Last updated: 30 April 2008

LXD55 8sc logo

This page is for user comments and information of a general nature or items applicable to all LXD55 and LXD75 models. 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:	Clay's Kochab's Clock question
Sent:	Tuesday, April 29, 2008 13:02:38
From:	Oz (wforacer@rocketmail.com)
I am new to GEM mounts, I have a LXD75.

I read the link below and "think" there is a problem with it, but it's
probably just me.

The NCP is BETWEEN Polaris and Kochab, in the 2nd and 3rd  picture I
think is incorrect. I think the counterweight bar should be 180 degree
from what the picture is. This way, the little circle is placed on
Polaris and the NCP will be BETWEEN Polaris and Kochab. The way the
current picture shows is the NCP is not between Polaris and Kochab.

Please correct me if wrong.

Thanks for all your great info on your web site!

Clay's Kochab's Clock
Polar Alignment Method
For The German Equatorial Mount

Mike here: Do a search on the Site for "Kochab clock lxd". I think maybe your question will be answered.
Subject:	LXD75 hypertune kit
Sent:	Tuesday, April 29, 2008 09:34:46
From:	Andrew Dumont (bongo69@earthlink.net)
I am thinking of performing a at home hypertune on my LXD75 and have a
couple questions.Will performing the hypertune dramatically improve
tracking for longer exposure times.Right now,my scope will accurately
track for about 65 seconds (prime focus) before I begin to see some star
trailing.How long can I expect exposure times to increase after the
hypertune?.Also,when I goto a object,the scope will slew to the object
but,is barely in the FOV and sometimes I have to perform a spiral search
to find even the brightest objects.Will the scope (after the hypertune)
accurately point to the desired object without guessing if the object is
in the FOV.I realize that a good polar alignment is necessary for real
long exposures but,at the moment I don't own a lighted reticle for
performing a PEC and was just wondering how large the improvemnt will be
AFTER a hypertune.I own a Meade DSI and have used it a few times for
brighter objects but,I want to image those real faint fuzzys.Which is
tough when one doesn't know if the scope has slewed to the object
Andrew Dumont
Mike here: I don't have any direct experience with the Hypertune but from reports I've read on the Yahoo Groups forum it is worthwhile. There are many variables outside control of the mechanical improvements that affect tracking. So whether it would improve or not, hard to say. When I had my LXD75-8"SC (before it was stolen) I could get fairly good tracking for several minutes with a piggybacked camera but still needed to manually guide when doing astrophotography at prime focus. That's why I got the Meade Off-Axis Guider and used it with an illuminated reticle eyepiece. As to GOTOs, with a proper setup and alignment you should be able to get objects into the 26mm eyepiece FOV. I did. Have you done a CALIBRATE MOTOR and TRAIN DRIVES (both axes)? Also, you might want to check out doing the LXD Adjust (discussed in the LXD manual appendix).


I can get the object in the FOV when using the 26mm eye piece (actually
at the very edge of FOV) but,would like to get it closer to center.I
have had this scope and mount for almost 3 years and have performed zero
maintanane on it.With the economic stimulus checks the government has
issued.I thought I would take the opportunity to pay for the fix.Using
the rest of the money for bill payments of course.One thing I am curious
about is polar alignment.The scope is dead level and balanced and I put
Polaris in the center of the circle of the polar alignment
scope.Now,when the scope is in the home position,shouldn't Polaris be
close to center when looking through the OTA?.I find Polaris through the
main OTA to be on the very edge of FOV,even before alignment.Using my
logic (which is Nothing to brag about),if Polaris is barely in the FOV
and after alignment,the desired object is the same area of FOV.Wouldn't
adjusting the saddle so Polaris is near center in the FOV,better the
chances of getting the desired object near center also?.
Oh and yes I have calibrated the motors and trained the drives.
Mike here: Two points: Polaris should NOT be in the center when the mount is polar aligned. See the article "Using the Polar Alignment Scope" in the LXD55 / LXD75 Information section on my LXD Home Page. Second point, if the telescope optical axis is not parallel to the mount's Polar axis, then there will be a difference in where each is pointing.
Subject:	Autostar 497 erratic behavior
Sent:	Monday, April 28, 2008 12:58:44
From:	Kirk Stenvall (kirk@stenvall.net)
Thank you so much for providing your wonderful website to us lxd55/75
users. I have a problem that I can't seem to find a solution for. I've
searched the internet, read your site and several others, but nothing
I've tried has worked.

