Last updated: 31 January 2005
Welcome to the Autostar feedback page. This page is intended to provide user comments on using the Meade Autostar, cables, and the Autostar updater software. See the Autostar Info page for information from Meade and other users on the Autostar, cables, and software. Send your comments and tips to Remember, tips described on this site may invalidate the warranties on your ETX and accessories. Neither the submitter nor myself are responsible for any damage caused by using any contributed tips.

Subject:	My Autostar won't talk to my pc
Sent:	Sunday, January 30, 2005 11:55:56
From:	Dave Hoeppner (
I ran across your article, dated July 25, 2001, about trouble shooting
the com port/checking the cable (How to test communication to an
Autostar). I have windows xp on my computer.

I tried everything in your article and could not get any of the com
ports to work using Hyperterminal. The cable test worked as you
described, but still my Autostar will not communicate with my pc. I
recently talked to the techs at Meade about this problem and sent my
Autostar back to them to have it checked out. When it came back, it
still would not communicate with the pc. I have loaded and unloaded the
autostar suite program a half dozen time or more, to no avail (also went
the Meade site and have the latest update for Autostar Suite). I have
also went to the windows site and down loaded the most current .net and
directx (9) on my pc. since I have an LPI camera (which is working
fine), I'm not sure if this might have created a problem.

Well I'm dangling at ropes end and hoping you may have another solution
up your sleeve that may solve my problem and get my Autostar talking to
my pc.
Dave Hoeppner
Mike here: The most common source of a problem is a port conflict. Typically that comes from fax software, or any software that is keeping the serial port open so that the Autostar software can not use it.
Subject:	Very strange
Sent:	Saturday, January 29, 2005 12:17:35
From:	Andrew Sprott (
Whilst debugging my NTC code I came across two problems.

1: I have to convert between sexigesimal numbers to decimal which causes
a problem.

If I send a decimal Azimuth co-ordinate say 4.333333333 etc, I have to
convert it to sexigesmal ie., degrees, minutes and seconds. So I would
return the integer as the decimal part, Multiply the fraction by 60 and
return the integer as minutes etc.

The problem is the fraction part, which is .3333333 recurring, is
multiplied by 60 to make it magically appear as 20 which is fine. But
when I want to convert this to a integer variable, ie., minutes it
returns 19. IOW,



minutes is assigned 19, which is strange.

But even stranger is the Autostar...

It returns the scope position as...

00108# azimuth
+3228# altitude

sending the following sequence after the Delphi conversion should move
the scope a tiny part anti-clockwise...


but a query returns the scopes position as...


Shurley shome mishtake as the scope did shurley move 16 degrees

I hope this makes sense.

Andrew Sprott
And from our resident Autostar expert:
From:	Richard Seymour (
Not strange at all.  I don't know what your "NTC code" is, but i'll assume
it's a control program for a telescope (497 Autostar or LX200gps AutostarII?)

4.3333 * 60 is 259.999999999
Most "friendly" output-for-people procedures "round" the number to
the precision you specify.  So it you asked the above to *display*
as a "real" number, but with zero digits beyond the decimal point, 
it would -show- 260.   
But if you ask it to *calculate* with it, it's still 259.9999999
"Trunc(m)" does -exactly- what you ask it to do: truncates 19.9999 to 19.
If you really want "rounding", look for a "NINT" (nearest integer)
function, or make it -clear- by simply adding 0.5 before Trunc'ing.
(the "trunc" function is probably redundantly superfluous... all
programming languages i know of perform an implicit truncation when
they convert from real to integer across an assignment statement.)

The above discussion does not go into the -second- detail that 
computers are binary beasts... numbers are carried as powers-of-two,
so 0.33333  cannot be -exactly- represented.  It will suffer a little
bit of truncation of its own, simply due to the way IEEE-754 numeric
representation works.  It's carried in your PC as (hex)3EAAAAAA,
which is -really- 0.33333331 when expanded.   Add x00000001 to it
(x3EAAAAAB) and it becomes 0.33333334.      See:

"Normal precision" real numbers are only good for slightly less
than 7 significant digits.  So 259.99999999  only truly has four 9's 
(since three digits are lost to the "259").

But even stranger is the Autostar...

I'll address -that- in my next note (after i've played with it).
(But i'd prefer more context: what version Autostar firmware,
what -other- commands are you sending, and have you run an alignment?
BIG question: are you in Polar or Alt/Az mode?)

have fun
And more:
If you read the Meade serial command document at
you'll see that the :Sz  command is (theoretically) only supported
 in the LX200gps and LX 16".  
But they do say that :MA# should work, too.

What is -happening- is that the number you are supplying is being
semi-interpreted as an RA setting ( :Sr ), which causes an x15 scaling.
(one RA hour is fifteen degrees)

I just told my v33Ef ETX90 to :Sz10*00:00#:MA#
And it slewed to Az 150*00:00#     
Fifteen times ten is 150.

Therefore, with the current firmware, you will need to send Azimuth
angles scaled down by a factor of 15.

I'll be sending a note to Meade about this...

have fun
And more info:
Double hmmm....

I can see how to patch it, so that it operates properly.

The following two lines, added to my 33Ef patch kit,
or simply processed as a "standalone" patch, would fix the :Sz command.

R 46ECE  04  3c
R 48E13  FF  C7

have fun

Subject:	Re: My etx 105 overshoots when using arrow keys
Sent:	Friday, January 28, 2005 03:56:20
From: (
Ok I'll try that. Thanks for your time and thanks for providing such a
great website.

Subject:	Re: Slewing problems
Sent:	Friday, January 28, 2005 03:36:40
From:	Andrew Sprott (
Mike said:
> Usually the slew to 90 degrees means CHANGE THE BATTERIES.

Err, it is running off the mains.

Mike here: Did you do a CALIBRATE MOTORS and TRAIN DRIVES? What power source? Voltage?


Nope, BTW I've flashed the firmware from 30ee to 32ef, but havent tried
it yet.

Weell, 12v off a battery that is being charged.

Mike here: Any time you do an Autostar Update you should at least TRAIN DRIVES. What's the amperage? You will need about 1.5A to avoid problems.
Subject:	ETX90EC and Autostar
Sent:	Thursday, January 27, 2005 17:26:12
From: (
I was one of the unfortunate customers that bought one of your ETX 90EC
telescopes back when the Autostar was not Included.  The scope is GREAT
but now having to PAY $150.00 for the Autostar is a real killer!!!!

I was wondering which Autostar model number will work with my telescope?
#495,  #497 ?????????  Thanks 

Paul Quenneville
Mike here: See the FAQ page on the ETX Site.
Subject:	Slewing problems
Sent:	Thursday, January 27, 2005 14:17:45
From:	Andrew Sprott (
I've decided to take NTC off my server for the time being due to
problems I'm having with the Slewing function. Because of network
congestion, it is possible that NTC will go into an endless loop. I'm
trashing the code I had to write to overcome complications with the
mouse events. The new code works better and is more suited to latency
issues with the Internet.

Rather than slew the scope, I'm using the GOTO feature to move the scope
by video capture frames. I'm also adding the option to move the scope in
steps. This way A: I can check if the scope will go below the horizon
and B: using GOTO is much faster than slewing, and also gives more
control when the network connection isn't exactly responsive.

My ETX 90 is playing up when I try to align the scope, the barrel just
goes up to 90 degrees and I have to switch it off. I'm going to try
flashing the latest firmware.

