Last updated: 31 July 2008

This page is for user comments and information of a general nature or items applicable to all ETX, DSX, and DS models. 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:	double stars
Sent:	Wednesday, July 30, 2008 10:53:27
From:	JayJay Clayton (
Trying to understand the relevance of position angle / separation...
seems to me that since one star is rotating around the other, and
assuming that the orbit isn't necessary a perfect circle, that position
angle and separation would only have meaning at the time that it is
actually observed / recorded.  Or it could be that the distances are so
great that the changes are insignificant.  Many thanks for clarifying.
Thanks.  Julie
Mike here: True "double stars" do have one star revolving (not rotating) around the other star (or actually around their common center of gravity). Visual double stars just appear to near each other in the sky. Since true double stars are moving in their orbits you are correct that the current position angle and separation will change over time. How much depends on the orientation and other parameters of the orbits and the stars' distance from the observer.
Subject:	ETX-90 Question--Motor Drive Fault
Sent:	Wednesday, July 30, 2008 10:35:16
From:	Renee Dallimore (
First-GREAT siteI have a 90 and a 125 and your site is where I spend most
of my time finding answers and tips.  I am hoping you can help me out
with my issue.

I've got a 5 year old , optics still work great, ETX-90EC.  I have the
dreaded "motor drive fault".  After calling Meade-it wasn't worth the
cost to send it in, given what I paid for it to being with (I could just
get another 90).  I get that I could, theoretically anyway,  remove the
OTA and remount on another mount.

Question is:  Do you know of such a mount and where I would find the
"how to's" of that?  I've surfed but cant seem to find an answer to
MUCH appreciated!!!
Renee D.
Mike here: There are some tips on the Helpful Information: Telescope Tech Tips page with info on mounting on different style mounts. However, have you tried the various tips mentioned on the ETX Site to address the motor fault?


I must have overlooked them...I'll give them a look-see and thank you !
Mike here: Do a search for "motor fault".
Subject:	ETX-125 meets Vinegar
Sent:	Monday, July 28, 2008 14:56:26
From:	John Landy (
So, my roommate used Vinegar (undiluted) to clean the lens and eyepieces
of my ETX-125. I believe what was used was a soft (I pray) towel and
eventually a t-shirt. In his defense, this is how they did it in
astronomy class back when he was a kid.

I'm presently at a loss.

I've noticed your mention of low quantities of vinegar being less than
choice for lens cleaning. I imagine this has something to do with
applying acidic cleaners directly to the coating. Which was additionally
effected by buffing and scouring, and sitting in its case overnight

Is there anything I can do? Will it damage the coating or just streak,
which I can clean with a different solution? I can take pictures and
send if you need.

Mike here: I'd recommend using distilled water to remove as much of the vinegar that remains (possibly unseen) and a lint-free cloth. Just press a soaked cloth on the surface. Repeat several times. Then I'd recommend using Dr. Clay Sherrod's cleaning solution and technique to thoroughly clean the lens and eyepieces. See the article "Cleaning Optics" on the Helpful Information: Buyer/New User Tips page.


Excellent. I'll do just that.Thank you! :)

Sent:	Monday, July 28, 2008 09:30:08
Sorry for using ALL CAPS.

But thank u thank u  for your advise

Excelletn work
Loucas Ergatoudes

Subject:	re: meade etx 90ec
Sent:	Sunday, July 27, 2008 23:04:11
From:	richard seymour (
The problem -could- be as simple as dirt or grease blocking the "view"
of the optical encoders which detect motor rotation.

Or a disconnected wire inside the telescope so that the Autostar
cannot speak to (or "hear") the motor controller cards.

Or a bad cable between the Autostar and the telescope.

Try reversing the ends of the Autostar-scope cable, and inspect
the sockets to make sure there's nothing in there blocking contact.

