Last updated: 14 July 2008

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Subject:	ETX125 on LXD75 mount
Sent:	Sunday, September 17, 2006 14:04:02
From:	spunkyk98 (
just thought I send you a pic of my ETX-125EC mounted on an LXD75 mount.
When funds become available, I plan on mounting a 8" OTA to the LXD75
mount.  For the time being, I put my ETX-125 on the mount.  I had to
modify one of the dove tail holes to match the mounting holes on the
bottom of the ETX125 OTA.

I bought the LXD75 mount used with a dove tail bracket, a autostar #497,
a battery pack and couple of weights. The mount tracks beautifully! It
can hold an image in a 26mm eyepiece for hours. I tested out my Nikon
D70 mounted to the top of the OTA and I got some nice pics but when I
zoom in on those pics, I can see I didn't have the camera well focused.
So I'll be doing some more D70 mounted pics in the future. I want to
test out using the D70 at prime focus as well.  Right now, the mount can
easily hold an image for more than 2 minutes for astro pics without star

I used a DSI-c connected the EXT125 and was amazed that I didn't have to
fight trying to keep the image centered in Envisage.

The only problem I really encountered was when I tried to train the
drives. The AZ/RA slewed the scope, but re-centered the object I was
training on. So I could not train on that axis. The ALT/DEC training
worked as I expected. Not really sure what's up with that. The tracking
is unbelievable as it is right now. But, I can't help to think I may
have something wrong with the setup. The scope is balanced on both axis.

Here's what the ETX-125 looks like mounted on an LXD75 mount:


I have seen some posts on your site regarding mounting an ETX125 OTA on
a LXD75 mount, so I thought I would post this.

Mike here: Did you do a CALIBRATE MOTOR?


Well, as a matter of fact, I loaded up the latest Autostar software and
patch43aa. Then did a RESET/CALIBRATE MOTORS/TRAIN DRIVES I think, but I
don't remember now with all the excitement of the new mount.

I'll will retry the drive training, and I want to go thru the LXD55/75
ADJUST training while we have cloudy weather here. As soon as I turn on
the telescope now, I usually do a CALIBRATE MOTORS because I'm usually
not sure if I last used the battery pack. So, hopefully that's what I
forgot to do the first time I turned on the Autostar after updating the

Thanks for the help, I'll let you know how it works out.

Subject:	Re: ETX125 on LXD75 mount update
Sent:	Sunday, October 8, 2006 21:19:55
From:	spunkyk98 (
LXD75 mount...

I did a RESET/CALIBRATE MOTORS/TRAIN DRIVES, during the RA training, the
scope slewed, but the target I used for training was very close to
center, and does this for both directions. For the DEC training, the
scope slews to just outside of the field of view for both directions
during training.

I took off the motor houses, and I noticed the DEC motor decoder wheel
was bent! The RA decoder appears to be just fine. Don't know how the
wheel gets bent, I haven't crashed the motors into the mount at all. I
did buy the mount used, so it could have already been bent. I used a
trick from, I colored the RA encoder wheel flat black on both
sides. The mount moves as smoothly in RA as it does in DEC. And the worm
gears turn smooth on both axis. I did another RESET/CALIBRATE
MOTORS/TRAIN DRIVES, the RA training was the same as I stated above. 
After the first alignment star, the goto's are almost perfect! The
tracking is still very good.

I noticed now with the battery pack connected and fresh batteries, the
RA motor tends to make a whinning when it's slewing like it's not
getting a constant rate of power. When the AC adapter is connected, it
is not as noticable. The DEC motor sounds fine on both batteries and AC
power. I'll probably just leave it for now, until I get a 8" OTA to
mount on it, and see how it performs.

Thanks for the help,

Start of today's update
Subject:	ETX on LXD Mount
Sent:	Thursday, July 10, 2008 22:55:17
From:	Peter Green (
I have been frustrated with the ETX mount and so in early 2005, I
entered into conversations with OPT and Parallax about how I might be
able to mount my ETX125 to an LXD mount.  My plans got some what delayed
when we decided to build a new house (away from city lights).  But
tonight I'm happy to report a successful outing with my new setup. 
Whew, took a while but was worth it.

I've been trying to keep up with the website to see if anyone else has
done this but I haven't seen any details so far so I hope this is
helpful.  Anyway, I purchased a Meade SN6.  I figured it was worth
having a short and long focal length scopes.  I worked with parallax on
a set of customized tube rings, but in the end we just used their
standard 6" rings with some extra felt to make a compression fitting to
keep the ETX scope snug.  The Parallax rings are mounted to a vixen
saddle plate and voila, I have a compatible setup to mount directly on
the LXD dovetail.  (picture is attached).

I did have some trouble with alignment at first.  I started by setting
the telescope in Autostar to ETX125, and mount to "polar".  I guess
Autostar must assume ETX125 means the Alt/AZ type mount, because when it
came to alignment I found Alt/AZ in polar mode does NOT equal a German
Equitorial.  When I first tried to align the scope, the mount was way
off in left field.  So, I changed the telescope to LXD/SN8, and I
changed the focal length to 1900.  I calibrated and trained the drives. 
Tonight I had a successful 2 star alignment after a few failed attempts.
 I did have to be a bit more precise in polar home position, and once I
did, the scope aligned OK.  I would also note that by selecting LXD/SN8
for the telescope gave me a different message at alignment-- it actually
used the phrase "German Equitorial" which it didn't before, so gave me a
good feeling I was on the right track.  A GOTO of Jupiter was OK,
although not perfectly centered.  However, I did a "tonights best" tour
and the scope performed great.  I saw many more of the Messier objects
than I ever have before.  This mount configuration was so very much
better than the ETX mount!  I did not experience any of the drift or
other mount issues.  I'm also confident I can easily mount a camera to
this mount and it will handle it without problems.  It was truely a
dream to use my ETX!  I will say that due to the short tube of the ETX,
I was only able to balance the scope around one axis.

I hope this helps anyone who is thinking about a different mount for
their ETX.  I would also ask for any advice from anyone regarding
alignment.  As I stated, I only achieved a successful alignment after a
fair amount of due diligence in polar alignment.  I may need to tweak my
settings in Autostar a bit.  I also have a question about when it comes
time to swap my SN6-- I assume if I have an autostar for each OTA (tube
settings, trained and calibrated) that I shouldn't have any problems
swapping between scopes?

Thanks for the great website, and I'll you updated on my progress. 
Based on first indications, this setup works awesome!

--Pete in Iowa


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