A question: how can my software know when the Autostar has finished the
GOTO. I try to set a timer and check the scopes position until it
matches the co-ordinates I told it to go to, but the problem is the
tracking changes the position so it may never get to the destination.

BTW, people in the UK might be interested in our March 4th Star Camp
here at Trefach...

Andrew Sprott
Mike here: Usually the slew to 90 degrees means CHANGE THE BATTERIES. As to detecting when the GOTO is complete, I'll leave that to Dick Seymour.


From:	Richard Seymour (
Send the serial command     :D#

The  Autostar will respond with  one or two characters:
 a (hex) xFF    followed by a "#"  if it's still moving,
and only the "#" if the motion has completed
("creep after beep" can happen, if you're not "tuned").

This is documented in Meade's serial command document,
the only difference being that the Autostars only return -one- 
distance bar, irrespective of how much they've still got to go.

have fun

Subject:	My etx 105 overshoots when using arrow keys
Sent:	Wednesday, January 26, 2005 11:34:22
From: (
Hi, I've recently purchased a Meade etx 105 and really like it, apart
from the fact that when I use the arrow keys to move the scope, it tends
to over shoot moments after i release the key. Also, there is a slight
time delay from when I presas the key to when it actually starts moving
the scope. Any help would be great. Thanks, Joe.
Mike here: Have you performed the CALIBRATE MOTORS and TRAIN DRIVES steps as discussed in the manual?


Yes I've done that but it doesn't seem to make a difference. Perhaps
I'll try again and see if it helps. In your oppinion are problems with
the autostar and arrow keys usually user related and not faults in the
way its made?
Mike here: Most times it is documentation that is not clear and/or not reading the documentation at all that is the culprit. Sometimes, there can be bad hardware or corrupted software. Doing a RESET, checking the telescope model and mounting mode, CALIBRATION, and TRAIN DRIVES will usually resolve most problems. However, if not, there are many tips on the Helpful Information: Telescope Tech Tips and Autostar Info pages that people have used.
Subject:	Polar alignment question for my ETX
Sent:	Tuesday, January 25, 2005 13:06:33
From:	Jim Holland (
When I set the autostar setup>telescope>mount>polar mode. Should the RA
motor run all the time on my ETX as soon as I set the mode?

Also do you still need to do alignments (such as two star) in polar

I ordered your book, can't wait to get my hands on it


Jim Holland
Mike here: Thanks for ordering the book. Yes, you still need to do the alignments so that the Autostar knows WHERE to locate objects if you plan to do GOTOs. But if you want to skip that, you can just set the tracking mode to Astronomical and then the RA motor will start running right away.
Subject:	re: Removing old data from auto star
Sent:	Monday, January 24, 2005 20:37:40
From:	Richard Seymour (
This question has one "guaranteed correct" answer,
and a bunch of "qualified maybe" answers, which vary with model of
Autostar and version of firmware.

The "guaranteed correct" answer is: use Meade's Autostar Updater (ASU)
utility to work with the User Object libraries.
It can sort by date, alphabetically, etc., and will show you a
running total of how much space you have available.

Full click-by-click instructions at:

For a 494 Autostar, that is the -only- way to truly free up space.
If you "delete" an object from the 494's Autostar display, it's
not -really- releasing the space, it's merely making -that- object
inaccessible via the menu system.  Only the ASU can "garbage collect"
a 494 Autostar.

With the 497 Autostar, the answer's a little different:

If you have firmware older (lower number) than 3.0b, you -can-
delete objects with the keypad, and it -will- release the space.

If you have firmware -newer- than 3.0b (inclusive), then it becomes
like the 494, and no longer has self garbage-collection capabilities.
(Meade took over the space required to add the Autostar Suite functions).
Only the ASU can truly "erase" the deleted objects.

Satellite data which is over a month old is "obsolete"
 (you can sort by the Epoch Date)
Asteroid data is good for years, Comet data is good for years,
but you may want to add new ones as they're found, and delete the
ones which are far too dim to be seen for the next year or so.

have fun

Subject:	Meade DS 2114 ASTA
Sent:	Monday, January 24, 2005 18:41:52
From:	Daryl G. (
I recently purchased the above referenced telescope,and am brand new to
the hobby. I have the following questions. 1) Does the time have to be
re set each time the unit is turned on, even though it has been
initialized? 2) Does the telescope have to be aligned each time it is
turned on? 3) When setting "Alt/Az home position" and after
repositioning the telescope, then pressing ENTER (on the hand box); is
it normal for the unit to go into a slew for star alignment? 4) At the
end of the slewing maneuver, I notice the movement and the noise from
the motor slows way down, and finally there appears to be no movement
but a low pitch noise continues from the motor like its is up against a
stop and straining, is this normal???
                                              Thanks for your help,
                                                      Daryl Schreiner
Mike here: All that you ask about is normal. The Autostar asks for the date and time when powered on. There is no "internal clock" that keeps running when there is no power applied. And since there is no internal clock, the alignment steps are necessary each time as well. HOWEVER there are sleep and park modes. Sleep is a low-power mode which stops the tracking motors but remembers the time and alignment. Park is a way to actually turn off the power while remembering the alignment. Once you have aligned, the motors are running to move the telescope to compensate for the Earth's rotation. You may not see any movement over a short period of time (ever try to watch the hour hand on an analog clock or watch move?). It takes 24 hours to complete one rotation, just like the Earth.
Subject:	Removing old data from auto star
Sent:	Sunday, January 23, 2005 17:09:49
From:	Mark Jensen (
I was wondering if I should remove old data about satellites so I can
have room to add new? I guess what I'm asking is there a list of
autostar items that are no longer relevant?
Thank you for your site it has been very helpful.
Mike here: Freeing up memory by removing "user objects" can certainly allow room to add more. But there is no list of "old data" that I'm aware of.
Subject:	Upgrade Autostar 2.6Ec ?
Sent:	Sunday, January 23, 2005 11:06:01
From:	Dan Williamson (
I apologize in advance if my question has been answered on the site.

I bought an ETX90 for my son. The Autostar version is 2.6Ec. Everything
seems to work reasonably well. The GOTO's are either good (in the
eyepiece) or fair (in the finderscope)  . . . depending upon the care
with which I set it up for a given night. Guided by the information
gleaned from your site, I'm sure it will get better.

Being a neophyte, and I'm not real certain about these terms yet, but I
seem to have some backlash, rubber-banding, and slow (then very fast)
movement using the arrow keys while centering. Again, with practice and
trial-and-error, I'm working with it. I'm not worried yet.

But two questions arise (and apologies if they are unrelated):

First, the Autostar version is 2.6Ec. Would upgrading help GOTO's? If
so, to what version? I can't find anything that tells me what I gain by
upgrading. From my general experience with software, upgrades are often
pointless and I don't want to upgrade unless I'm really going to gain

Second, I read some interesting material on your site regarding
trail-and-error adjusting of the alt-az percents. Is this something I
should actively pursue as a means of reducing the above-mentioned

I appreciate any guidance you can offer and, of course, your site is

Dan Williamson
Mike here: First off, do a CALIBRATE MOTORS and TRAIN DRIVES. That should solve rubberbanding. Second, upgrading to the current version on Meade's site is helpful (corrects bugs, adds features, and updates parameters). BUT do a RESET, CALIBRATE, and TRAIN DRIVES after ANY update.
Subject:	Alignment of ETX-105
Sent:	Saturday, January 22, 2005 03:36:09
From:	Tony Pagett (
A quick question from a newbie with a GOTO scope.
Everywhere I read it says I must align my ETX-105 manually and then
tighten the vertical and horizontal locks and that I must not use the
arrow keys on the autostar.