The base of the scope can be carefully removed... the screws are
hiding under the three rubber feet.
Remove the AA cells before doing this, and be careful about the
short and fragile wires between the baseplate (with battery box)
and the rest of the scope.
Then peer inside, and verify that all of the plugs are firmly\
You'll also see the white "encoder disk" on the non-geared end
of the motor... check that it's clean, and that the two dark
lumps it's passing between are also clean (one is an infrared
light source, the other is the detector)

There are many articles in Mike's Telescope Tech Tips pages
about opening and accessing the base of the scope

good luck

Subject:	RE: EXT-125PE: Limited travel between the endstops
Sent:	Sunday, July 27, 2008 13:36:35
From:	Gareth Rees (
Picked up the new scope on Thursday and all seems well so far in testing
it on the bench - no wobbles, no motor errors and it goes round nearly
two turns between stops. I have managed to train the drives and go
through a few mock calibrations but I await a clear night  to see if it
all really works.

Best regards and thanks


Subject:	meade etx 90ec
Sent:	Sunday, July 27, 2008 09:54:56
From:	merrideth jones (
i purchased a meade ext90ec from someone on craigslist. kept in really
good shape. started up the autostar. comes up with motor failure
immediately. tells me to change the batteries. i did that. still same
message. no motor sound at all. out of warrenty. can i fix this? are
there parts available for this?
Mike here: Be certain you are not overtightening the axis locks. Also, check that you are connecting the AutoStar to the HBX port on the ETX base. Check the cable connectors and the jacks for dirty or bent pins. Also, the pins should not be too depressed, otherwise they may not make contact. Can you get to any of the AutoStar menu items? If so, try a RESET.


i cannot get any menu items. the message says motor failure. no pins are
bent or dirty. the controller is connected to the port. how can i do a
reset when i cannot access any options on the controller?
Mike here: Do you have a #505 serial cable to connect to the Autostar? If not, you can easily make one using info on the Helpful Information: AutoStar Info page. Then you can follow the steps in the article "AutoStar RESET from Software" on the AutoStar Info page to try a RESET. If your computer has only a USB port you will need a USB-serial adapter. However, not all work reliably with the AutoStar. See the article "AutoStar and USB" on the Helpful Information: AutoStar Info page.


i do not know where to get the items listed in the article.

do you really think that this reset will solve the problem. the auto
star states the minute the power is turned on that it has detected a
motor unit failure? i cannot get the controller to enter safe mode or
anything else.
Mike here: Probably not but it was cheaper than the alternative. Getting replacement parts would require that you determine WHAT parts have failed. And to do that would require a disassembly of the mount. It could be a broken wire, a dead motor, or other causes. And then once you ID the part you would have to try to find a replacement. Some replacement parts are available from Telescope Warehouse (link on the Astronomy Links page). By the way, do NOT put the AutoStar info Safe Load mode; that would require you to reload the ROM and that would require the #505 serial cable, etc. You could try reloading the ROM, which would help if the software was corrupt. But I really suspect some sort of hardware problem.
Subject:	Celestron Power Tank Adapter
Sent:	Saturday, July 26, 2008 10:43:28
From:	kevin wonders (
I just received a power tank but it has the wrong size for my ETX123PE.
Any ideas on a plug that could be used instead?
Kevin Wonders
Mike here: See the article "ETX AC Adapter Plug Info" on the Helpful Information: Telescope Tech Tips page.
Subject:	ZOOM ETX 125
Sent:	Saturday, July 26, 2008 04:43:04
Mike here: You can use other eyepieces and/or a Barlow Lens. The ETX should have come with a 26mm eyepiece. Shorter focal length eyepieces will yield higher magnification. Using a 2X or 3X Barlow Lens ("shorty-style" only on the ETX) will double or triple the magnification of a given eyepiece. For more on eyepieces and Barlow Lenses see the Accessory Reviews: Eyepieces page as well as the Helpful Information: Buyer/New User Tips page. If you do not know how to calculate magnification see the FAQ page.
Sent:	Saturday, July 26, 2008 03:56:27



Mike here: Please read the Email Etiquette item on the ETX Site Home Page; it discusses emails with ALL CAPS. Thanks for understanding. You can probably take the screw to a local hardware store and they could match it.
Subject:	AC Adaptors
Sent:	Friday, July 25, 2008 14:55:14
From:	Niall J. Saunders (
Scott, you are really frightening me - what you are doing (or trying to
do) really suggests that you have little or no grasp of electronics, and
stand a very high chance of causing significant damage to you and your

From what I can see, you have a multimeter (which you are not confident
in using) and are trying to measure (a) the voltage of your triple PSU
setup and (b) the current of the same setup.

