here).
Anyway, the cost of purchase was really low (40 US for a new assembly)
including a new table tripod that I don't really mind making a
sacrifice at the altar of science. In the meantime, I will contact
Meade and try to get them to send me either the azimuth drive assembly
as a whole or the internal gears to replace on my own. I figure that
will take a lot of imploring as I bet they will not be happy at the
thought of one of their customers taking a screwdriver to one of their
creations. But I like to think of myself as a good DIY man.

Thank you ever so much for your help, it is much appreciated. Save this
email somewhere if you like, as I will follow up with this so the
information can be shared with other ETX owners who may have the same


Subject:	Meade ETX telescopes
Sent:	Wednesday, August 27, 2003 08:10:09
From: (net walker)
hi. i just got done looking at your site and you seem to be the most
educated ETX person in the free world. i am at or near the other end of
that spectrum, being possessed of as little knowledge in regard to my
telescope as is humanly possible. anyway, last night i was out looking
through my ETX at mars, and i have a couple of questions about the
telescope. first off, i have just a plain ETX. it doesnt have all the
numbers behind it like all the ones i have seen online. i dont have the
computer controls, or even a place to plug them in! mine came with one
eyepiece (a meade super plossl 26mm multi coated eyepiece) a lens cover,
and the legs that screw into the base. with batteries, mine will track
automatically, but it isnt like it knows where it is going, it just
turns the motor at a speed in relation to the earths rotation, thereby
keeping the object in view, at least in theory. now my question is, when
i get mars in view, and then go to focus on it, i am getting a big black
spot right in the center of mars that i dont think should be there. it
gets bigger as i increase the magnification, and i have cleaned all my
optics, so its not that. do you have any ideas on what i might be doing
wrong and how to corrrect it? i have a camera that i can attach to the
back of my ETX, but i really want the spot to not show up in my pictures
as well as being able to get a clear view from the eyepiece. if you have
any suggestions i would greatly appreciate anything you can tell me. oh,
and will any ETX eyepieces work with my model? the meade website doesnt
even call out my scope in their catalog.


cary kelley
Mike here: You have the original ETX model (which I also have), which has been discontinued but still sold. It is now known as the ETX-90RA (and some other names). You are making a common new user error; you are using the focus to make the image as large as possible instead of using it to achieve as crisp a focus as possible. For the planets, in-focus means the image will actually be as small as possible. Since you just have the 26mm eyepiece, your magnification is limited and you will need more to get a better view of Mars. You will want to look for something shorter than about 10mm for the eyepiece (or get a 2X or 3X Barlow Lens, a "shorty" model for the ETX-90).
Subject:	Meade ETX90EC vertical axis
Sent:	Wednesday, August 27, 2003 06:27:56
I have the same problem with the vertical axis (move left-right). The
motor is spinning, you could move the telescope from left to right, but
the telescope is not moving.

Did you manage to fix the problem?

Ralf Schulz, Hong Kong
Von:     lehuron (
Not completely. As Mike suggested, I rotated the ETX manually and with
the motor, from one end stop to the other and back, for long periods of
time, and the motor managed to rotate the tube, but in many occasions I
have to push the tube to start the movement.
My ETX does not move at all with the motor. I can turn it manually, but
it seems if the clutch does not engage.

Subject:	Etx
Sent:	Tuesday, August 26, 2003 23:26:38
From: (diane marince)
I am about to buy an ETX. I want to view terrestial subjects (wildlife
at Yellowstone) as well as astronomical objects. I am new to this. It
the etx 90 a good choice for both? Or perhaps one of the other etx sizes
would be better suited. If not, then I could buy a spotting scope, and
pick the ETX for astro viewing only. Thanks.....Diane M
Mike here: The ETX-90 makes a nice spotting telescope. It can be easily removed the fork arms and mounted on a tripod or, with proper attachments, used as a 1250mm telephoto lens. It is very portable (will fit into a backpack). Search the site for "birding" or "terrestrial" and you'll get some hits.
Subject:	etx astro telescope question
Sent:	Tuesday, August 26, 2003 22:55:51
From: (larry hinkle)
i have an etx astro telescope (just like the one in your photo), which i
purchased in 1998. i've always had wonderful views of jupiter, saturn
and the moon, but never satisfying views of mars. i haven't used it much
lately, but with all the recent talk about mars, i had to get it back
out. i went out back to check on mars tonight, and was really
disappointed. it looked the same now as it did back when i first got the
scope. i have the original lens it came with (meade series 4000, 26mm lp
super plossl, 1.25" o.d.), along with a barlow x2. is the standard lens
on the astro scope just not capable of giving good views of the red
planet? or is the etx not as good as the guy at the discovery store told


larry hinkle
Mike here: Actually, the view is better from a size point of view this time around. Mars is physically closer to us. But your expectations may be too high for the limited magnification you've tried. Get your hands on an eyepiece shorter than about 10mm; that should improve the view.