Question: If I followed the procedure below would this not work?

After basic levelling and aligning of tripod to north:

Manually find Polaris using arrow keys.
lower optical tube with arrow keys using small spirit level or a bubble
level eyepiece adapter.
Switch off Autostar.
Switch back on and enter time/date/daylight saving and easy align as
Mike here: Yes, that would work. By initially pointing at Polaris what you have done is locate True North on your horizon.
Subject:	re: Autostar badly overshoots during alignment
Sent:	Friday, January 21, 2005 19:13:22
From:	Richard Seymour (
Most likely the problem is dirt or grease masking one of the slots
in the encoder disk (a plastic gear-like disk mounted on one
end of the motor shaft).

You can possibly fix it yourself by opening the base and cleaning
it gently with a Q-tip.   

You can make a definitive test by setting up in Terrestrial mode,
then press-and-hold [mode] for 3 seconds.  Release.
Now scroll down to the Alt/Az display.

Now point the telescope at a landmark (great distance not required).
Note the Alt/Az readings.
Now slew the telescope a full 360 degree circle until it points
at the landmark -again-.

If it's a blocked encoder vane, the display will only have
incremented 350 degrees.

If it's two blocked vanes, or a broken/missing tooth, then
the display will only have advanced 340 degrees.

Remove any batteries before opening the base, be careful of
the battery-box wires (they're fragile), and the base is held
on by three screws (which may be beneath the rubber feet or
little plastic covers)

good luck
Mike here: If it is grease, it can sometimes be cured by unlocking the axes and moving the telescope slowly by hand, hard stop to hard stop, back and forth, several times. That can redistribute the grease.


Not from -between- the encoder vanes... (it might add -more-, though)

have fun
Mike here: Doing nothing or doing something; either helps or hurts!

And an update:

From: (
Boy, you certainly nailed it!
I did your Az/RA position encoder test and there WAS something blocking
the "teeth."

It turned out to be a tiny piece of grease-coated styrofoam (it looks
like) -- as from a packing "peanut."

It salvaged my winter vacation here in AZ (the ETX-125EC is my "travel

I COULD have found targets the "old way," but this is much nicer -- and
I don't have to send the scope to Meade when I return home (MN).

I had noticed the scope could TRACK at siderial rates OK, even though it
couldn't GOTO reliably. I'm guessing the encoders are NOT involved in

Thank you very much for all your help -- I've used your advice in the
past many times from the ETX archives, and references in Doc Grainer's
Art Kotz
Congrats on getting it going...

I had noticed the scope could TRACK at siderial rates OK, even though
it couldn't GOTO reliably.
I'm guessing the encoders are NOT involved in tracking??

Incorrect guess... the encoders are used, but it's only a 9% error,
which is roughly three times the "error" between the moon and the 
background stars (Moon: about a half-degree drift during an hour).

Plus, it's making the telescope too -fast-, and many folks find
their drives a shade pokey if they carefully measure them.

have fun

Subject:	Dead 497 handbox question
Sent:	Friday, January 21, 2005 12:16:01
From:	Damian Kessler (
First off, just wanted to thank you for the site-it's chock full of
useful information.  One has to read carefully and sometimes put the
pieces together to get it right though.

The other night prior to observing I connected the LXD-55 to initialize
and train drives prior to taking it outside.  It powered up normally and
I entered initial data until the 'Easy Align' prompt came up.  On
hitting 'Enter' here, the handbox display cleared.  I powered down and
tried again three times.  On the last try the handbox just displayed
partial characters until I powered off.  On the next tries, the box has
no response at all.  Cabling is good-tried two sets, voltage levels are
good-above 9V.

I tried firmware safe load and get no response at all from the handset
and the Updater  doesn't recognize the device as present.  So, anyone
else experience this? Any suggestions before I pay Meade to fix it?

Thanks again for the informative site.  

Damian Kessler
Mike here: Since the cables are good and since you have tried SAFE LOAD, I suspect the Autostar is dead. See the article "Testing Autostar Communications" on the Helpful Information: Autostar Info page; it might help.


Thanx for the reply-I figured that the handbox was DOA but I thought
there might be something I've overlooked.

As to trying to verify commo using Hyperterminal, I looked at that and
ruled it out since it acts as if it's not getting any power at all. 
Even the first times when the display went dead there was still a little
red glow around the edges of the display.  Now there's nothing.

Damian Kessler
Applications Engineer
SBS Technologies Inc.

Subject:	#497 Autostar software
Sent:	Thursday, January 20, 2005 07:49:41
From:	jacques..martinot (
I am a french astronom and I have got a LX90 Meade telecope and I have
problem with my handbox Autostar #497 software when I am in Polar Mount
Mode (all the fonctions are stopped).

So I am looking for a french version of the Autostar #497 software.

On your web site : I have
found the version #497 Autostar ROM 2.2Ft

But I am looking for a more french recent version (ie: 31F) do you know
where I can found it ?

Thanks for your help.
Mike here: Check this Meade Europe page:


Thank you for your help, so I found the good rom file on the site.

Subject:	Autostar keypad problem
Sent:	Thursday, January 20, 2005 08:29:34
From: (
Two of the kepayds on the Autostar that came with my DS 2114AT have
become detached. They are the up and down arrows at the bottom of the
keypad on either side of the Scroll? key.

I put the Autostar the wrong way round into the slot on the tripod tray
(keypad facing inwards). When it wouldn't come out I rather stupidly
tugged at it (tiredness is my only excuse) and these two keys came
loose. It's been pointed out to me that trying to glue them back in
could render the unit useless by permanently connecting the electrical

Although they work if placed back in their holes, the keys fall out if
the Autostar is anything other than horizontal. I asked my local dealer
(in the UK) and they said the only option was to return it to Meade in
the USA for repair , or to buy a replacement. Both seem like expensive
ways of tackling the problem. I'm wondering if anyone else has a cheaper
solution - assuming someone else has been careless enough to have this
happen to them.

From:	Richard Seymour (
About the only middle-of=the-expense pathway i can think of
would be to locate someone nearby (or BC&F, or Bill Vorce
at Telescope Warehouse) with a -dead- Autostar, and buy it
for the keypad membrane.

I had never considered this style of damage, and for completely
different reasons i use Velcro on the back of my Autostar to
hold it places, rather than the clip Meade provides (which
i've never installed... it's the least handy thing i've ever

Bill Vorce:

Be sure to remember to specify if you've got a 494 or 497-shaped 

good luck
Thanks for taking the time to reply to me. I'll start looking around for
a dead Autostar.

Congratulations on a superb website.


Gavin Sherriff

Subject:	Autostar badly overshoots during alignment
Sent:	Wednesday, January 19, 2005 21:57:43
From: (
I have an ETX-125EC with Autostar that worked fine about one year ago.
It has not been used since one year ago. Upon attempting to use it now,
the slew to an alignment star from the Home Position, badly overshoots
the target star by at least 30 to 40 degrees in azimuth (Alt-Az mount),
and about 20 degrees in altitude. Leveling and Home Position are
carefully set.

If I force it back to the correct position and synchronize the star
position, it says alignment successful. But any subsequent GoTo command
results in about the same large overshoot from the correct position.

I am using the Meade AC adapter for a power source, so depleated
batteries are not a problem. Date, time, site. mount and target entries
are all correct.

Is it time to try the Reset, and go through the training of drives,
etc.? Ugh!  --  or am I missing something?