Whilst, in theory, you CAN manage to achieve (a) using your multimeter
(by connecting the meter probes to the + and - leads from your combined
PSU setup) you absolutely CANNOT do the same for (b)

You have been VERY lucky so far. By rights you should have blown your
multimeter protection fuse - the fact that you have not suggests that
the meter is incredibly cheapo, and therefore provides you with
absolutely NO protection should you try doing what you did. Had you done
the same test on a car battery, or (worse) your domestic mains socket -
you could have suffered quite horrific injuries as your multimeter

You should NEVER measure 'short circuit' currents unless you REALLY know
what you are doing.

And that is what you are seeing - the current that all three supplies
could produce is you just joined to + and - wires together - something
you would normally try very hard to avoid, but which you have achieved
just by using your multimeter. Leave things connected like that for long
enough, and you could have had your own 4th July fireworks !!

And you should NEVER, EVER join multiple power sources together as you
did - unless you have excellent house and life insurance. You really
MUST HAVE a thorough knowledge of electronics to get three separate
power supplies to 'current share' - and usually supplies that will do
this safely cost hundreds, if not thousands, of dollars each. Trust me -
I design and build them, and the solutions are NOT trivial or

Finally, I am still struggling to understand WHY you feel the need to
join more than one AC to DC converter together. If you have a 12V 3A DC
supply, then you have FAR MORE power available than you will EVER, EVER,
EVER, EVER need to drive any Meade ETX, LX90 or LXD55/75 scope (ever).
Even my FULLY LOADED LX90 (with all sorts of piggy-backed nonsense and
extra weights, cameras etc.) still only draws JUST OVER 1 Amp - three
times less than a single one of your supplies.

And as for the voltage - if the manufacturer declares the output to be
'12V 3A' then they really mean a MINIMUM of 12V at a MAXIMUM current of
3A. Yes, it could well be 'significantly higher' than 12V when at ZERO
Amps (no load, for example when you are JUST using a meter to measure
the voltage) - but THAT measurement is really quite pointless.

UNLESS you have purchased a FULLY REGULATED power supply - which is what
you SHOULD be looking for. In other words a power supply that produces
its specified output voltage (e.g. 12V) at WHATEVER current you choose
to draw - all the way from 0A (no load) up to the maximum (e.g.) 3A at
full load. And this power supply should also 'fold-back' its output
voltage (perhaps all the way to ZERO VOLTS) as you draw current beyond
the rated maximum, all the way to the scenario where you just join the
output leads together (as you effectively did when you tried to measure
the 'current' of your 'time-bomb' earlier).

And that is why you perhaps WERE able to read the 'current' as being
18Amps - it probably 'was' 18A, but the Output voltage under those
conditions was probably a very small fraction of a volt - almost no
volts at all - and hence no power.

So, please take care. And please be even MORE careful if you are going
to use a power supply to charge a battery which is then going to be used
to run your telescope. Get that combination wrong and a visit to
hospital will be a luxury - more often you will be heading to the
morgue, or will have at least caused so much damage to your eyes that a
telescope will be a somewhat pointless investment. Just be aware that
batteries only exist for ONE purpose - and that is to kill, injure or
maim human beings (and, for that, they have a huge arsenal of weaponry
at their disposal, including toxic chemicals, corrosive chemicals,
explosive gasses, huge energy release, etc., etc.)

Sorry to 'go on and on' - this is NOT meant to be a 'personal rebuke' -
it is to help those who are NOT sure about what they are doing from
causing really nasty problems.

Hope this helps.

Niall Saunders
Clinterty Observatories
Aberdeen, SCOTLAND

Subject:	New ETX-125PE
Sent:	Thursday, July 24, 2008 13:28:30
From:	Steve Hollar (
Mike, just wanted to let you know I ordered one of the specially priced
ETX-125PE's yesterday. I'm quite anxious to get my hands on it.

Also, it was great seeing you at the expo Saturday. I'm still bummed,
though, that I missed your talk.