thanks for getting back to me so fast. i read the eyepiece section on
your site, and followed a link to the scopetronix site. they have a
Scopetronix 9.0mm ST Series Plossl (STPL09) for $37.95, and a Meade
9.7mm Super Plossl (MSP097) for $79.95. is there going to be a big
difference between these two eyepieces, or should i stick with the meade
since i have a meade scope? also, can i use a generic tripod for my etx,
or do i need to get the meade tripod, which is almost $200? (i don't
have a ton of money to sink into this, so i'm trying to maximize my
purchases to keep my wife happy.)

btw, i live in colorado springs, and the local astronomy club had a mars
viewing party last night. there were over 1,000 people that showed up
over the three hours (8-11 mst), but the clouds never parted and we all
went home disappointed.

again, thanks for your help. i really enjoy your site, and hope to start
enjoying my telescope again as well.



p.s. the scopetronix site has a link to your etx site.
Mike here: For the ETX-90 you probably won't notice much difference. Although if you add a Barlow Lens to the 9mm vs the 9.7mm you probably would get a slightly better view through the Meade one. As to a tripod, be certain it is a sturdy one. Otherwise vibrations will drive you nuts and making viewing impossible. See the Telescope Tech Tips page for lots of tripod info.
Subject:	ETX Woes...??
Sent:	Tuesday, August 26, 2003 20:32:05
From: (Barney Green)
Well we got the scope out to check out Mars tonight, it appears that the
little cone inside of the back of the lens on the front has 'moved' a
bit.  Like the Adhesive has been warm or something.  That can't be, as
this baby always is in the house when not being used.  It's the original
ETX Astro Telescope mentioned on your site.

So, I proceed to unscrew the front lens and try to just move the thing
back in place. not much luck.   I then proceed to unstick it and replace
it correctly.  It seems to have worked ok.

I was wondering if you ever seen this before, and what is the real fix.
(or does it even need to be there)

Thank in advance. wonderful site BTY.  I've looked at it for years.

Kind regards,

Barney Green

Chapel Hill, NC
Mike here: Check this page:
Is this what you see? As to trying to fix it yourself, see the article "ETX-90RA Secondary Baffle Fix" on the Telescope Tech Tips page. But you might prefer to contact Meade.


Thanks for the help.  I give it a shot... ( and I'll probably call Meade
first) ...

Thanks again for a great site...

Kind regards,


Subject:	ETX-90AT??
Sent:	Monday, August 25, 2003 22:21:26
From: (Matt Riggins)
My name is Matt Riggins. I run a small Mac computer consultancy in Los
Angeles. My brother bought me a Meade EXT-70AT telescope last December
and its been great, my first scope. Ive enjoyed using it, but am excited
about Mars being so close this Wednesday.

Now I know that living in L.A., there is a little city light problem ,
but despite the issues of living in the city (Im heading to the Mojave
desert Wednesday btw) I want to upgrade to a bigger scope, so here goes
my questions.

Is it worth going from the ETX-70AT to the EXT-90AT? Is the difference
something like going from an iBook G3 to a Powerbook 17 G4? Or, is is
like upgrading your ram from 128 megs to 512 megs? I guess what Im
asking is, for an upgrade is the 90AT going to give me a substantial
difference then my 70AT?

Also, what do you think about the DS-2114 ATS scope? I dont know much
about scopes, so Im hoping you might be able to give me a comparison. A
local store to me has it listed at

At any rate, any and all info you could provide would be extremely
helpful and thank you!


