Meade ETX-90 User manual

The Meade ETX Telescope
A Tutorial for both Basic and
Advanced Setup

A Service Provided by the

The Meade ETX 90
The Meade ETX series is a sophisticated entry level
telescope suitable for people that would like to view
the night sky without spending a huge amount of
money. They actually have many of the features found
in more of the higher priced & more advanced
telescopes available. The biggest difference is the size
of the Optical Tube Assembly (OTA) and its ability of
gather light from the darkness of the night sky.
Although this telescope is deemed as an entry level
scope it is still a precision instrument in its own right. It
comes with an instruction manual that can be very
frustrating to understand by a person just starting out.
Once there is an understanding of what the manual is
trying to convey, that knowledge is very useful to the
person that is of a mind to upgrade their telescope
system to a more powerful light gathering model

First Step
Make an honest attempt to read and understand the
manual and have the scope and its various parts on
hand while doing so. Don’t be in a rush to set the scope
up and expect to see “Hubble Space Telescope” images
after your first observation session. The ETX is a long
way away from the “Hubble”. The ETX is great for
viewing the moon and many of the various planets in
our solar system. Most of the “Deep Sky Objects” such
as Nebulas and distant Galaxies that might be nothing
more than a smudge in the night sky when viewed with
the naked eye, will be just a more defined smudge when
viewed through the ETX. Reading the manual at least
two to three times is a good idea.

Once becoming totally confused after reading the manual you will most likely just
want to set the scope up and get with the program so let’s do it.
The tripod should come with its
own duffle bag and it can be a
struggle to extract the tripod and
later put it back in.
The Instruction manual is actually pretty clear on how to
set the tripod up but there is one tip to keep in mind.
Don’t extend the legs all the way out, leave a little bit of
length for leveling adjustment later. With the legs fully
extended a person sometimes has to adjust two legs
whereas if there was some length left, adjusting one leg
would do the trick. Adjusting the height of the tripod is
an exercise in “trial & error” and the correct height will
only be settled on after several observation sessions and
each adjustment messes with the level of the scope.

While setting up your tripod, line up the Latitude
adjustment rod of tripod’s mounting plate to the
back and the forward leg to either “True North” or
”Magnetic” North. This will come in handy when
you have to align the telescope with a couple of
“alignment stars” later. Also get the top mounting
plate as level as possible by adjusting the length of
the tripod’s legs. A useful tool in performing these
operations is one’s cell phone using the compass
function and a free “level app”.
Another thing to note is that after mounting the telescope to the tripod as shown in the
instruction manual, it might be necessary to lift the entire telescope/tripod assembly in
order to get the telescope pointed in the direction of either “True North” or “Magnetic
North” after setting the scope to its “Home Position”. The operation of leveling the
scope might have to be repeated and the adjustments should be very minor.
(There is no real Front or Back on the Telescope but on the bottom of the Telescope base
there should three small rubber pads. Assemble the scope so the two pads are in the
back with the single pad facing forward. The control panel at the base of the scope
should be on the left side. Orienting the scope in this way will provide for full range of
motion when the telescope “Slews” to a selected target in the Night Sky. This is called the
default “Alt/Az” mount)

Mount the Telescope to the Tripod
The instruction manual shows in very good detail how to mount the scope to the tripod.
For the most part there is no reason to concern yourself with what the latitude control
arm and latch does. All you want to do is loosen the latch, raise the attached plate to
expose the knobs of the telescope attachment screws. Follow the directions to get the
scope securely fastened to the tripod mounting plate. Push the plate down all the way
and tighten the latch. At this point, take the dust cover off the eye piece holder and
replace it with an eye piece. Tighten the set screw to secure the eye piece in the holder.
Aligning the Finder Scope with the Optical Tube
This is an important step. Getting this done right will greatly increase one’s chances for
success when trying to locate something in the night sky. All of the next several set up
operations should be done outside in the daylight hours. Pick something out in the
distance no closer than 200 yards, preferably farther. Remove the dust cover from the
front of the optical tube, loosen the horizontal latch at the base of the scope while
loosening the vertical knob on the right fork of the scope. Loosen these to the point
where scope can be easily turned side to side & up and down with a small amount of
resistance.

Finder Scope Optical Tube Alignment (continued)
Some models of the ETX, depending on date of
manufacture, have different Finder Scopes. Some
have an electronic red dot and others might have a
low power scope with crosshairs, mounted to the
main telescope body.
Use the Finder Scope to aim the main Optical Tube at the intended target in the distance
and then look through the Telescope Eye Piece. Most likely you are going to have to turn
the focus knob on the scope in order to see anything at all. Also, when viewing through
the eye piece, the image is backwards, so up is down, down is up, right is left and left is
right. Make whatever adjustments are necessary to get the intended target in the viewing
center of the Eye Piece. Take your time, this backwards way of looking at things is the
same in most if not all telescopes available to the backyard astronomer. This image can be
“corrected” if a person wants to spend some money and if something might actually be
available to do so, just get use to it.
Once the target is centered in the main telescope, lock down both the horizontal and
vertical adjustments. Now adjust the Finder Scope so its center of target matches that of
the main Telescope. Now both the main scope and spotting scope should be aligned. In
the future, the Finder Scope, with its wider field of view will greatly assist in the search
and finding the selected targeted objects for night sky viewing.

Put the Telescope into its Home
Position
With the alignment of the spotting scope
and main Optical Tube complete, get the
scope set up in its “Home Position” for the
operation of “Training the Drive.”
Loosen the “horizontal” lever at the base
of the scope and turn the scope counter
clockwise until it comes to a stop. Now
turn the scope clockwise until one of the
fork mounts lines up with the power
controls on the scope base. Lock down the
horizontal lever. Replace the eye piece
with the combination bubble
level/compass that is included is the
telescope package. If that is missing, put
your cell phone on top of the eye piece
holder and use the compass and level
apps. If necessary lift the entire assembly
to achieve “True or Magnetic North”
alignment of the optical tube.
Loosen the vertical lock knob on the right
fork of the telescope to adjust the optical
tube with the use of the bubble level or cell
phone app. You might have to adjust the
tripod legs in order to center the bubble in
the level. With some practice, this
operation becomes much easier.

Training the Drive
It is assumed that batteries have been installed into the telescope or that the scope is being
supplied with power from some source. If that is not the case, disassemble the scope from
the tripod and install the batteries. After reassembly, don’t worry about any alignment
issues with the spotting scope, that is taken care of. The scope should still be pretty level,
just do a quick check to confirm and move on.
In the back of the Instruction Manual is a section called “Training the Drive.” You are are
going to power up the scope and use the “AudioStar Handset.” (The Instruction Manual
might refer to the Handset as the “AutoStar Handset.” It is “Audio” because when you select
an object a voice from the Handset will describe the object in detail.) Read the directions
first before doing anything. Sometimes there is a thing where the “cart gets before the
horse.” If you read the directions first there is less of a chance of that happening.
What Training the Drive does is help with aiming issues so the scope returns accurately from
one celestial object to another. The AudioStar Handset is a small computer that controls all
the scope’s movements. Pick something displayed on the handset menu, press the “GoTo”
button and the scope moves to point directly to that object. A step in getting the scope to
move and accurately settle in on the desired object is to “calibrate” it so all the movements
are repeatable. That is what “Training the Drive” does. This only has to be done very
infrequently or if there is a decided lack of accuracy in where the scope is pointing.