Steve Hollar 

Subject:	AC Adapters
Sent:	Tuesday, July 22, 2008 13:02:39
From:	Scott (
I agree, AC adapters output MORE DC current and voltage then stated on
the label.  I connected (x3) AC adapters rated at 12V 3A  in parallel. 
Sniped the DC output ends off and  soldered the 3 positive wires
together to a wire and soldered the 3 negative wires together.  The
results showing on the multimeter were around 19.50 Amps and just 12.50
Volts!!!!!!!!!  I guess I can see the volts because they were connected
in parallel, but the amps, that high????????

Specifically I am getting around 6.4 Amps per AC adapter rated at only 3
amps.  I wonder if any of these adapters has a current limiter?

Subject:	RE: MySky Problems
Sent:	Tuesday, July 22, 2008 01:46:24
From:	John & Andrea Beaderstadt (
Called Customer Service again yesterday, and they are now saying upfront
that the download is a corrupt file.  Also, there was something about
how the download utility that loads from the disc may be responsible "on
some computers."  Not sure what that means.  I also showed them that the
web site gives no indication what version is going to be downloaded.

Luckily, the problem seems to be confined to what's on the SD card, and
the "solution" appears to be to have two cards available.  Never
reprogram the second card until you're sure that the programming on the
first card is OK.

Subject:	Fantastic...
Sent:	Monday, July 21, 2008 23:36:55
From:	Dave Harris (
Just a brief thanks to you for assisting in my usage of the ETX125 - a
most remarkable beast indeed and actually managed to do some proper
observing for the first time since ownership last Saturday despite being
a full moon!

Very impressed and your site is a mine of info - even got it bookmarked
on my iTouch...!

Glad you and your colleague managed to solve my, er, user problem with
the deep sky Goto as well!

So, next on the list is to to some astrophotography - I got the Toucam -
just need a USB extension lead and I am away!

Most cordially yours, as ever!


Subject:	questions about ETX-90EC
Sent:	Monday, July 21, 2008 19:51:05
From:	matt (
I recently got this from my uncle during the 4th of July. I have a
couple of questions.

1. Can you use a telrad type viewfinder. Or should I stick to the
viewfinder and get the 90 degree one.

2nd I would love to use the 505 cable but I don't have a serial port on
my dell inspiron 9100, so I am looking at a serial to usb. I cant tell
if the two would match. One being a female  and the usb part being a

3rd any suggestion for anything to do with the scope itself would be
great. Like example get a DC instead of batteries. How about a dew
shield? Just suggestion like these would be neat. Thank you mike and
Mike here: Telrad: yes (see the Accessory Reviews: Finderscopes page. USB-serial: see the article "AutoStar and USB" on the Helpful Information: AutoStar Info page. For other tips there are many pages on the ETX Site: external power reviews on the Accessory Reviews: Miscellaneous page, more on the Helpful Information: Telescope Tech Tips page; dewshields and more on the Telescope Tech Tips page.
Subject:	Re: broken arm on etx125 gear drive box
Sent:	Monday, July 21, 2008 16:52:10
From:	david eigenberg (
thanks for the response and the location on the web sight.. helped me
out considerably... appreciate it
thanks, dave

Subject:	EXT-125PE: Limited travel between the endstops
Sent:	Sunday, July 20, 2008 01:19:23
From:	Gareth Rees (
I live in Bristol in the UK and have just purchased my first ETX-125PE
(second if you include the first that wobbled and gave motor errors).  I
align it as described in the manual by rotating anti-clockwise it to the
end-stop and then engaging the clamp. When the alignment starts it then
rotates clockwise to find level and north and often (depending on where
north is) it hits the other end-stop and the motors stall.  When I
looked at it on my bench it only has ~300degrees of free motion between
the end-stops. Is this normal or is there something that I'm missing?
Best regards and thanks in advance
Mike here: The ETX should rotate horizontally almost twice around between hardstops. So something is interfering with that movement. It could be a wire so don't force the movement or you could cut the wire. Since the telescope is new you should contact the dealer for an exchange. You could open the base to check for a wire but use caution messing around inside the base.


