Last updated: 31 August 2006

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:	updating LXD75 autostar controller
Sent:	Tuesday, August 29, 2006 23:45:06
From:	Todd (scopehead@cox.net)
I found your site by searching the web. I was updating my LXD75 hand
controller tonight and something went wrong.

My PC locked up after waiting an hour or more. I restarted. it seems the
controller was not able to finish updating. now when I turn on the scope
I get nothing! did I ruin the controller for good? thanks for the help.


I did not realize you work at opt I buy all my astro stuff there! I will
have to look you up next time I am there.
Todd Rogelstad
Mike here: You can restore the AutoStar by putting it into SAFE LOAD mode; hold down the ENTER and SCROLLDOWN keys (opposite "corners" of the AutoStar) and then power on the telescope. You should see something like "FLASH LOAD READY". Launch the Autostar Update application and it will detect that mode and let you reinstall the ROM. You will have to re-select your Site info and do a CALIBRATE MOTOR and TRAIN DRIVES again. I don't WORK at OPT; I just do some things with them.


THANK YOU!!!!!!!!!!!

Subject:	Of LXD-55 EMC problems
Sent:	Sunday, August 27, 2006 03:20:59
From:	martin dawson (flugluftholgate@hotmail.co.uk)
I know you are on your travels, hense short email, but I have a question
for every one and not sure where to post it...

Early 2006 two incidents alerted me to a potential problem while at a
star party my LXD-55 5-in refractor started erraticly slewing whne I
thought I had cured the problem, within is seconds of it slewing some
one nearby had a mobile phone go off, is there a link? EMC problem

Has any one noticed this before???

Looking back I must say most of my problems have been when I was in a
group and hardly ever happend when observing on my own....

Regards and best wishes to all
Martin Dawson
ex-York AS
Mike here: Don't recall any cell phone EMC problem ever mentioned but have you checked your battery level, done a CALIBRATE MOTOR and TRAIN DRIVES? Also, if you have an Autostar cord with a ferrite core at one end, I've found that if I place the core next to the Autostar I get "random slews" but with it next to the LXD base, no problems.


thank you for your reply, done all that, you suggested those ideas a
while ago (graphit core at the LXD end and not handset...) , i now drive
my telescope off a brand new 12 v moped battery, works a treat, then
these two phone went off, i had a suspiction some 18 months before, but
the crowd was big and it was dark so i could not see any one on a phone,
but I am sure I heard a ring-tone. I'll have to do some more work on my
idea. I would be interested in other poeples ideas and experiances.
Regards and bests
Martin dawson
Mike here: I've had my Verizon digital phone on while next to the Autostar and have even used it while at the eyepiece (describing to a friend what I was seeing as I observed a triple Jovian moon transit my 8"SC). No problems with that particular phone.
Subject:	Re: Fixing a Slipped Right Ascension Gear
Sent:	Tuesday, August 22, 2006 06:11:46
From:	Patrick Doyle (pdoyle4749@eircom.net)
In your techtip on the above you state the following for removing the
small set screw in the RA gear which had slipped:

"I removed the small setscrew in the silver gear using a 2/32" hex key
and slid the gear along the shaft to expose the flat side of the shaft."

I interpreted 2/32" as 1/16" so I bought a 1/16" hex key.  It was far
too big.  I took the gear wheel with the set screw to my local
specialist tool supplier and tried several keys before finding one that
fit.  It was a tiny key, 0.050" (1/20").

Using that key I completed the repair and my RA drive is now working.

I hope this is helpful.

Best regards,

Patrick Doyle

Subject:	LXD55 Astrophotography 
Sent:	Monday, August 21, 2006 10:38:36
From:	Steve (bullfox@comcast.net)
A few days ago, after several years on inactivity, I unpacked my LXD SC8
and took it to one of the better dark sites in the SF Bay Area.  It
rates about 4 on the Bortle dark sky scale. I had a wonderful evening. 
It was shirt sleeve weather until almost midnight, the milky way was
quite prominent, and M13 was ghostly scintillating, almost glittering. 
I say the ring nebula for the first time.  It was like a little iced
donut in the sky (I probably should have brought more to eat),  .

Anyway, the mount performed extremely well.  Although I have never had
much luck with the go to stuff,  the mount traced well, keeping M13 in
the field for about 5 minutes at 68x.  I have the hypertune kit, but
have never done it.