Also, I notice that the Targets setting doesn't stay in the Astronomical
setting very well -- i.e. about half of the time when I go back to check
settings, it has reverted to Terrestrial.
Thanks for any help and thanks for a wonderful site.
Art Kotz
I calibrated the motors with the same results.
Mike here: Since you have done a CALIBRATION, I suggest doing the TRAIN DRIVES again. If that doesn't help, then a RESET, CALIBRATE, and TRAIN DRIVES. As to the astronomical settings, does the setting actually change or is it just that when you go to that menu item, it looks like Terrestrial is set? What has the ">"?


Thank you for the quick response.
The Targets setting actually reverts to Terrestrial -- i.e. the ">"
points to Terrestrial. I checked it again this AM, and it had reverted
to Terrestrial. I again set it to Astronomical and will check it later.
I'll try the re-training as you suggest, etc.
Thank you again, Mike for your help.
Art Kotz

And an update:

Status Report:
This is a second reply, since I've reset, recalibrated, retrained, etc.
with no success.

I called Meade Customer "Service," and they think it s a problem with
the telescope's position encoders.

Since I'm away from home for several months, I'll return it when I
return home. I HOPE it can track objects that I find by trial and error 
--  I'm testing that now.

Thank you again for your help and wonderful reference site.
Mike here: But does tracking continue even though the ">" shows Terrestrial (which is what would BECOME selected if you press ENTER)? I suspect you are just seeing the result of a "bug/feature" that has been around a long time.


As usual, your intuition and insights are dead-on!
Even though the ">" points to Terrestrial, the motors ARE grinding away.
The surrounding noise masked it normally, but after your letter, I
listened carefully and could, indeed, hear the motors tracking.

I CAN, of course, put it in Terrestrial mode for training the drives,
but after entering Astronomical once, it STAYS there even though the ">"
points to Terrestrial after a power-down. Must be a strange bug as you

Thanks again,
Art Kotz
Mike here: Just a point: there is no need to go into Terrestrial mode to TRAIN DRIVES.
Subject:	re: etx alignment question
Sent:	Tuesday, January 18, 2005 21:14:54
From:	Richard Seymour (
If you have properly done the   Setup > Telescope > Train Drives
procedures, the Autostar -learns- the amount of backlash in your gear
system, and properly accounts for the back-and-forth slewing.

Instead of playing with the blocks every time you go out,
why not put small bricks or concrete blocks IN your garden,
buried to depths which will give you "instant level" when you
place the tripod upon them?  
This would lower your setup time even more.

have fun
Thanks for the suggestion.

I will need to check with the head gardener about burying bricks but if
she agrees then I will do it!

Thanks again...

Subject:	re: updates for autostar
Sent:	Tuesday, January 18, 2005 21:08:44
From:	Richard Seymour (
To qualify Mike's answer:
it is not possible to update a 494's firmware programming.

it IS possible to update the User Objects (Comets, Asteroids,
Satellites, Tours) with the 506 cable.

it is also possible to control the telescope with the 506 cable.
Programs such as TheSky, StarryNight, Cartes du Ciel (free!),
and AstroPlanner (cheap!)  can do it.

However, you asked:
Meade Autostar # 494 to set it on equatorial mount

What model of telescope do you have?
Some models (such as the ETX60 and ETX70) can be set to Mount>Polar
with the 494.

There -is- a 494 (the front panel says "Starfinder") which is
programmed to work -only- with a German Equatorial Mount (GEM) for the
Meade 4504 and 114EQ/DH4 models.  These can be found on the
"used" market, or from William Vorce at Telescope Warehouse
(he will ship to Germany).

If you can get a 495 or 497 Autostar, they are easy to adapt to GEM.
have fun
Thank you for information

clear skies 


Subject:	updates for autostar
Sent:	Tuesday, January 18, 2005 14:41:51
From:	oliver peter (
heres Oliver from Gnzburg, Bavaria, Germany
I've seen your pages for the first time and im closed to set it to favourites...

can you give me some answers referring/in case of/ to an update for the
Meade Autostar # 494 to set it on equatorial mount.
can you help me?
clear skies
Mike here: There is no update for the #494 Autostar.
Subject:	etx alignment question
Sent:	Tuesday, January 18, 2005 12:56:23
From:	Kelleher (
Like many visitors to your site I've been working to optimise my ETX
set-up procedures with the aim of reducing time, increasing accuracy and
hence increasing productive time and the enjoyment factor of astronomy.

I have three markers in my garden that show exactly where the tripod
feet should stand to point exactly North. I keep the 'scope permanently
mounted on the tripod. I have shortened the spring under the eyepiece
holder on the Meade tripod which allows the holder to drop and rotate
without the screw needing to be fully undone. This in turn allows the
tripod legs to fold part of the way in which makes fitting through doors
easier when I carry the assembly in and out of the house. I use blocks
under the feet to get the whole assembly level and in all have reduced
setup time from ~30 minutes to ~10 minutes.

However, I have a question about alignment stars and backlash. I
searched your site and found the following:

Subject: Re: ETX-125EC report Sent: Monday, October 11, 1999 10:07:28
From: (Kevin P. Kretsch) Re: Wayne Gatschet's ETX-125
report, 10th October 1999. [...] When the alignment star is in the
eyepiece field of view, position it to say, the south east edge of the
vield of view. Then use ONLY the North and West buttons for centering.
This removes all the backlash in the gears before the alignment is
completed. Once centered using only these two keys, then press ENTER as
normal. I have found that this helps tremendously with accuracy. (As I
recall, somebody said that Celestron tell people to do this in the
Nexstar manual, so it's not just an ETX thing.) Regards, and clear
skies, Kev.

Should you do as suggested and position the alignment star in the south
east corner or do you think you should try to only drive in one
direction in Az and one in Alt once the scope has finished slewing to
the alignment stars?

At the moment I often overshoot on the first pass (because I'm impatient
and choose too high a slew speed!) and end up going back and forth a few
times to exactly centre the star but I wonder if this is adding backlash
errors to the alignment as the scope turns first clockwise and then
anticlockwise etc.

Any thoughts please?

Thanks for the great site and for any feedback...
Mike here: That is a valid technique but personally I don't do it.
Subject:	etx125 calibration procedure
Sent:	Tuesday, January 18, 2005 10:31:37
From:	M.Camargo (
Great site!! I just purchased a Etx125 and have a question for you. I
noticed in your web site that plenty of problems are resolved with
"calibrate and train drives" for a answer. I understand how to train the
drives but what exactly do you do to calibrate? In the Autostar(#497)
menu I have a option to "calibrate motor". When I try this option the
telescope moves side to side then up and down. Then it stops. Is this
option you talk about?? Thanks,

Mike here: Yes, that is the CALIBRATION step and that's all it does. Well, it does some other things so that the Autostar knows how to communicate with the motors.
Subject:	Select polar mode with my 20 button 497 Autostar controller?
Sent:	Monday, January 17, 2005 12:09:48
From:	James Edgar (
I'm a new user with a two day old ETX 105 EC.  I'm attempting to set-up
and align in polar mode, however, the instruction manual that came with
the telescope only describes how to set up using Alt/Az mode, i.e.
horizontal and pointing North.  I've noticed that the older? (8
buttoned) controller has screws in its back that one can remove to
select the Alt/Az or Polar mode.  I know how to set up the polar "Home"
position, but I don't know how to perform alignment in this position. 
i.e. the computer still seems to think its in Alt/Az mode.

How can I do this with my controller/Autostar version?