Many thanks

I have returned it today and (hopefully) a new scope should be with them

Best regards


Subject:	MySky Problems
Sent:	Saturday, July 19, 2008 12:00:19
From:	John & Andrea Beaderstadt (
Got my floor-model MySky just fine, but it hardly worked at all.  Tried
an upgrade off the Meade web site and it pretty much hosed the MySky
completely.  The thing would lock after manually entering my location
and, after just turning it on, I'd get a message to the effect that the
calibration had failed.  Called Meade, and they had me exchange it for a
brand-new one.  OK, so far, and I made out like a bandit (remember, I
paid a total of $225 for it , off Amazon).

The new one arrived and worked just fine, right out of the box.  It's
been completely overcast, so I just spent my time playing with it.  Then
I decide to ugrade the firmware again.  Guess what?  It completely hosed
the MySky, again.  Called customer support, and a different guy wanted
me to send it in again.  I argue with him a little bit, and he finally
buys into the idea that it was the download that was responsible.  Not
only that, but then he seems to recall that other users have been
lodging the same complaint.  It seems, among other things, that the web
site is downloading v1.2g when it should be downloading 1.2nt (I think).

The really annoying thing is that there doesn't seem to be any way to
tell ahead of time whether you actually need to do the upgrade; the
MySky screen will tell you what version you have, but there's absolutely
nothing about the upgrade process that will tell you what will be
downloaded, or that will give you the option of changing your mind. 
About the only thing I can think of is that you should have two SD
cards, and never upgrade the 2nd until you know that the 1st one is OK.
So, the last I looked, Meade had not fixed the upgrade problem. 
Mike here: At Saturday's SCAE 2008 at OPT, Meade announced the "mySKY plus". A completely new version of the software will be available on their web site during the first week of August. I received a card with the new software at SCAE; I hope to test it as soon as the monsoons here allow. Two changes that I know of: GPS is disabled and there is a lot of new Audio/Video material with a new narrator.


They disabled GPS?  I thought that was a major selling point.  Not that
it matters; I don't know why it assigns you to the nearest town, rather
than just using your coordinates.

Any idea on when they'll release the new software, or is it "real soon
now"? I just tried an upgrade again and I'm still getting v1.2g
Mike here: First week of August on their web site. As to GPS elimination, they said to improve the user experience (too long a delay acquiring the GPS location) as well as just too many issues with GPS.
Subject:	Replace finder scope ETX-90
Sent:	Friday, July 18, 2008 15:42:44
From:	Jim Drzewiecki (
I have an ETX-90 and I want to replace the Meade right angle finder
scope. I removed the mounting bracket and I'll have to drill two small
holes through the telescope's rear cell to fasten a mounting shoe

My question is will this damage the telescope in any way. Has anyone in
this group done this?

Jim Drzewiecki
Mike here: There are alternate ways to attach finderscopes, including using the existing holes (you might need to make an adapter). However, if you want to drill holes, you need to avoid letting any debris enter the OTA and you need to avoid drilling over the mirror or other internal components.
Subject:	broken arm on etx125 gear drive box
Sent:	Friday, July 18, 2008 10:59:39
From:	david eigenberg (
i recieved  your info from woodland hills camera as to you were the guy
who knew alot. my etx 125 has a broken part in the undercarriage of the
telescope, i believe it is the azimuth drive and the broken part is the
arm that holds the gears... its a crappy blue plastic housing that also
that holds the drive motor in place and i'm not sure how to describe it
to meade to get the replacement part. if you have a moment to advise i
would be very grateful.. i imagine this part has had a few problems
cause it doesnt appear to be well designed... the rest is wonderful...
but alas i'm stuck and cant rotate the telescope.
thank you .. uncrankable in burbank,dave eigenberg
Mike here: You might see the articles "Gearbox Replacement" and "Fix for Worm Gear" on the Helpful Information: Telescope Tech Tips page. But I suspect you will need to contact Meade.
Subject:	Re: Meade 125 Focus
Sent:	Tuesday, July 15, 2008 23:02:50
From:	P. Clay Sherrod (
Very the moon is a very difficult object when full, and
provides very little detail; at this time you should have been
attempting to focus on the EAST edge, where there is still some shadow
in the craters.  Try focusing on a very bright star nearly overhead and
see if you can get it to focus....if not, I suspect that your main
mirror has actually come loose on the sliding cell and needs to be
But try the star and give it a second chance.
Best of luck.
Dr. Clay
Arkansas Sky Observatories
Observatory Hill Drive, Petit Jean Mt.
MPC/cbat Obs. H41 / Petit Jean Mountain
MPC/cbat Obs. H45 / Petit Jean Mountain South
MPC/cbat Obs. H43 / Conway
MPC/cbat Obs. H44 / Cascade Mountain

----- Original Message -----
From: dean engel (
I have a perplexing problem, and I am hoping you can help.