Matt Riggins
Mike here: I have no experience with the DS models but a larger aperture and a longer focal length will yield larger and more detailed views than the ETX-70 provides. That's also true of the ETX-90. The ETX-70 is a short focal length telescope (350mm) vs the 1250mm focal length of the ETX-90. Of course, the ETX-90 is more portable than the DS telescopes. Moving from the ETX-70AT to a 16" telescope would be like moving from an iBook to the PowerBook 17".
Subject:	Best lens to use to view Mars?
Sent:	Monday, August 25, 2003 15:41:58
From: (Delafuente, Rene USA)
What do you recommend I use to view Mars to see its polar caps?  I
currently only have a 26mm on my ETX90EC and I can only see a small
bright yellow circle.  Folks on television say one should be able to see
the polar caps rather easily.  Am I doing something wrong or do I need
to buy a more powerful eyepiece?  I would appreciate your
recommendations before I go and purchase an eyepiece so as not to make
mistakes.  Thanks in advance.
Mike here: You definitely need more magnification. You will want to get as close to the theoretical maximum (about 180X for the ETX-90) as you can for your viewing conditions. You could add a 2X or 3X Barlow Lens (you need a "shorty" model for the ETX-90) or you could use shorter focal length eyepieces. If you are uncertain how to calculate the max magnification and magnification values, see the FAQ page. Right now the South Polar Ice Cap is easily visible but it has been shrinking in size a lot since July (it is Summer in that hemisphere on Mars).


Thanks you very much for responding Mike.  I also surely appreciate the
quick response.  I'll be going out today to purchase a 7.5 mm eyepiece
and am hoping that will give me an eyeful.  I'm decided on a 7.5 mm but
don't know if I should go for a 50degree or higher field of view.   Or
as you suggest, perhaps I could just buy a Barlow but I'm so confused
now.  Thanks again and I'll continue to read up on your website.

Sent:	Sunday, August 24, 2003 21:17:03
From: (Ron and Liz Tobeck)
I am new to Astronomy and just purchased my first telescope - an
ETX90EC.  I also purchased a Meade 13.8mm wide angle lens, a 18mm wide
angle lens, a 32mm Super Plossl, and a Celestron Ultima 2x Barlow. 
These last few nights I have tried to observe Mars but all I get is a
small shiny blob with no discernible features. Should I have more
powerful lenses or am I just expecting too much. I had been hoping to be
able to see at least some features. As it is what I am seeing is only
slightly more than what I see with my Bushnell Spotting scope.  Any help
or recommendations would be much appreciated. Many thanks.

Ron Tobeck
Mike here: You may be expecting too much, especially if you expect to see details like you see in some of the photographs. Of course, there are many factors at work to influence what you see or don't see. Mars is low in the south for many locations in the Northern Hemisphere so our atmosphere messes up the view. Your location conditions can also mess up the view. Not letting the telescope reach "thermal equilibrium" with the outside temperature will also influence the view. And right now there is not a lot of highly visible features on Mars other than a broad dark area in the Southern Hemisphere and of course, the still shrinking South Polar Ice Cap. Check out My Astrophotography Gallery - Planets for a comparison of Mars through different telescopes. While the viewing was lousy when I took the photos, they do provide a good indication of size.
Subject:	ETX 90EC
Sent:	Saturday, August 23, 2003 21:27:33
From: (Soula Rothchild)
I have an ETX 90 EX, with a 497 Autostar.  I have not used to Autostar
for over 2 years. Does it need some sort of "update", and if so, How is
this done?

The accuracy wasn't exactly 100%, perhaps more like 75 to 80%.  Is this

Another big problem, was that I select a deep sky object, such as the
whirlpool galaxy, and after slewing to this selection, nothing, at least
that I can see at 48x, was in view.  How do I know it was even correct
in pointing in that direction, and is it pushing the limits of this
scope to see deep sky objects, such as other galaxies and globular

Please advise and thanks,

Neal in Cincinnati
Mike here: There have been some updates in last couple of years so updating should be done. You need to buy or make a #505 cable (details for making on the Autostar Information page). You will also need Windows and a serial port. For more info, see the Autostar Information page. Yes, you can see some DSOs with an ETX-90 but your local sky conditions will affect what or whether you can see any particular object. So will your eyes; they will need to be well dark-adapted and you might need to use "averted vision" (look to the side of where the object is not AT it). You might want to look at the Telescope Performance articles on the Observational Guides/References page.
Subject:	ETX-90 Newbie problems
Sent:	Wednesday, August 20, 2003 07:12:41
From: (Jim Fisher)
You have a great site.  Have been reading it for a while and finally
decided to buy an ETX-90.  I am a complete newbie to Astronomy.  About
the only thing I can find in the sky is the moon. Took it out for the
first time last night with the Autostar controller.  The light pollution
to the north of me obscures about 25-30 degrees of the horizon so was
not able to find the big dipper around 11:30pm EDT (I am about 35 miles
south east of Washington DC). Not sure how high in the sky it is at that
time.  I followed the setup instructions: First I turned the ETX
counterclockwise until it reached its stop.  Then I turned it clockwise
until the fork arm with the Dec scale was over the controller hookup. 
Moving the 884 tripod, I pointed the ETX north using a compass and had
the Dec set at 0.  Using the 26 mm lens that came with it.  During the
alignment for the first star, the ETX turned more than 360 degrees
before coming to rest on the first star of the alignment.  When I
looked, all I could see was a star field so I have no idea which star I
was suppose to be aligning with.  No star stood out so I just stopped at
that point since I had no idea what to do after that.  Can you tell from
my description if I did something wrong?  I also saw a bright object in
the south eastern sky which I moved the ETX manually to view.  Do you
know if this is Mars?  It was also just a bigger point of light in the
ETX.  How do I get to see more details?  That is why I bought the ETX. 
Thanks for any help you can provide.