Mike here: You need to set the Autostar mount mode in Polar (from the Setup: Telescope: Mount menu). For how to align, see the alignment tips on the Helpful Information: Autostar Info page.
Subject:	re: ETX90 with #495 and resetting
Sent:	Saturday, January 15, 2005 10:53:30
From:	Richard Seymour (
If the "495" is happily running -now- with your ETX90,
then it already has been loaded with 497 code.
So a RESET should be safe to perform.

A normal 495 will flat-out refuse to operate if attached to an ETX90,
it will display "Use ETX Autostar with this model" and freeze.

If you have -that- situation, then a Safe Load  key sequence
at power-up will at least let you preform a firmware update.
That is: hold [enter] and [scroll down] as you apply power.
(read the "Damaged Handbox" help page in the Autostar Updater)

have fun

Subject:	re: Random Slews
Sent:	Saturday, January 15, 2005 10:48:08
From:	Richard Seymour (
What i detect a lack of in your tale of random slews as power levels
changed are the critical words: "performed a Calibrate Motors"

As the voltage levels change, the LEDs used in the encoders get
brighter or dimmer, which affects their operation.

I run my ETX with an AC Adapter which can put out 15v,
and from the interal AA cells which can drop to 8v.

If i get random slews, or "Motor Unit Fault" messages, my first
line of attack is to perform a Setup > Telescope > Calibrate Motor.

Excpet for cases of truly dead batteries, that fixes it (as it's
designed to).

For the background on "what's happening", read:

have fun
From:	Zoltan Beldi (
Hi Richard,

Thanks for your quick response. I'm sorry that I omitted to mention that
I had performed several complete resets, calibrate and train functions
thinking that it would be the solution as it has been for others.
However, it never appeared to for me.

I did also omit to mention that a little while ago I committed the
cardinal sin of connecting the external power reverse polarity.... My
neglect to mention that was mainly to not have to admit to being
basically stupid.

Nevertheless, as you can imagine, it took out the scope but the Autostar
appeared to still function. The damage to the scope appeared to be
restricted to a burnt track that supplies the Autostar power. After
replacing the track with some Kynar (wire-wrap) wire, function returned
albeit with the random slews.

So, I guess it's possible that I might have an electronic problem on the
drive board (though it does seem confined to the Dec axis in common with
many other posts on the ETX site) but I didn't have sufficient
operational experience with the scope prior to the burn-up to be sure
that it wasn't like that before.

At the present moment, the scope is working pefectly at any voltage
between 8V-11V so I'm probably not going to chase it any further unless
it starts to misbehave again. My post was motivated by trying to
understand the post by Joe Schlatter where he had exactly the same
problem on external, but not on internal batteries. It could be
postulated that it too was a "voltage' problem.

Anyway, i guess this is all good stuff on operational aspects of a great
little scope.

I really appreciate yours and Mike's input.

Kind regards,


Subject:	re: Autostar 497 error
Sent:	Saturday, January 15, 2005 10:32:59
From:	Richard Seymour (
It's -possible-  that the 497 keypad simply needs to be cleaned.

You can open the 497 by removing the 4 screws on the back,
popping the case open (catch the little red LED cover from the top!).
Then remove the two screws which secure the white display back reflector.

You can now lift the circuit card away from the rubber keysheet.

Gently clean the solder contact pads with a pencil eraser.
Gently clean the black rubber contact dots on the keysheet
with a dry Q-tip cotton swab.

Reassemble, being careful with the display's flexible cable,
and remember to put the red LED cover back in.

If there was a piece of conductive material/dirt across any key's
contact pad, it can prevent operation of the keys.

Ritz Camera is clearing out their 495's (which can be upgraded to
497's with a firmware download) for $40.  You can call their 800 number
 1-800-52FOCUS and ask for  part number 51-395-1079,
 which is the Autostar 495.  They had fewer than 20 left on Friday.

good luck
From:	Manish Panjwani (
Dear Dick,

Thank you very much for your very detailed response. Sorry for not
responding earlier. I was out of town over the weekend and saw your
email this afternoon.

I did exactly what you suggested - an lo and behold - the controller now
works! :)

I got the ETX for my neices in FL and was visiting them for a few days.
Hence, I really wanted to get everything up and running for them before
heading home. Now, thanks to you both, I will be able to achieve that

Thanks a million once again for your most gracious help.

Best wishes,

Subject:	Random Slews
Sent:	Friday, January 14, 2005 05:50:40
From:	Zoltan Beldi (
Firstly, thanks for the great site. Has been enormously useful.

I'm responding to the random slew fix posted by Joe Schlatter. I too had
exactly the same symptoms and like Joe, running from the internal
batteries "cured" the symptoms. So, like Joe, I ran an external power
cable to bypass the external plug. I add here that the problem
manifested itself when the ETX-90 was running from an external 12V
gel-cell battery via the external power jack. Imagine my disapointment
when the problem continued unchanged following the mod. I tried
everything I could think of, but no change.

Then, I downloaded a new version of firmware for the 497 controller
(updated to 323f) and voila the problem disappeared !  Why hadn't I
tried this before ?  It tracked flawlessly for the next few days until I
detected that the scope slew rate was slowing down. Checked the 12V
battery and found it was down to 7.8V, so that meant it had to go on
charge for a few hours.

The battery indicated 13.1V after the charge and I re-deployed expecting
a good nights observation. Yep, you guessed it, the mis-behavior
returned in all its former glory. However, this time I had a clue what
the problem was. It was a reasonable bet that the external voltage was
too high, so a quick trip to my junk box and out came a voltage
regulator that controls output voltage to 8.2V. On connection, no
further problems occurred and all function of the scope and 497 appeared
to work as advertised. Re-applying 12V re-introduced the random slew
every ten minutes or less.

My guess is that the high voltage is more likely the problem than the
connector. I would be interested to hear if any-one else has seen the
problem in this light.


Zoltan Beldi
Perth Western Australia.

Subject:	ETX90 with #495 and resetting
Sent:	Friday, January 14, 2005 01:35:05
From:	Cenneth Andersson (
I have and ETX-90EC delivered with Autostar #495.
If I make a RESET, will it then go back to a factory setting not
compatible with my ETX-90?
If so, what to do then if you can't connect for an update?
Which are the proper values to enter in
Az/RA Ratio, Alt/Dec Ratio,
Az/RA Percent, Alt/Dec Percent and
Tracking Rate for a ETX-90?
Thanks for any comments.
Cenneth Andersson
Mike here: According to Meade's info (, it is not compatible. You should update BEFORE doing the RESET. Then you will have a #497 and all will be OK.
Subject:	ETX70 and PEC
Sent:	Wednesday, January 12, 2005 11:28:53
From:	A. San Nicolas (
I recently bought a Meade DSI to use with my ETX70.  I've had some
success with it at exposures upto 21 seconds, 30 seconds works though
there is some elongation of the stars.  I decided to try the PEC in the
latest Autostar update (Build_32Ei, haven't tried the patch yet) to fix
this and get longer exposure times.  But when ever I turn on the PEC the
star drifts to the left on my screen.  If I've worked this out right it
means the drive is running slower with PEC on. I've trained the PEC,
updated the PEC, erased and re-trained the PEC, but I always get the
same result, drift with PEC on.  I have given my ETX a good tune-up
(thanks to your great site) and have achieved good polar alignment. 
GOTO's are good and the scope tracks well with PEC off.

Any help/tips would be much appreciated.  The weather has finally
cleared for the next few days, perhaps I'll try loading the patch this

Thanks, Tony.      