My question is this.  Given my level of slothfulness and experience, and
for the same site, what would you recommend for deep sky
astrophotography?  Meade and Orion both have astrophotography systems
for about $400 to $500.  Would you recommend either in my case?
Mike here: If your choice is between a Meade DSI model and an Orion model, I would go with the Meade one for two reasons: integration with the Autostar and the image processing software that comes with the DSI. Keep in mind that you need a computer with a RS-232 port and USB 2.0. If you only have USB you will need a USB-serial adapter; not all the adapters work reliably so see the article "Autostar and USB" on the Autostar Info page on my Site.


Thanks for the prompt reply and recommendation.  There is also a very
complementary review of the Meade DSI in the September issue of Sky and
Telescope, so I think that is what I will get. I have a pretty decent
laptop, so I am set up computerwise.  I got out the hyper tune kit and
cd to review.  I think I am getting some slippage on one of the axis so
I will have to go ahead with that project.

Subject:	Fixing a Slipped Right Ascension Gear
Sent:	Wednesday, August 16, 2006 10:32:08
From:	Patrick Doyle (pdoyle4749@eircom.net)
Exactly this problem occurred on a mount that I purchased second-hand
via the internet. The seller said it worked perfectly before he sent it.
When I checked it out it worked in Dec but not in R.A.  I even removed
the wrong screws as in your description.  I still have to find some hex
key in inches.  All mine are metric.

I am extremely grateful for the help I got from your technical tip on
this problem.
Patrick Doyle

Subject:	altering the lxd75 tripod
Sent:	Saturday, August 12, 2006 08:50:47
From:	roger schultz (rdschultz4201@sbcglobal.net)
Hello, My name is Roger Schultz, I was reading one of your articles,
about the lxd75 system. And somewhere in there, was a reference to
making the tripod longer. in concern with using the refractor type
scopes. If you could steer me to the right area, it would really help.
Thank you very much!
Mike here: I don't recall the specific reference. Could you be more specific as to what you want to do.


What ever the article was about, They were discussing the fact of it
being hard to bend over so far all the time, to observe thru the
refractors. Because the lxd tripods were so short. They said that there
was a way to extend the tripods to make them longer, but that topic was
discussed in another part of the article. The writer of the article, was
a guy named mark. Hope this helps, If not thanks anyway.
Mike here: I did a search for all articles on the LXD site with "LXD75 refractor mark" and nothing suitable turned up. Perhaps someone will respond.
Subject:	Old Link for Collimation
Sent:	Friday, August 11, 2006 13:27:02
From:	Wayne Watson (sierra_mtnview@earthlink.net)
I found this one one of your pages, but the link does not have the pdf.

From:	George [cross-posted from the LXD55telescopes Yahoo Group]
For those of you who wish to try collimating your AR 5 or 6" refractor.
There is a web site that offers a pdf for you to download. It's by
"Synta" a Chinese telescope manufacturer that makes scopes for
"Celestron" among others. The url is:

         Wayne T. Watson (Watson Adventures, Prop., Nevada City, CA)
Mike here: Thanks for the report. I'll remove the item.


I sure wish I had the reference. I need it for the LXD55 I'm working on.
I had to remove all six screws on the collar around the 6" objective,
and want to make sure I get it all back properly. I did find a 10 page
pdf, but it hardly addressed the push-pull mechanism. It did discuss
just about every other type of adjustment.
Mike here: Just one of the problems with the Web. Things come and unfortunately, sometimes they go.


Yep. However, there's some facility out there that records it all. Hard
to believe, and, of course, I don't expect you to fetch it from the deep
archive. :-) I'll plumb the lxd55 YG.
Mike here: That would be the Wayback Machine. Link at www.archive.org.
Subject:	Parts for the LXD 75
Sent:	Tuesday, August 1, 2006 00:01:28
From:	David Duffy MEd. (dduffy2@satx.rr.com)
I was wondering if you knew of/ had a favorite place to buy replacement
parts for the LXD75 mount. My Dec motor has just started going around
and around without stopping. I took off the cover and watched it and
noticed the little LED by the slotted wheel doesn't appear to have any
light coming out of it. Should I be able to see light in a darkened
room? Have you run into a problem with a non-stopping Dec control and
finally... where could I get parts (maybe a whole new dec motor) to try
to fix this?

Thanks much

Dave Duffy - San Antonio Tx
Mike here: If the mount is still under warranty, contact Meade. Otherwise, you can try Telescope Warehouse (link on the Astronomy Links page on my ETX Site). Have you done a CALIBRATE MOTOR and TRAIN DRIVES to see if that resolves the problem? As to light, never looked myself and since I'm on vacation I can't check.