I have a Meade 125, and I was looking at the moon the other night and
then I went back to it, and it was now completely blurry.  blurry to the
point that it really looked like a white diffuser on a light bulb, no
features/no nothing.  It was, not dropped bumped or the focus was not
even moved.

I thought the focus, and the answer from this site sounded perfect

However, mine was in fine shape.

I can take off the eyepiece and see through it fine (not sure If I could
before hand, it is new to me, never tried it)  I thought this would help
me know if there was a problem with the mirrors, but it looked fine.  I
took off the camera lens cap and I could see through it as well...

Would you have any idea,  I am sure it is an ignorant stupid question.

I appreciate you help.
Mike here: I wonder if the optical surfaces had become coated with dew.


Excellent point....

Dr. Clay


I will try the star overhead.  When I did this (10 days ago) we were
about 1/4 crescent, it was a great show until this occured.  It was
awsome to see the rings of saturn.  Kids had a blast, the big reason i
picked it up.

Mike, dew is always a possiblitily but I think I can elmininate it in
this situation, since I have tried it again since then.

I don't have much experience in dew, but I was on a houseboat in Lake
Powell UT, where humidity is only a wishful dream, and it was in the
90's, since the houseboat was not Air Conditioned, All equipement was
about the same temperature. However the sky is brilliant since there is
not really a town for a few hundred miles.

I will take a look into the overhad star and see what happens.  When you
say the main mirror has come loose, is that the main reflector in the
back,  when I took it out to check the focus tab, it looked stable, and
well attached, anything i should look for?

Where/how can you get these repaired if I need something like this done?

THank you very much for your thoughts.
Mike here: Besides the corrector lens at the front, there is a secondary mirror on the back (inside) side of the corrector lens. There is also the flip mirror at the rear of the telescope but if that had moved then you would see a lot of image shift when focusing. As to repairing, Meade or Dr. Clay's Supercharge service.
Subject:	GPS units from;   Which best for;ETX125EC/AT with;497 Autostar?
Sent:	Tuesday, July 15, 2008 07:28:50
From:	joe parr (
I would like to know which of the units from abovementioned Company
would you recomend as the ;"best &easiest ", to use with my scope?

Also what is included in product,i.e.;gps unit,right cable for my
scope,software"Key"?They ae not clear to me as to whether these items
must be ordered separetly or included in pkg. form?

Thank You for your website. 

Clear Skies. 
Joseph Parr
Mike here: There are some GPS articles on the Helpful Information: AutoStar Info page. My experience is limited to the one I review (StarGPS-LX).
Subject:	Reg:Eye pieces
Sent:	Tuesday, July 15, 2008 03:33:21
From:	ramesh (
Recently I had bought the telescope MEADE ETX-125PE. As I am a beginner,
I am bit confused to select the best eye pieces for observing the
objects such as Galaxies, Galaxy clusters, Nebulas, Globular clusters,
Planetary Nebulae, Planetary and Lunar details. Even though the AUTOSTAR
has a calculation facility for selecting eye pieces I am willing to get
advice from experts like you so I kindly request you to help me or
advice me to select the best eye pieces to observe the above said
objects. Anticipating your reply.
Mike here: There are several articles on eyepieces on the Helpful Information: Buyer/Mew User Tips page and on the Helpful Information: Observational Guides/References page. Check those for some guidance.


Thanks lot for your mail.