Subject:	Re: Fast Slew Disrupts Encoder Reading - ETX 125
Sent:	Tuesday, January 11, 2005 14:08:02
From:	Dave (
I've had the scope back and they fitted a new az gearbox.  That seems to
have done the trick by slowing down the scope in azimuth.  When I
disengage the clutch, it seems much "tighter" than before when it was
very loose.  Whether that is a long term solution I don't really know;
if it does "loosen up" as it was before, I might get the same problem
back again.  Any idea how long the scope should take to complete one
revolution on maximum slew speed please.  At the moment, mine takes 1min
17sec. Power pack voltage is 12.8v.  Does that seem about right?

Thanks very much for your help, it is a great site and I don't know what
the world's ETX owners would do without you.  Keep up the good work!
Dave Owens
Mike here: I haven't timed mine but that sounds about right.


From:	Richard Seymour (
"Maximum speed" is purposely undefined by Meade (but hinted at
somewhere in the specs).   Max Speed is simply the battery voltage
applied to the motors.  So the power supply will directly affect it.

Speed 8 is 3 deg/second, so a full 360 spin
would be 360/3=120 seconds (2 min).
So 1 min 17 sec certainly sounds reasonable.

> At the moment, mine takes 1min 17sec. Power pack voltage is 12.8v. 
> Does that seem about right?

By the above, yes.

have fun

Subject:	RE: Motor Fault by one of reader
Sent:	Monday, January 10, 2005 17:14:58
From:	Leung Henry (
First thing first. GREAT WEBSITE. 

I encountered the same problem four months ago. I tried everything.
Nothing works. Lucky for me, it was under warranty. I suspect is the
software for the 497 controller. Try to download the latest patch before
senting back to Meade for service.


Subject:	RE: ETX125 Easy Align issue
Sent:	Monday, January 10, 2005 16:59:39
From:	Arthur Caracciolo (
I went thru the train drive sequence this afternoon and I notice
something it maybe because I wasn't rushing, but when the telescope
moves it is very slow and quiet, compared to when it is moving to
alignment stars. I think it was moving before and I didn't notice it, I
am embarrassed :-)

The telescope is probably in better shape now for having gone thru the
training anyway. I am about to go out now to see if I can have a session
it was clear before

Thanks again
Arthur Caracciolo
Mike here: Yes, it is quiet and slow. You can speed it up but I don't recommend that.
Subject:	autostar 494 case
Sent:	Monday, January 10, 2005 11:53:26
From:	Jack O'Connor (
The keys on my etxat70 Autostar 494 were requiring that I press them
very hard to the point where they almost wouldn't respond at all.  I
know how to clean them but I couldn't figure out how to open the case. 
I emailed you and you replied, (very promptly, thank you), that I should
just pry it apart with an appropriate tool.  I did so and it worked!

I cleaned the keys and reassembled the case with rubber bands to hold it
together and everything works fine.

However, the rubber bands are just a band-aid fix.  I noticed when I
took the case apart that it had been glued together at the seam/joint
between the two halves of the case.  I would like to glue it back
together but I don't know what kind of glue to use.  I assume that I may
have to repeat the cleaning procedure at some future time and I want to
use the proper type of glue - one that will safely hold the case
together, but also allow me to take it apart if I need to clean it

Can you tell me what kind of glue Meade uses for this purpose?
Thanks ......... Jack O'Connor
Mike here: Glad that you got the Autostar working reliably. As to the glue, I don't know what Meade uses. But obviously you should not use model airplane (plastic) glue or Super Glue.
Subject:	Re: AutoStar #495 vs AutoStar #497
Sent:	Monday, January 10, 2005 00:59:16
From:	Cenneth Andersson (
Thanks for your answer.
I thought maybe there was a difference in memory size.
Model #495 has a database with 1500 object while #497 has 14000 objects.

Since they differ in price with $50 and I have bought and paid mine as a
#497 I was interested to see how I could check what is actually

Cenneth Andersson
Mike here: The original software had a small number of objects; later versions increased that to >30,000.


Thanks, but, just to get it definitely right.
I understand your answers as there are no hardware differencies
whatsoever. It is just a matter of software, and, the software and the
database in #495 can be updated to the 30 000 objects in #497 through
the Meade site.

I will understand if you find me a bit meticulous.

Mike here: Yes, the #495 becomes a #497 after updating. All the same objects and capabilities are there. For more info, see the article "Autostar Models" on the Helpful Information: Autostar Info page.
Subject:	AutoStar #495 vs AutoStar #497
Sent:	Sunday, January 9, 2005 14:33:03
From:	Cenneth Andersson (
I have seen that there are two different models of AutoStar.
Model #495 and #497 respectively.
How can I find out which model I have?
Are there any differencies regarding their connection to a PC?
Thanks for any comments.
Best regards
Cenneth Andersson
Mike here: Essentially there is no difference. You can upgrade the software that shipped on the #495 to make it a current #497 using the software from Meade's site. Once upgraded you can use any #497 PC/Mac software.
Subject:	RE: ETX125 Easy Align issue
Sent:	Sunday, January 9, 2005 11:28:26
From:	Arthur Caracciolo (
Great site appreciate all your hard work maintaining it
I have a new ETX125, when i try to do an easy align (I think my home
position is correctly done) it get pretty close to the first star, but
when I try to move it to center it nothing happens when I push the arrow

What am I doing wrong?
Thanks in advance
Arthur Caracciolo
Mike here: Have you tried to increase the slewing speed?


As a matter fact yes, when I pressed 9 it said max?
But I am not getting movment

Arthur Caracciolo 
Mike here: Have you done a CALIBRATE and TRAIN DRIVES?


That is my next step, it got dark already, and its cloudy nights
I think I try training drives tomorrow in the daylight

I'll let you know thanks again

Arthur Caracciolo 
Mike here: Working with the telescope indoors is perfectly acceptable when learning a new system.
Subject:	Question on aligning the AutoStar Program
Sent:	Sunday, January 9, 2005 02:49:36
From:	Steve Horner (
Excellent Site, It gave me hours of insight before buying the ETX90. I
recieved the ETX90 a couple of days ago, but have been unable to get the
AutoStar functionality to work. When it goes to look for the first star
it starts pointing directly upwards, eventually it collides with the
side brackets and gives a fatal error on the screen. Any thoughts. Ive
reset it a couple of times with the same results.

Steve Horner
Mike here: Did you CALIBRATE and TRAIN DRIVES?


I calibrated the scope, and it seems to have fixed my issue.
Steve Horner
Mike here: Thought that might be the case.
Subject:	Thanks for your answer.
Sent:	Thursday, January 6, 2005 08:18:26
From:	chasiotis elias (
Mike thanks very much for your help, now everything is o.k.
Mike here: Glad that solved the rubberbanding.
Subject:	re: Fast Slew Disrupts Encoder Reading - ETX 125
Sent:	Wednesday, January 5, 2005 21:18:22
From:	Richard Seymour (
I agree with Clay: dirt on an encoder vane or two.
(in Azimuth, this will create -exactly- a ten degree error in 
readout for a 360 degree spin, if one vane-gap is occluded)

But the reason i wrote is to clarify the internals:
Meade does NOT regulate the 12v line, except for bringing
it down to 5v for the electronics.