No, no, no; I'm sorry I bothered you on vacation. I know what that's
like. I have another question (feel free to wait to answer after your

Are the two gears (that are accessible through the little plastic doors
on the side of the housing) supposed to be lubed with anything? I looked
in the manual and it says nothing about maintenance for the mount.

By the way I looked at the Telescope Warehouses listing and they had no
parts for an LXD75. Thanks anyway.

And I did train and calibrate. That all seems to go ok. But when I try
to align the scope the Dec axis just keeps turning and turning. It's
like the Autostar is getting no feedback from the motor. I tried two
different Autostars by the way. (I have an ETX-105 also.) Same result.

Well, thanks for your help, I hope you have a great vacation. And I look
forward to hearing from you.

Dave Duffy
Mike here: There is some lubrication visible (at least there was on my LXD55 mount; I'm hundreds of miles away from my LXD75 mount so can't check it). Have you checked the setscrews on the gears?


Thanks anyway Mike, I've decided to send it to Meade. Apparently they'll
fix anything for $75. So I'll let them do the work.


Subject:	piggybacking an AR5 on LXD 75  8" SN
Sent:	Thursday, July 27, 2006 18:59:35
From:	Harold Ogden (hlogden31@msn.com)
would piggybacking an AR5 on to my LXD75  8" SN be to much weight? My
other choice would be picking up a LXD 55 tripod and head for the AR5. I
have seen them listed for under $300  Thanks Harold
Mike here: I suspect that the AR5 would be too much weight. I have piggybacked my ETX-90 OTA and Nikon D70 DSLR on my LXD55 (and now LXD75) 8"SC and that seems just at the edge.


I have one more question is the LXD 55 tripod adequate for the AR5
(15lbs) or should I go for a LXD 75  Harold
Mike here: The LXD55 originally was used for the AR5 so it should be no problem from that standpoint. However, the LXD75 is a nicer mount. You can see my comments on the LXD75 mount on the LXD Site.
Subject:	lxd75 polar scope alignment
Sent:	Wednesday, July 26, 2006 17:51:10
From:	roger schultz (rdschultz4201@sbcglobal.net)
Hello, I would like to know if I could get a few tips on aligning my
polar scope to the R.A. axis. I tried marks procedure. And spent an hour
in the driveway, sweating, and swearing. It seemed the more I tried to
adjust it, The worse it became. Is there a secret to adjusting these
screws? They are very touchy. I could use any help that you could give
me. Thank alot! Roger Schultz.
Mike here: Check the article "Using the Polar Alignment Scope" under the LXD55/LXD75 Information section.


Yea, I found that article after I wrote you. I was doing it completely
wrong. Thanks for getting back with me! You have a very in depth web
site. I have found so many things, on your web site. It has really
helped me gain alot of knowledge about my AR6. I just purchased this
scope, and theres alot of things that the manual doesn't cover. I was
having trouble with the dec. axis, taking to long to react to the
buttons. I found the info on your site. And the problem is now solved.
Thanks for being there! Roger Schultz.

Subject:	kocab clock polar alignment method lxd75 mount
Sent:	Monday, July 24, 2006 12:20:40
From:	roger schultz (rdschultz4201@sbcglobal.net)
Read Marks method of polar alignment. Tried it out last night. It really
works great. I did not try tracking, but observed image in crosshair
retical for long period. the drift was minimal. I am going to make sure
my polar scope is well aligned, and try it again. But for using this
method one time, I really noticed the difference in my ar6 tracking.
Thanks for the suggestion Mark!

Subject:	LXD 75 mount tracking intermitent and goto 's the same.
Sent:	Saturday, July 15, 2006 21:53:28
From:	Greg Kaiser (kizrus@phreego.com)
Didn't know if you got this one on the group so I thought I'd forward it
to you since I know you said you were going to purcahase an LXD75 mount
back a month or 2. If you haven't removed your motors and looked and all
4 gear mounts to their shafts then you should.

All 4 gears on mine had only one set screw the smallest one in loose
againsts the shaft flat. The other 4 3/32 were missing. I went to ACE
hardware and got 4 to fill the empty holes and will place them on the
shaft flat and use the secondary smaller ones as a backup on the round
of the shaft. I was told also to check the encoder allens but not much
stress on it however but to bend it could be a problem. I'm using the
Blue as a backup.