Subject:	ETX-125EC Question
Sent:	Sunday, July 13, 2008 16:34:23
From:	Austin Ford (
I have just purchased a ETX-125EC. great scope. I have a problem though
with the image jumping left and right when I use the focus knob. I'm
assuming it's the internal mirror moving slightly when I focus (I am
very new to this so freely admit I could be wrong). It dosen't stop me
from using the scope but does becomes slightly annoying when you're into
high magnification and the image moves. Is there anything I can do to
sort this problem out and has anyone else ever had this problem with the
Mike here: Since you say it is an ETX-125EC I assume it is a used one. There was a problem with some early ETX-125EC telescopes with excessive image shift. That was back in 1999 and Meade repaired them free of charge (back then). There could be other reasons for excessive image shift including the optics being out of collimation. If you want to try a fix yourself there are a couple of articles on "image shift" as well as articles on collimation (difficult) on the Helpful Information: Telescope Tech Tips page.


Phew that was a bit nerve racking! I found a article on image shift on
your website and followed the procedure to try and correct it. Once I
had the primary mirror out and in my hand! I noticed that the bottom
part of the central column (nearest the mirror) was not screwed in tight
enough. Once I had tightened it and then managed to put the scope back
together it eliminated nearly all of the image shift. There is still a
fraction of image shift (which I am not happy with, but can live with)
although it is certainly a lot better than before. Cheers for your help.
Much appreciated.

I have another question though... If I had to clean the primary mirror
(for some hypothectical reason) what is the best way to go about doing
it? I have read that the coatings on all the optics need periodic
renewal - Is it best to send the scope off to be seviced somewhere?
Mike here: Cleaning the primary mirror is possible. BUT you don't want to touch the surface as there is NO coating or other protection. You can use a blub-style air blower (NOT a can of compressed air) to blow dust off the surface. I have heard of some telescope owners "bathing" their mirrors in a very diluted soap solution and then letting it air dry. But this is difficult and chancey as you don't want to end up with any streaks on the mirror. Periodic recoating (aluminizing) usually only needs to be done every few decades. For recoating of the optics (standard or UHTC) it would have to go back to Meade.
Subject:	ETX-125 problems
Sent:	Friday, July 11, 2008 01:02:05
I recently bought a Meade ETX-125AT telescope. The first time I used it,
I tried to perform the easy align following exactly the instruction
manual's procedure. When the telescope began slewing to the first
alignment star, it stopped and the Autostar gave a motor drive fault. I
also noted a burning smell. Since then the telescope refused to move
left and down. I performed a reset and calibrate motors. Nothing
happened. The telescope does not move left, does not move down either.
Note that I worked with the Condor AC adapter provided by Meade.

The official representative here in Greece offered to send me a
replacement telescope. First night out, I managed to complete the easy
align procedure and I pressed Goto Jupiter. The telescope found and
tracked the planet for a couple of minutes and then Motor drive fault
and a slight burning smell. Then the telescope refused to move down.
Every time I turn it on, the optical tube moves rapidly downwards.

I used the same Condor AC adapter again. Please note that I performed
reset, calibrate motors and train drive before I started the easy align
procedure. I am sure that I am setting and using the scope properly, I
just follow the instruction manual. I thought that something is wrong
with the AC adapter. I measured the output voltage at 16.5 Volts!
Shouldn' t it be near 12 V?

I sent the scope and the AC adapter back. The representative tells me
that it's the first time such a problem appears and that probably I do
not use the scope properly I am absolutely sure it's not my fault. What
could be the possible reason for all these? Thank you very much and
congratulations for your site.
Arta, Greece.
P.S. 1: Having read all the complaints from other frustrated Meade ETX
users, I believe that Meade Instruments Inc. should consider eliminating
all those quality issues, even if the scope's price goes up. It's been
over a month now and I haven't been able to solve this issue.

P.S. 2: The telescope is made in China.
Mike here: I seem to recall one other report of a defective Meade AC Adapter.
Subject:	primary mirror not centre in Etx 125?
Sent:	Sunday, July 6, 2008 09:32:14
From:	Melt Down (
I'm confronted with a strange misalignment in my Etx 125 (old model).
Secondary mirror seems aligned perfectly with the primary. Star test
also seems ok. But the whole is rather badly misaligned with the primary
baffle tube.

Looking through the back of the telescope using a film canister shows it
clearly. Also using the top position eyepiece entry shows it. Sending it
back to Meade isn't really an option here in Holland. I'm very handy
myself so i won't mind doing things myself but i first need to know how
this is possible.