Mike here: From your description, it sounds like the only thing you may have done wrong during the alignment is to use Magnetic North instead of True North. You can use Polaris as an indicator of where True North is. There are alignment charts on the Autostar Information page; they should help you pick out Polaris and the alignment stars. Also, you might want to read over some of the alignment tips on that page. And yes, that bright object in the southeast before Midnight is Mars. If you only have the 26mm eyepiece you will want to get more eyepieces and/or a 2X or 3X Barlow Lens to increase the magnification. However, keep in mind that the ETX-90 is limited to about 180X except under really good seeing conditions and then only on bright objects (like the Moon and the brighter planets).


Thanks for getting back to me.  I bought a star chart yesterday and
tried it last night.  I think part of the problem is that the light is
washing out a lot of stars.  I think I found the big dipper but not sure
since I could not see any stars in the area where the handle should be. 
I guess I will have to go to a darker area.  I read through some of the
Autostar information yesterday but need to go through the rest.  Last
question, do you have any recommendations for brand/size of eyepieces? 
Also wanted to let you know that I ordered your book yesterday from
Amazon.  Anixious to get it.  Thanks for your help.

Mike here: See the Accessory Reviews - Eyepieces page as well as the Buyer/New User Tips page for some ideas. Keep in mind that the better the eyepiece the better the views. But personally I would not spend more on an eyepiece for the ETX-90 than I did on the telescope unless you plan to get a larger telescope some day soon.
Subject:	Re: Finder scope hits the fork on ETX-90EC 
Sent:	Sunday, August 17, 2003 23:01:53
From: (Stan Glaser)
Reading David's e-mail about his finderscope hitting the fork brought
back memories of the same for me on my ETX-90RA model (which has since
been sold and replaced with the -90EC). I had the original straight-thru
finder, and I made sure the OTA was level AND the DEC scale was set to 0
degrees. When the OTA was rotated to 90 degrees, part of the bracket hit
the fork, so I never could get the scope into a good polar alignment. I
tried moving the finderscope forward and backward within the mount to
see if I could clear it, but to no avail. I finally took some very fine
sandpaper and neatly and carefully sanded down some of the fork arm
where the clearance was needed, and was then able to rotate the OTA to
its full 90 degree orientation. Of course, about a week after that, I
discovered that JMI was selling a 90-degree finderscope conversion kit
-- at the time, a god-send idea that Meade should have thought of BEFORE
releasing the RA model (ah, hindsight!). After installing the
conversion, not only did the OTA rotate to 90 degrees, it actually went
even more!!

Stan Glaser

Subject:	Question on ETX90
Sent:	Sunday, August 17, 2003 19:00:10
From: (Nestor Dutko)
Do you know the size of the hex wrench required for removal of the ETX
OTA? I can not locate the wrench and am having problems with the
vertical lock not holding.


Mike here: Looks to be 3/32".


Thanks Mike - as it turns out, I had a 3/32 one and it was too small. I
picked up a set of hex wrenches in 1/64th increments. Its actually
Mike here: Oops. My measurement was off by 1/64th!


No prob. Figured I would pass the info along in case someone else asked.
Even Meade when asked gave me a different value (5/32). You were much
closer ;-)

Subject:	etx
Sent:	Sunday, August 17, 2003 10:22:06
From: (Steve Dunlap)
hey, i just purchased a etx90EC and love it.  what is the best sized
eyepiece for the upcoming mars viewing?
Mike here: You will want an eyepiece that gets you to about 150X. 180X is the theoretical maximum magnification although you can exceed this with good seeing on bright objects. Depending upon how high in the sky Mars gets at your location, you may or may not have good seeing for viewing it. Anyway, a 8-9mm eyepiece will get you in the right area. But you will likely do better with a 12mm eyepiece or a 2X Barlow lens if you only have the 26mm eyepiece.
Subject:	ETX90-RA with Microstar II Controller
Sent:	Thursday, August 14, 2003 05:36:53
From: (Andrea Perfetti)
I own the fantastic Microstar II from Scopetrinix which has been the
greatest add-on to the little great 90RA. Howewer the controller has now
developed a fault and I'm wondering if any of your readers has come
against it too and has solved the problem.