The motors (and LEDs) are fed (via FETs) full battery voltage,
 whatever it may be.   Thus the need to Calibrate if you change
power sources (Mains adapter vs. battery, for example).

have fun
From:	Dave (
Hi Mike and Richard (thanks for your input)
As a final test before sending the scope back, I decided to carry out an
accuracy test with the external power pack connected.  I picked a spot
and lined the the eyepiece cross hairs on it, with the az readout
showing 000.00.  Then I slewed the telescope at Speed 8 clockwise 360
deg whilst monitoring the Az readout on the handset.  When I had made a
full rotation, the readout was 000.00.  It was as error-free as I could

Next having selected Speed 9, I reversed the rotation 360 to get back to
the beginning.  The readout should have been 000.00, instead it was
still reading 240 deg!!!!  So, it is definitely something to do with
motor speed.

Thanks both of you for your help, I will keep you informed as to
progress.  The importers here are very good and I expecte to have the
scope back within three working days



Subject:	re: Autostar and alignment troubles
Sent:	Wednesday, January 5, 2005 21:11:45
From:	Richard Seymour (
First off, the Autostar cable is -definitely- bad.
Either call Meade for a replacement, or build a replacement.
The cable should be reversable end-for-end without a change
in the operation of the system.  The fact you can't shouts 
"bad cable" (and it could have pins/wires shorted together,
as well as open).

Replace the cable before making any other judgements about 
the system.

It could also be a -combined- problem: such as a mis-plugged
connector -inside- the telescope base, plus a flakey HBX cable.

(p.s. Rigel and Betelgeuse are too close together for a 
good alignment... try Betelgeuse and Kocab)

have fun
From:	Bob Gutkowski (
Thanks for the advice.  I figured the cable was bad.  I made a new cable
from a LAN cable I had (following the directions on your site).  I can
now reverse the ends of the new cable without issue.  One question I
have - does the Autostar recieve feedback from the motors as the scope
is rotating or is the distance of rotation souly determined by the
Autostar.  If the problem continues and elimiting the cable, would the
issue be with the Autostar or the telescope.  Hoping for some clear
skies this weekend to try everything out.  Again thanks for the
Mike here: No direct feedback; the Autostar counts the "pulses" from the encoders.


Er, "both" (and Mike's answer could be wrong or right, depending upon

The Autostar sends a speed command to the motor controller cards
(which are inside the telescope).

The actual count-the-ticks circuitry is on the motor controller 
cards themselves.   Every so often (at least once per second)
the Autostar asks the motor controller card how many ticks 
have accumulated since the last request.  It receives an 
absolute number (the in-motor counters don't clear).
A full rotation of the telescope (lock to lock) exceeds the
in-motor counter's capacity, so the Autostar does the "carry"
operation to maintain the grand total.

The Ratio settings are actually "ticks per arcsecond", and
the student is welcome to convert those to how many ticks
are a full circle (or, again, lock-to-lock) for -your- 
telescope.  (example: an ETX90 can turn about 500 degrees,
and it can maintain sub-arcsecond accuracy through that 
entire range, with a Ratio of about 1.36 ticks per arcsecond.
That's 500 (degrees) * 3600 (arcsec/degree) * 1.36 ticks/arcsec
which yields 2,448,000 ticks ... 
and other models can generate over four times that number.

The speed communication from the Autostar to the motor controllers
are roughly: an address byte, a command byte, 3 data bytes, 
and it expects an acknowlegement byte.
The encoder communication is controlled by the Autostar,
so it sends an address byte, a command byte, and then expects
4 bytes to return (three for the encoder count, one status byte).

But the Autostar does not watch a continuous encoder "tick"
stream over its cable.

have fun
Mike here: Thanks for the clarification/expansion Dick!
Subject:	Question about a serious tracking problem.
Sent:	Wednesday, January 5, 2005 06:48:19
From:	chasiotis elias (
I want to ask you about a tracking problem that my ETX recently had.
After i center the image and usually after repeated use of Enter to Sync
mode (at high magnification video capture this is necessary), the image
is gliding slowly but then is suddenly pulled back to the initial place
with violent move and a small noise inside the motors(usually every ten
seconds). This makes planetary photography very difficult because
Registax cant properly align the frames and the result images are awful.
It does not happen every time but i am worried if i have caused a big
problem by overdoing it with Enter to Sync.
                                              Thank you in advance.
Mike here: I doubt you have caused a problem but heavy use of the SYNC command. But does the problem happen even when you don't SYNC? Anyway, this sounds like "rubberbanding"; the cure is usually to reTRAIN DRIVES.
Subject:	Motor Training
Sent:	Tuesday, January 4, 2005 01:45:25
From:	Terry Godfrey (
I train the drives on my ETX125  (Autostar 2.6) every few months, more
out of habit than necessity, however I was surprised to read in your
book (Maintaining and Retraining on page 185) that it is necessary to do
a RESET first. I had always assumed that a fresh training session
overwrote any previously stored information.

Could you clarify the situation as my Meade manual does not mention the
need for RESETing.

Best regards

Terry Godfrey
Oxford, UK
Mike here: RESET only needs to be done when things act up. But you should CALIBRATE whenever you change power sources, including changing batteries.
Subject:	Autostar and alignment troubles
Sent:	Monday, January 3, 2005 21:32:32
From:	Bob Gutkowski (
Great site. Need some advice. Just got an EXT-90 with an Autostar 497 as
a gift. I've done a Calibrate and Train Drives (both axis) a few times.
Everythings seems to go find. When I try and Align the Autostar (2
stars) the problems begin. I set up the telescope by the book (north /
level). The unit always finds the 1st star with no problem -say Rigel
(the telescope is turning clockwise). When the Autostar moves to select
a second star (turning counterclockwise) no star to be found in the
site. I manually selected 2 stars - Rigel - no problem. Then I selected
Betegeuse, expecting a movement to the east. The telescope swung around
to allmost NE. In some cases the telescope continues in the
counterclockwise direction until it has a hard stop. The manual
controlls for moving the scope operate without error.  The batteries are
new.   I'm trying to determine if its the Autostar, cable or the
telescope. I've checked the pins in both the Autostar and the telescope
- they look OK. I've ohmed the cable - no problems found. The solder
joints on the autostar look good. Haven't done anything to the telescope
other than checking if the pins are bent. Here's the kicker - If I
reverse the ends of the cable, the Autostar is dead. I can reverse the
ends again and I'm back to where I started. I tried playing with the
connectors - no change. It seems the Autostar dosn't know how far the
telescope is turning in the counterclockwise direction.

Have you heard of this issue?
Mike here: A question: Have you done the rotation to the first hardstop then back CW about 120 degrees to North? Also, when manually selecting Alignment Stars, they need to be at least 90 degrees apart. Finally, if those don't help, do a RESET, CALIBRATE, and TRAIN DRIVES. For more on alignment tips see the Helpful Information: Autostar Info page.


Thanks for responding so quickly.  I have been rotating the telescope
all the way CCW to the hard stop and then CW until the fork was aligned
with the Computer control.  I did a Reset, Calibrate and Train Drives
again (both axis).  Still having problems when the scope moves in the
CCW direction. The moves too far CCW - missing objects by 40, 60, 90 and
even 180 degs. - and the distance seems to be randam.  When selecting a
1st alignment star that requires the scope to rotate CW, the scope is
always right on.  If the 1st star is in the CCW direction, the scope
usually doesn't even come close. Am I still missing something in the
setup? Any other suggestions?

Thanks for the assistance.
Bob Gutkowski
Mike here: This is odd. What happens if you do the Easy Alignment?