I purchased a used LXD75 6"SN several months ago. Not long after buying
it, I threw caution to the wind and mounted a 10" newt on it, which
needed a total of 35lbs. of counterweight, plus the extra weight of the
OTA. I knew I was pushing the envelope, but making sure that balance was
as close to perfect as I was able to achieve, I set it up. I've had it
out several nights a week since then, and the mount/Autostar has worked
flawlessly -- with this mammoth OTA on it!

Several nights ago I added a DSLR to the focus tube (after lobbing 3.25"
from the OTA to achieve back focus) and rebalanced. After slewing
to/tracking several objects without a problem (as usual), I began
receiving "motor unit fault" errors. I was running on 8 D-cell batteries
so the first thing I did was replace the battery back with the power
adapter that came with the scope (from Meade) yet oontinued to receive
the "motor unit fault" errors. Assuming the extra weight of the DSLR was
the straw that broke the camels back, I tore everything down and decided
that I'd use the original 6" OTA for photography and not push the mount
any further.

To get to the point, my Autostar controller is now not working properly.
When powered up, sometimes it goes directly to "testing motors" followed
by "motor unit fault". Sometimes when powered up, the Autostar goes
through normal procedure: date, time, daylight savings, etc. Then when
it gets to "align", and I attempt to do so, the motors don't respond.
The controller will display "slewing", but the mount just sits there.
Sometimes if I leave it powered up, for instance while I was downloading
and replacing the most recent Autostar update, the motors will engage by
themselves for several seconds, then stop. Then several minutes later,
one or both motors might engage for several seconds then stop. Like it's
receiving something from Autostar.

I'm sure it's the Autostar and not the motors. I have an old DS114 with
the old Electronic Hand Controller (no goto) and when I attach it to the
mount, it operates both motors at all speeds correctly.

I've checked the encoder wheels and they seem fine, other than being at
the far end of the shaft (not in the middle). I've reset the Autostar
many times and replaced the Autostar software (43Eg). I'm at a loss. I
would have thought if the overbearing weight would have done anything,
it would have burned out a motor, not affect the autostar.

Can you offer any suggestions?

Thank you so much for you time.

Kirk Stenvall
Mike here: I doubt that you damaged the motors or the gears. But with that extra weight you might have overtightened the axis locks. But that wouldn't cause all the symptoms you are seeing. It almost sounds like an intermittent connection between the AutoStar and the mount. You might check the pins in the jacks and on the AutoStar cable connectors; they should be clean, not bent sideways, nor too depressed. If your AutoStar cable does not have the ferrite core on the cable then try reversing the cable. If it does have the core, I have found that it needs to be at the mount end, not the AutoStar end. Beyond that, perhaps our resident AutoStar expert Dick Seymour has some thoughts.


Thank you so much for the quick reply.

I'm assuming that since the old controller operates the mount, that the
gears and motors are OK... which is great news! I checked the connectors
and all appears to be fine. I've dropped the Autostar several times onto
the asphalt (that coil cord is suicidal), but don't recall doing so the
night that this all began happening. But perhaps those drops have
finally affected it's performance.

I'll wait to see if Dick Seymour has any ideas.

Worse case scenario, I purchase a new Autostar, which is much better
than replacing the entire mount.

Thank you again!



From:	Richard Seymour (rseymour@wolfenet.com)
I agree with Mike's diagnosis: it sounds like a bad connection
between the Autostar and the motor cards in the mount.
("bad" can include an open wire, but also two of the leads 
short-circuiting to each other).
Swapping the handbox cable end-for-end is the first and simplest
thing to try.  Pushing and wiggling the connectors is number two.

good luck


My thanks to you both for your time on this matter.

Swapping the ends of the cord changed nothing. However, even though it
doesn't fix the erratic behavior,  wiggling and pushing one end of the
cord does give a different response.  The Autostar will either present
"Testing Motors" then the error and nothing more, or, after wiggling an
end it will present "Testing Motors" then the DEC motor will run for a
second, then the error appears.

Fortunately, I work for a company that has all the necessary parts and
tools to completely replace the connectors on both ends of the cord.
I'll do that tomorrow at work.

Thank you again. I'll let you know what happens.