The controller lights up ok and tracks well on RA axis but after a
minute or so it suddenly starts moving north on the DEC axis and the
only cure is to unplug power to the DEC motor.

Cabling is ok and for sure is not a problem with the push buttons. It
seems that one of the two tiny potentiometers for speed adjusting has
become a little black in the center.

I wrote to Scopetronix too.
Any help or schematics is very welcome.

Keep up the good work
Andrea Perfetti
Mike here: I have the Microstar II+ and love it. No problems here and I don't recall any reports of problems. Let me know what you hear from Scopetronix.


Jordan Blessing just wrote to me: they have some spare parts and will do
their best for my unit at no charge! Wonderful!!!

I love the Microstar too and can't only think to loose it. Scopetronix
proved to me again to be the best company to make business with.

Andrea Perfetti

Subject:	Possible problem with ETX secondary baffle
Sent:	Thursday, August 14, 2003 05:27:34
From: (Gary Prentice)
I have one of the original ETX-90 scopes that I bought in 1998. Lately,
I have noticed that the baffle behind the silvered spot on the meniscus
lens looks like it has shifted. When you look at the spot, you can see
that the baffle is not precisely aligned with it.

It almost looks like the baffle has slid down a little due to gravity
over time. Have you ever heard of this problem before? I haven't used
the scope for a while and it's possible I'm imagining the problem but I
don't remember it looking like this. The telescope seems to still
perform OK.

I have CC'd this message to Dr Clay also. I would very much appreciate
any advice either of you can give. Thanks.

Best regards,
Gary Prentice
From: (P. Clay Sherrod)
Very common problem and there IS a fix posted on the Mighty ETX web
site!  I repair these very often and it is tricky...patience is the key
here.  Go slowly and allow plenty of time to dry.  Best of luck!

Dr. Clay
Arkansas Sky Observatory
10 Observatory Hill Drive, Petit Jean
Harvard/MPC H41 (Petit Jean Mountain)
Harvard/MPC H43 (Conway)
Harvard/MPC H44 (Cascade Mountain)
Mike here: I had this problem with my ETX-90RA almost four years ago. You can see the photo on the "Meade Facility Tour" article in the Just for Fun area.


I have found more info on your site and will think about what to do.
Dear Dr Clay,

Thanks very much for your quick reply regarding my baffle problem. I
have found more information on Mike's web site and will consider doing a
repair. Not a very satisfactory situation - I would have expected Meade
to have secured the baffle in a much more permanent way.

Anyhow, thanks again for your reply.
Best of luck; take your time and pretend you are repair a fine old Swiss for me every time.

Dr. Clay
Mike here: There was a "glue" problem on the original ETX model. I think that has since been resolved.
Subject:	Finder scope its the fork on ETX-90EC
Sent:	Wednesday, August 13, 2003 20:47:21
From: (David Morlan)
I purchased a used ETX 90,  this is my first scope.  When I try to point
the scope to 90 degrees (as you would for polar alignment) the finder
scope mount hits the fork about 1-2 degrees before the it aligns with
90.  Is this normal for this scope or has my scope been assembled
Mike here: What type of finderscope do you have? Is the standard (for the -90) straight-through or is a right-angle one? If the latter, try rotating it in the bracket.


I have the standard straight through finder.  It is not the finder but
the bracket itself that hits the fork.
Mike here: The bracket itself or the screws holding the finderscope inside the bracket? If the latter you could probably get shorter ones from your local hardware store.


It is the bracket itself.  I am going to go by the store and see if it
is the same on the ones they have.  If their do not have the same
problem I should be able to figure out what is different.
Mike here: Let me know. The bracket on my ETX-90RA clears the fork just fine.

And an update:

I went and looked at a scope at the mall (Discovery Store) and it had
1/4 inch of clearance when the scope was positioned at 90 degress (likke
for polar alignment).  In this position mine appeared to have and
interference between the fork and the bracket.  I cam home and leveled
everything and it tunrs out that my Dec Circle (not sure I have that
right) is off by about 4 degrees.  When the scope is perpendicular to
the base of the scope the Dec Circle is reading about 86-87 degrees and
there is no interference.