Any suggestions?

Michael Siethoff
The Netherlands
Mike here: If the optics are collimated then I wouldn't worry about it. If the star test shows a good collimation then any light loss from a misaligned baffle may be mininal. But if you want to risk making things worse you can open on the tube, reposition the primary mirror mount (maybe), reposition the baffle (maybe), reposition the secondary mirror (maybe), reassemble everything, and then recollimate the optics (maybe). At the end of all this you may have a working telescope (or you may not).


Thanks for replying, much appreciated.
I'm no stranger with collimating optics.
Have done that many times.
My question was asked the wrong way i guess, happens when not native
with English.
I guess the baffle seat must have shifted somehow.
The OTA never has fallen or damaged in any way so the cause remains a
mystery until i open the OTA.
Thanks for helping.

If you're interested i can send you some photo's how i modified the old
Etx with needle ball bearing in the base and ball bearing in both arms.

Michael Siethoff
Mike here: If the baffle has shifted, see the articles "ETX-90RA Secondary Baffle Fix" and "Re-attaching the Baffle" on the Helpful Information: Telescope Tech Tips page. As to your modification, sounds interesting and would make a good Tech Tip article.


Sorry i should have said the primary baffle.
A little more difficult to do ;)
I will send the modification shortly.


Subject:	power for ETX70
Sent:	Saturday, July 5, 2008 00:26:43
From:	Henrik van Holthoon (
Your are using rechargeable batteries as you wrote to Mike. This is not
a good idea rechargeable batteries have a 1.2 voltage compared to 1.5 to
normal batteries, as you need 6 batteries for the ETX70 then 6 x 1.2 =
7.2VDC and 6 x 1.5 VDC = 9 VDC. Difference is  1.8 V.

I advice you to use normal batteries 7.2 volts is really on the low

Regards Henrik

Subject:	ETX70AT alignment problem - time question
Sent:	Tuesday, July 1, 2008 01:46:09
From: (
I have recently bought the ETX70 AT and am having trouble getting the 2
star alignment process to work. I have had a look at a lot of your
excellent feedback to the many others who seem to have alignment
problems and was wondering whether the time setting is my problem as I
think I have the correct 'home' position. I live in Spain almost exactly
on the GMT longitude, but my local time is 2 hrs ahead of GMT. I
wondered whether I should be setting the time to GMT or my local time.
What is the software expecting?

I have actually tried both in my attempts to get the alignment working
and am still having problems. You mention a few times in other feedback
about batteries, but I haven't found the original information about why
rechargeable batteries should not be used. Could you please explain
that. I use rechargeables but make sure they are fully charged before
starting observing.
Thanks for your help.
Mike here: I think you are looking for the article "Rechargeable Batteries" on the Helpful Information: Telescope Tech Tips page. One thing to keep in mind is that after recharging (and perhaps as the batteries discharge with use) you need to do the CALIBRATE MOTOR step. Also, have you done a TRAIN DRIVES? As to the time issue, the AutoStar will expect to locate the alignment stars (and other objects) based upon their position in the sky for your local time and site location. However, if your local time zone is out of whack then you should adjust it. But since you indicate that you have tried both, the CALIBRATE MOTOR and TRAIN DRIVES may solve the problem for one of the time settings. One thing that may help is to determine how far off the first alignment star is in RIght Ascension. Remember that 15 degrees equals one hour.


Thank you very much for getting back to me so quickly. I followed your
advice and managed to get the alignment to work. I thought that I would
let you know that the time I needed to put in was Universal time without
any adjustment for summer time (not the local time).

I have been setting the home position to magnetic north, but have seen
some discussion on your forums that it I should be using true north. Is
there an article or note on the difference? The manual actually advises
using a compass for setting the home position.

Thanks and regards
Mike here: The difference in Magnetic vs True North can vary from 0 degrees to up to about 20 degrees, depending on your location. There are a couple of web sites (see the Astronomy Links page) that can determine your Magnetic Variation (also called Magnetic Declination). However, even if you use a compass, once you center the proper alignment stars, any error due to the Magnetic Variation will be removed.

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