Let me know what you find? My friend bought his from Starizona and
bought mine from telescopes.com. He found his first but at the time I
wasn't having the issue and had checked and they were tight then. So
much for assembly quality.

Mike here: Won't have a chance to do that until I return from my 3 week vacation. But so far, I've had no problems with the LXD75 mount, as noted on my "My LXD75-8"SC Experiences" on my LXD55/75 Site.
Subject:	re: lxd75 drive training
Sent:	Saturday, July 15, 2006 18:51:27
From:	richard seymour (rseymour@wolfenet.com)
From the symptoms, i would suspect that one of your
transfer gears is slipping on its shaft (they are
supposed to be secured by a small set-screw).

Open the inspection ports (or remove the covers)
and look at the final two gears before the worm.

If they are loose, gently tighten them
If there is a "flat spot" on their shaft,
try to have the set screw be centered on that flat.

good luck
Mike here: Thanks Dick. I wouldn't have suspected that since astronomical GOTOs seemed OK.


I've closed the browser... i thought he said they were "poor".
Whatever... slipping gears and goo on the encoders can cause this.
Opening and -looking- beats theoretical any old day...

have fun


Alessandro Odazio wrote:
> Thank you for your support, Dick.
> Yes my astronomical GOTOs are poor .
> I've looked carefully (removing the gear box by turning a hidden hex 
> bolt in the GEM head) to the transfer gears and they are not slipping.
> I've also tried further tests: I made a  reset-calibrate-train session 
> once more on Polaris, last night, and then switched off the
> Autostar. Then I've removed the OTA from the mount, unlocked the Dec. 
> and RA axes, switched on the
> Autostar again, selected "terrestrial" and pressed "mode" to show RA and 
> Dec values. Same problem: RA values encrease every 2 or 3 seconds
> (i.e. 17:09.8, then 17:09.9 and so on...).

Ummm... they should.   If the mount is -not- tracking the stars
(and "Terrestrial" turns that off), then the RA "in front of the scope"
*will* increase one RA second per clock second.   (or one tenth RA minute
per clock 6 seconds)

> Then I've  assembled the telescope on the mount, aligned to Polaris and 
> then I've made a three star alignment (Arcturus, Mergrez and Vega).
> GOTO on Arcturus: about 5 degrees off. I've centered it in a reticle 
> eyepiece and then made a SYNC. Then GOTO on Polaris: the telescope has
> pointed somewhere in Pegasus, many many degrees off.
> So, I've made another three star alignment (same stars) and then a GOTO 
> on M31: about 5 degrees off.
> Another GOTO on Polaris and the telescope pointed somewhere in Bootes.

Open the motor case again, and inspect the encoder disk for dirt and
grease.  Be gentle to it (very fragile).  Test that -it- is not slipping
on the shaft.
The fact that your error is -repeatable- (5 degrees off each time)
suggests that you might be aligning on at least one wrong star.

Try a One Star align.

Some versions of the firmware PARK the scope in the wrong position
(90 degrees rotated to what the manual specifies).  Use the manual's
starting position.

Do not attempt to operate the scope (for accuracy, versus "just looking")
with the covers open... the encoder sensors see the outside lighting.
Also check that the encoder LEDs and sensors are *centered* on the
slotted portion of the disk, and not off to one side.

good luck


Richard Seymour wrote:

>Open the motor case again, and inspect the encoder disk for dirt and
>grease.  Be gentle to it (very fragile).  Test that -it- is not
>slipping on the shaft.
>The fact that your error is -repeatable- (5 degrees off each time)
>suggests that you might be aligning on at least one wrong star.

I guess the problem has been found: the encoder disk was slightly
slipping on the shaft and I've tried to fix it with a small drop of
glue. I'm doing another observing (and test) session, this evening, and
I will let you know any news (but the terrestrial GOTO is now almost

Many thanks to all of you, Mike and Dick, for your kind support.

And an update:

Dear Mike and Richard,
after having fixed the slipping encoder wheel, my GOTOs have been
excellent , last night.
Many thanks again for all of your support and time.

Subject:	lxd75 drive training
Sent:	Saturday, July 15, 2006 02:19:49
From:	Alessandro Odazio (alexconte@alice.it)
I'm having troubles when training drives on an LXD75 SC8". I do a reset,
calibrate motors, train drives using a reticle eyepiece.