Bottom line is my scope has clearance but not nearly as much as the
other scope I looked at.

Thanks for the help.

I have only been at this for about a month (been cloudy the whole time)
and have spent many, many hours on your site.

Keep up the great work!
Mike here: Ah ha, the DEC/Altitude scale is off. See the FAQ page for how to adjust it. Generally you won't be slewing past 90 degrees.
Subject:	ETX 90 mechanical problem
Sent:	Tuesday, August 12, 2003 01:16:22
From: (lehuron)
I have an ETX 90, bought in Florida  about the time when the Autostar
was produced (I bought one later on).

I have not used it much, as I could see so much more in my C8, and the
Autostar was a bit disapointing. (Lack of precision)

But now I have a real problem : the telescope won't respond to the
azimut motor. I have the noise, but not the motion. I have to help him
by hand and the Autostar seems erratic.

This could not be a voltage problem, as I use a transfo, and checked the
voltage while in use.

I took of the basis and checked : the tangent screw and wheel operate
normally, the wheel turns (or is it revolves ?) but the telescope does
not follows.

Can you give me an advice ? (Other than go to the importer !) The Meade
dealers in France are real killers, and as my scope was bought in the
USA they would really take my skin and bones apart !

Thanks in advance
Alain Gliksman
Mike here: Could be a couple of problems. If the telescope has been unused for a long time then you might need to redistribute the grease. Unlock the azimuth axis and move the telescope from hardstop to hardstop, back and forth several times. Then lock the axis and try slewing with the hardcontroller. Does it slew more smoothly now? Your lack of precision with the Autostar may indicate that you need to reTRAIN the drives. If you have never updated it, I suggest you do that as well (you will need a #505 cable, Windows, a serial port, and the Meade Autostar Updater Application from their website).
Subject:	ETX-90EC Mars Viewing Help
Sent:	Monday, August 11, 2003 04:42:17
From: (Nalin R. Jain)
I am a novice at astronomy. Bought my Meade ETX-90EC new in 2000; did
not add or buy any accessories - using it just the way it came.

I must say I am a tad disappointed with the viewing results. With so
many folks praising their ETXs, I am wondering if I am doing anything
wrong or missing something. Last year I looked at Saturn and could
barely make out the rings. The planet itself appeared as a very small
blob. This year I am eying Mars and the planet appears as an even
smaller blob - very small, clear disc but no surface features are
discernible. Even when viewing the moon, I do not see the features many
ETX owners have said they do.

What gives?

Thank you for your assistance and congratulations on getting a spelndid
site going on for this long. Keep it up!

Mike here: Since you have only the 26mm eyepiece your views are limited to that magnification. You'll need more eyepieces or a 2X or 3X Barlow Lens to get more out of your telescope for viewing the Moon and planets.


You are wonderful! Thanks for such a quick response. Will buy a 3x
Barlow and perhaps a 9 or 15mm eyepiece. I sincerely wish you and the
site continued success.
Very appreciatevly,
Nalin Jain

Subject:	Light Pollution Question
Sent:	Monday, August 4, 2003 08:39:22
From: (Jamie D'Anna)
I live in central New Jersey and own an ETX 90 EC. Will a narrowband nebula
filter help ?


Your site is excellent !
Mike here: It may or may not be useful on the ETX-90. See the reviews on the Accessory Reviews - Filters page.
Subject:	eyepiece choices for ETX-90
Sent:	Saturday, August 2, 2003 20:48:25
From: (Tiffani Brown)
I couldn't help notice Bill Thomas' inquiry about eyepiece choices for
viewing Mars. Here are my recommendations... I routinely use a Teleview
8mm Plossl (156.25x) , due to the excellent optical quality, and the low
glass count. This eyepiece suffers some on eye relief, but the view is
the best possible for a 90mm telescope!  The southern polar cap is very
clear, as is the crimson color, even surface details are well
represented! If you have the means, I have also had great luck with my
7mm Meade Research-Grade Orthoscopic (178.57x) which is still out of the
image break-down zone, yet has better eye relief than the TV-8, yet this
eyepiece is hard to find! I have seen other Orthos (Celestron, circle-t,
etc) on astromart that really perform with the ETX-90, and the
magnification is reasonable for the 90mm aperture.    Chris Brown

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