If you can hold one end steady...
does it matter -which- socket/plug gets wiggled?
Some 497's had poor solder joints where the RJ45 socket
attached to the circuit card.
Re-making (and frequently, just re-crimping) the cable does
frequently fix problems like this, i'm glad you've got access
to the tools and parts

good luck
Yes. It does matter. It's the end that plugs into the housing that
contains the computer control panel and RA motor. To try and verify
this, I switched the cord around again and after one "testing motors"
display and the dec motor going for a few seconds, then a fault, I
turned it off then back on again and the "testing motors" appeared but
neither motor engaged. Then the Autostar went into the "Enter Date"
screen and all the way through to "Align: Easy". I pressed Enter, it
selected a star, displayed "Slewing", but nothing engaged. I then
wiggled the connector plugged into the control panel and the Dec motor
began spinning. It spun for several seconds then paused. Then spun for
several seconds then paused. This continued until it went nearly 360
degrees at which time I turned the power off.

Do you think it's safe to assume that the extra weight on the mount was
not the reason for these current problems? The photos I get from the 10"
are so much more superior to those from the 6". If however, it's not
safe to assume that, I'd rather have many years of enjoyable 6"
photographing than a shorter time with the 10" because I've overloaded
my mount.

Kirk Stenvall wrote:
> .... I then
> wiggled the connector plugged into the control panel and the Dec motor 
> began spinning. It spun for several seconds then paused. Then spun for 
> several seconds then paused. This continued until it went nearly 360 
> degrees at which time I turned the power off.

That is a -specific- symptom of an open connection to the motor control
card... (the run/stop/run/stop)... you can demonstrate this by
powering up the scope with the Autostar completely detatched.

No, i don't think "overloading" had any contribution to this.

But i do think that, after you have made a new cable,
  you may have to check whether or not the pins (wires)
in the mount's socket are truly reaching the plug's pins,
and also the solder joint from the socket to the distribution
panel, the seating of the DEC motor cable connector on that
distribution panel, and perhaps whether or not there's a
crack in any of the copper traces on that panel.

But first try fixing the cable, and checking the contact
pins in the socket (disconnect power supply, and then try
-gently- pulling them a little (-little-) further up so
that they reach into the grooves of the plug just a smidge

good luck
Mike here: I doubt that the 10" Newt weight did anything. Afterall, the LXD75 can handle (barely) the Meade 10"SN.


Okey dokey. I'll check and double check everything you've suggested,
obviously doing the easiest first (cable/pins). Then work my way down
the line.

Thank you both so much for the time and effort you've put into helping
me, and others. I'm encouraged that my night time activities won't be
curtailed for long!

I'll certainly let you know how things turn out.



We've not known each other very long, but I feel comfortable in saying
that I love you both. LOL.

I tested the cord that connects the Autostar to the controller box on
the mount and it tested faulty on 2 wires. Using regular Cat-5 ethernet
cable, I created a new cable using the cord connectors as a guide. After
connecting the Autostar to the mount with this new cable, and resetting
the Autostar, it's working perfectly!! It was a bad cable/cord.

I've not had it out under the night sky yet, but I've done several mock
alignments indoors and it appears to be slewing automatically and
manually the way it should.

I simply can't thank you both enough for your guidance. Thank you. Thank


Subject:	lxd75 mount
Sent:	Tuesday, April 22, 2008 14:19:08
From:	starman2@comcast.net (starman2@comcast.net)
I have a question for you. My lxd75 mount, when slewed to the west,
after releasing the button. will slowly slew back to the east, for a few
seconds. When the east button is pushed, This does not occur. Nor does
this occur for the north or south buttons. The weird thing about this
is. It does not seem to be a backlash. I don't know if, the motor is
actually rotating the drive gears. But it smoothly rotates back a few
degrees. Before coming to a rest. And begins to track. Other then that,
it works fine. Hopefully you can help me out. Thanks! Roger Schultz
Mike here: Have you done a CALIBRATE MOTOR and TRAIN DRIVES?


You know, as a matter of fact. I did a hyper tune on the mount. And I
have not done a calibration, or a drive training as of yet. Do you think
that could be the problem?  I was in such a hurry, to start using it. I
forgot about the initial start-up procedures. Another thing I did, was
go from an AR6, to an SN8. I changed the telescope type in the menu. But
that is all I have done.  Thanks alot! Roger
Mike here: CALIBRATE MOTOR adjusts for the power output of the encoders. So whenever the power source is changed (replacing batteries or changing to/from external power source) a CALIBRATE MOTOR should done. TRAIN DRIVES tells the AutoStar how to control the mount for a given angular movement. Both are important to proper operation of the AutoStar system.