When I did Easy Aligment the scope usually started to rotate in the CW
direction first. Always lining up close to a star (Rigel in one case,
which I know). With some slight adjustments, the star was centered. The
scope would then rotate in the CCW (I can't recall what stars - did this
a few times) but there never seems to be a star in sight. In one case
there was a star close, so I centered that star (not knowing for sure if
it was the correct star but it was the only one even close). I selected
Rigel as an object to view. The scope rotated CW but not even close to
Rigel. I then selected Saturn knowing it was in the east. The unit
rotated almost completely north. In one case when using the Easy
Aligment and the first star was centered after rotating CW (Southeastern
sky). When the scope slew to the 2nd star CCW, it actually rotated
compltely around and hit the hard stop in SW sky. The scope was aligned
correctly (rotating fully CCW and then back to have the fork aligned
with the Computer Control). The Autostar sounds like a great feature -
capablity to track an obect and find new objects. It's something I'd
really like to have work. Going to have some cloudy skys for the next
few days. Should have a chace to check the night sky out again this
weekend. I did a test the other day selecting Rigel as the first star
and Deneb as the second star. Dialed in close to Rigel no problem,
slewed to Deneb in the NW sky. I didn't think it was even close but I
selected the star closest to center. I then proceded to togel between
viewing Rigel and Deneb beleiving the scope should turn CW and CCW
approxiately the same distance. The scope did not find Rigel at all -
stoped in the eastern sky. I noted how many degres the scope turned CW
(110 deg). Then when slewing back to what the scope selected as Deneb
the scope rotated about 130 deg. Using this new starting point, the
scope would always turn 110 deg CW but would progressively turn further
and further in the CCW. Eventually the scope hit the hard stop in the
CCW direction. This was gift from by father inlaw. I going to see him
this weekend and have him try all the adjustment from the top (just to
make sure its not me).

Bob Gutkowski
Mike here: Since you did not get the "Alignment Failed" message the Autostar must think things are OK. So, at this point one thing to try is reloading the Autostar software. You will need the Windows Autostar Update application from Meade's site (or the new Mac OS X app) and the 3.3Ef ROM file. You will also need a #505 serial cable (and perhaps a serial-USB converter). You can buy or easily make the cable (see the Helpful Information: Autostar Info page). Alternatively, you could contact the dealer for an exchange.
Subject:	Fast Slew Disrupts Encoder Reading - ETX 125
Sent:	Monday, January 3, 2005 14:45:01
From:	Dave (
I've had a look at your site (brilliant) but I can't find anything on my
specific problem.

If I use an external power supply (either mains powered or a battery
pack) both nominally 12v (but in effect around 12.85), the slew speed on
the "goto" function is so high that the azimuth encoder does not read
correctly.  I tested this by checking the azimuth readout on the
Autostar after holding down the mode key and then scrolling to display
Alt and Az readouts.

If I use the eight AA batteries, all is well, but with a full 12v (or
just over), it just won't keep up with the speed.

I have switched the telescope to "quiet slew" which slows it down so
that all is well, but it seems a  bit "naff" to be to have to do this.

When using the Autostar to slew the scope, I only get the faulty reading
when on the highest speed (9), 8 and below are fine.  Of course the
problem is that on a GOTO, it automatically selects the highest speed to
initially slew the scope. Consequently it just keeps driving in azimuth
as the encoder can't detect when the correct position has been reached.

Any ideas please?  I shall keep "quiet slew" selected for now so I can
use my new 12v Battery Booster Unit.

Best regards and thanks for a great site.
Dave Owens
Mike here: When you switch power sources, are you doing another CALIBRATE and TRAIN DRIVES? You should.


Hi Mike, thanks for your prompt reply.  I tried that and it's still the
same. It will only work on "quiet slew" or manually on any speed less
than 9.  On "goto" is misses everything completely and on manual slew on
high speed, I can actuall see that the readout is incorrect when it is
slewing.  Can you suggest anything else please?  I heard that Clay
Sharrod runs his at about 18v!!! so I don't think it's the battery as at
max it is only 12.85v. 

I really don't want to be running the system on AA batteries as I will
want an electric dew system one day.

Could this be a system fault or is there perhaps another answer.
Mike here: Have you tried updating to version 3.3Ef (even if that version is already installed)? Maybe the Autostar is slightly corrupted and reloading it would fix it. Otherwise, I'm at a loss as to the cause.


Thanks Mike, it's still the same and any "landmark" tests are around 20%

I think I'll return it to the retailer and get them to sort it out.

Dave Owens
And this from Dr. Clay:
From:	P. Clay Sherrod (
Hello Dave...
Interesting issues here.
Note that I have used, and recommend using, the ETX with voltages up to
15.2 but NO more than that; 18 V will fry the system very quickly.  At
about 13.5 to 14.5 v. is optimal.

However, the problems you are encountering are not voltage related and
since speed seems to be a major factor I suspect very strongly that you
have debris or grease in either the encoder tick wheel or the sensing
light which rides over the wheel; investigate this in the base of the
scope very carefully.....the small battery wires will break if you are
not careful with the bottom plate.

The encoder wheel is a small white spoked wheel far to the lower left of
the entire motor/reducer gear assembly and up in the far recesses of the
base...use a flashlight to investigate;  you can turn the encoder wheel
by turning one of the larger plastic gears that protrudes from the
plastic reducer gear housing to inspect the total span of the you have grease or a piece of lint in there.

Let me know what you find.
Dr. P. Clay Sherrod
Arkansas Sky Observatories
Harvard MPC H41 (Petit Jean Mountain)
Harvard MPC H43 (Conway)
Harvard MPC H44 (Cascade Mountain)
And an update.
The UK distributor is picking it up tomorrow. He has come across
something like this before.

As an ex-control systems engineer, I'm assuming that there should be a
12v regulator somewhere on the electronics board so that if a car
battery or mains adaptor is used then, it will regulate down to 12v
exactly from a nominal input voltage.  If this regulator was not working
correctly then of course any external input voltage above 12v would
certainly cause the electronics to malfunction.

I'm sure they will fix it and naturally, I'll let you know the outcome.


Subject:	Re: Autostar instructions
Sent:	Saturday, January 1, 2005 08:45:07
From:	Robert Stenstrom (
No luck with calibration and training. Just bought the autostar on
astromart. Contacted the seller yesterday. He used it with an etx 70ec.
Could this be the problem? Bob
Mike here: I presume it is a #497 Autostar (the model with the number keys). Have you set the telescope model and mounting mode to be your telescope? Did you try the RESET?


How do I command reset on the autstar? I preuiously set the model
andmounting mode. Thanks for your help so far. Bob
Mike here: SETUP>RESET
Subject:	Autostar Easy align problems
Sent:	Saturday, January 1, 2005 07:54:00
From:	Steve veness (
just wondered if anyone can help with a problem I have come across since
downloading the latest Autostar software (33Ef I think).  I have
retrained the motors but when I try Easy Align the scope slews towards
the first star but never gets there & never beeps to ask me to centre. 
Instead it continues to slew by 7 or 8 degrees RA/Azimuth at the time
then pauses for 5 seconds before slewing again, and so on.

Because  the weather has been cloudy since Christmas (I live in the UK!)
I was doing a 'dummy' align during the day but I am sure I have done
this before with no problems.

Any advice would be gratefully recieved.
Steve Veness (using my wife's email, hence Judy@.... !)
Mike here: Do a CALIBRATE and then TRAIN DRIVES. If that doesn't solve it, do a RESET. This will restore the Autostar to "factory defaults" so you will have to enter your location, and do another CALIBRATE and TRAIN DRIVES.


Thanks - will try that.

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