When done training I select "terrestrial" from "targets" in Autostar,
aim to a terrestrial object, set it as a landmark, move the scope using
the keypad and then try a goto to the landmark. The scope then moves
elsewhere, missing the landmark with a huge error (always different).

I've also noticed that, when in terrestrial "tracking" mode, if I select
a target, watch at the RA. values, then move the scope using the keypad
and then move the scope back to the target (I use a reticle eyepiece) I
always have different readings on the RA values.

I've also noticed that, when selecting "terrestrial", if I use the
"mode" key to print on the LCD the RA and Dec Values when the scope is
aiming to a landmark, the RA values increase constantly one time per
second. This does not happen when in "astrononical" tracking mode.

When using the scope on astronomical objects my goto's are quite poor
but the object selected is always in the FOV of the finder. Anyway the
tracking is pretty good, when the mount is properly polar aligned, and i
can keep an object in the center of a 12.5 mm reticle eyepiece for more
than 5 minutes without corrections.

Thinking of a problem with spurious light hitting the sensors, I've
trained on Polaris but nothing changed.

Any help would be appreciated.
Thanks in advance,
Mike here: Since the GOTOs and tracking are pretty good for astronomical objects, the problem seems to be in terrestrial mode only. Have you checked the balance of the telescope; it sounds like there could be some slippage when slewing. Have you tried the same tests with the mount in Alt/Az (you will have to remove the counterweight rod)?


Thank you for your prompt reply.

Yes, the telescope is properly balanced and I have the same problem with
the mount in Alt/Az.

I've just tried to reset-calibrate-train once more and then switched off
the Autostar. Then I've removed the OTA from the mount, unlocked the
Dec. and RA axes, switched on the Autostar again, selected terrestrial
and pressed "mode" to show RA and Dec values. Same problem: RA values
encrease once a second (i.e. 20:12.5, then 20:12.6 and so on...).

I've tried the same tests with different firmware versions (the latest
ROM version is now installed) but nothing changed ...
Mike here: Since I've never played with terrestrial on my LXD I don't know if that is normal or not and I can't check it as the mount is disassembled in the garage right now (from my last trip to Oracle Observatory) and I'm getting ready for my 3 week vacation.


Thank you for all of your support, Mike.
And clear skies for all of your vacation.

Subject:	LXD75SC. or Nexstar8I
Sent:	Friday, July 7, 2006 07:27:07
From:	Eric Sweitzer (esweitzer@seifert.com)
I am currently looking at buying an 8" S.C., I am considering the lxd75
S.C. or the Nexstar8i, I think the Meade looks better built, but all the
information I have read for aligning the Equatorial mount makes it seem
very difficult to do. How much more difficult of a process to align the
G.E.M than an ETX? Sometimes getting my etx125 aligned is a pain, that
is why I am also looking at the Nexstar8  with its Skyalign. Whether it
works as advertised is where I was hoping you could shed some light
between the pros and cons of these two scopes other than the weight.
Thank you for all of you help, Eric
Mike here: The LX90 8"SC is more comparable to the NexStar 8i as both are Alt/Az mounts. But aligning the GEM LXD75 mount is certainly no more difficult than aligning the ETX in Polar Mode. Where confusion typically arises with the GEM is how to swing it manually to point at objects. But that confusion is easily overcome with experience. Afterall, people have been using GEMs for a LONG time. I haven't experienced the NexStar alignment system so can't comment on it but reviews I've seen say it works just like the Autostar works; they both align and GOTO.
Subject:	Cleaning LXD55 SC-8 with UHTC
Sent:	Saturday, July 1, 2006 20:37:17
From:	Lamar McLouth (lmclouth@a1isp.net)
I see on your site a review of Dr. Clay's cleaning kit.  In it you
mention that you (at that time) had not had to clean your SC-8. Have you
had to yet?

I've had my SC-8 (with UHTC) for several years now and it appears to be
cleaned.  If the Dr. Clay's cleaning kit worked well for you, I would
like to give it a try.

Thanks for your input.

Mike here: Actually I did clean it using Dr. Clay's Cleaning Kit just before my last trip to Oracle Observatory. No problems.

Feedback Archives

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

Return to the top of this page.

Go to the LXD55/75 Home Page.

Copyright © 2006 Michael L. Weasner / mweasner@optcorp.com
Submittals Copyright ©2006 by the Submitter
URL = http://www.weasner.com/lxd/feedback/2006/aug06/feedback.html