Thanks very much for the info. I will perform the operations. And will
let you know if this solved the problem. CLEAR SKIES!! Roger Schultz

Subject:	OTA upgrade suggestions for Meade N6 LXD75?
Sent:	Sunday, April 20, 2008 03:08:25
From:	Craig Starnes (cstarnes@jcsautomation.com)
First, thanks for a fantastic site. I've spent a lot of time there over
the last year while modifying and learning to use my N6 LXD75.

I was wondering if you could give me some advice. I'd like to upgrade to
a bigger OTA, but keep my existing mount. My main reason for wanting to
do this is to improve my DSO experience; the 6" is a nice scope, but
just doesn't quite cut it when looking at the warm fuzzies. Of course
like most people, I also want it to be "ideal" for every other kind of
viewing also :D.

The problem is, I can't seem to find anyone that sells just the OTA...
much less ones that I know would be compatable with the LXD75. I'm
thinking of something along the lines of the SN-8, with the better
coatings and of course the extra 2" of aperature. I'd also like the
option of an electronic focuser that can be driven from Autostar. (I
heavily modified and installed one on my N-6, but it isn't ideal).

I basically just move the assembled scope from an upstairs room out onto
my deck, but I probably wouldn't want to go much bigger than an 8",
unless I can find something lightweight enough for the LXD75 mount with
better performance, and at a "reasonable" cost. I'm hoping to spend less
than $600 on just the tube.

Any advice?
Thanks again for the site and any help!
Craig Starnes
OKC, Ok.
Mike here: You might want to consider the 8" Schmidt-Cassegrain OTA. Even if you can't get the LXD75 model OTA with the pre-attached dovetail adapter you could get rings and a dovetail adapter that will fit the standard Vixen-style dovetail on the LXD GEM head. I suggest the 8"SC due to its longer focal length. I don't think you would see much difference in the N6 vs a SN8 given their similar focal lengths.


Where can I pick up these OTA's and associated hardware? I'm having a
hard time finding anyone that specializes (or even mentions) mixing and
matching tubes and mounts. Seems that everyone is just selling complete

Also, what will the longer focal length of the SC give me, vs. the 6"/8"
newt or SN? I'm still learning and trying to figure out the details when
it comes to focal length, etc.  :-)
Thanks again!
Mike here: Losmandy and ScopeStuff have rings and dovetails. Links on the Astronomy Links page on my ETX Site. Longer focal length means higher magnification. If you are unsure how to calculate magnification see the FAQ page on my ETX Site.


Looks like I may be sticking with my 6" for a while and just trying to
tweak it to it's best due to $$$, and there doesn't seem to be many used
larger tubes around.

As for the mount, I was reading this article on your site:


It mentions changing out the polar scope's allen head collimation screws
with thumb-style screws, which is a great idea based on my experiences
in trying to collimate the thing. Do you know what size screws these are
and where I could find thumb-style replacements?

I'd also like to replace my modified electric stock focuser (article is
here: http://www.sightsabove.com/article.php?article=13) with a higher
quality electric one that will still plug into Autostar. (I really like
having everything on one controller & the remote capability, but the
image shift with the cheap stock focuser is driving me nuts). Are there
any other options for this, other than the 1240 mod? Or how about a
higher quality focuser that can be modified with the 1240 or other Meade
Autostar complient electric focusers?
Thanks as always,
Mike here: Since my LXD75 was stolen last December I can't measure the screws. As to electric focusers, check JMI (link on the Astronomy Links page on my ETX Site). But theirs do not use the AutoStar.
Subject:	LXD55 & Meade 909 APM
Sent:	Friday, April 11, 2008 14:40:16
From:	fjmraz@hotmail.com
Do you have a collection of any mail and tips regarding the use of
Meade's 909 APM ?
Mike here: I went to my ETX Site and did a search for "LXD 909 APM" and got several hits. Try that.


Thank you...Found what I was seeking.


Feedback Archives

Check the Feedback Archives for previous editions of the User Feedback pages.

Go to the LXD55/75 Home Page.

Copyright © 2008 Michael L. Weasner / mweasner@optcorp.com
Submittals Copyright ©2008 by the Submitter
URL = http://www.weasner.com/lxd/feedback/2008/apr08/feedback.html