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.

The Scope is Ready for Viewing…but
The scope is ready for viewing the night
sky, sort of. As it stands, if the
telescope is currently in a good position
to view the night sky, so have at it by
pushing the buttons on the handset in
manual mode to aim the scope at the
Moon. Be aware that the scope won’t
follow the Moon if the “Tracking” isn’t
on.
Turning on the Telescope Tracking involves
trying to navigate through the AudioStar
Menu tree. Do yourself a favor and run off
a copy of the menu tree in the instruction
manual. Have it laminated or at least put
in a protective plastic sleeve. This is great
thing to have on hand and an easy
reference in order to quickly find the menu
item that will get you where you want to
go.
If the scope is really going to show you the
night sky it has to be first aligned with a
couple of prominent guide stars. With the
telescope system properly set up the
AudioStar Handset is going to want to go
through that alignment process. Read
about it, it is important.

Using The Technology Available
With the advent of cell phones, iPads, tablets and other handheld computers, backyard
astronomers have some powerful tools available to assist in the process of first identifying
what is viewable and where in the night sky it is located. During the Star Alignment process,
the AudioStar Handset is going to pick a couple of different stars that you as the observer
have to get centered in the field of view. The stars are going to be referred to by name and
that should be a clue as to the significance of those stars.
Well fear not, the techno geeks of the universe are here and they heard your anguished
cries for help. Apps such as “Star Chart”, “Night Sky Lite”, “SkyPortal”, “Sky Walk 2” and
many more are available for both the iOS and Android platforms. Some of the best ones are
free and most of them are very reasonably priced.
Just open an app, point the camera of the phone to the night sky and the phone’s screen is
filled with information as to what is currently visible and by zooming in, the constellations
with their major stars are drawn out and named. Comparing the image on the phone
screen to the real night sky can greatly assist you in getting your telescope aimed at the
correct star.

First Time Viewing the Night Sky
By this time you are itching to get going and don’t let anything stop you, but just a couple
more things for consideration. Have you read the menu tree of the AudioStar Handset? If
you haven’t made a copy of that menu tree you better have the instruction manual readily
available, you’re going to need it. There is options on top of options available on the
AudioStar Handset that you as the telescope operator have to choose from and one of the
first things to do is provide the handset with the time, date and zip code. This will be
important because AudioStar needs this information to tell you what is available for
viewing. It can be rather frustrating to try and figure all this stuff out, in the dark when
you really don’t have a plan.
Start off with the MOON. It’s big, it’s easy to find and most of the time it is so bright a
lunar filter should be screwed into to bottom of the eye piece to knock the brightness level
down a few notches. There plenty to see on the moon and the best time to view the
moon is when it isn’t completely full. There is a lot of detail on the “Terminator Line”
between light & dark and many astronomers favor this. Also, there is this thing called
“Beginner’s Luck” where you might see something on the moon’s surface that many
astronomers never see. A couple of those special things are the “Lunar X & the Lunar V.”
The is a couple of major named craters on the moon’s surface that when the light strikes
them at a certain angle a lighted “X” and a “V” are clearly visible. You never know,
sometimes it’s better to be lucky than good.

First Time Viewing Tips
Don’t try and take it all in at once, the universe has been around for awhile and by all
accounts, it is predicted to be around for a while longer. To that end, a couple of
convenient tools to have are a 2-Sided Planisphere, a Headlamp, and a walking stick.
A Planisphere is a tool that will show you, the
observer, to see what is available for viewing at
your location when adjusted for the correct day
and time of the year. It’s a handheld device and
will be found in many a backyard astronomer’s
tool kit. The headlight is great to have strapped
to your head and can be switched to a red light
so as not to ruin your light vision
The Planisphere can be ordered online and sometimes comes as an add-on with certain
astronomy books and instructional videos. The headlamps are available at Costco and
other retailers and the 3/pack shown was less than $20. You can get a good “hiking or
walking” stick at an outdoors shop. At times when looking through the eye piece you
have to steady yourself and you reach out and touch the scope. This causes vibration and
the object you trying to observe bounces all over the viewing area. A good stick or cane
to lean on will take care of that.

You’ve Seen The Moon, Now What?
The orbiting mud ball that we inhabit, is the “Third Rock From The Sun” called planet
“Earth.” There are several more planets in the solar system that are easily visible using the
ETX telescope. The AudioStar handset will have them on the menu as long as you
programmed in the proper information on start up.
Saturn is one of those planets where every person that has viewed it through a telescope
will remember when and where they were when they did it.
Jupiter is the big bully of the solar system and many times it’s moons can be visible with
just the use of binoculars. With a decent telescope, Jupiter becomes even more
impressive.
Mars, is the so called “Red Planet.” Take a look at it, you got to, you might even be the first
person to see the invading space force headed in our direction.
Other planets might also be visible depending on the time of year.

You Saw What You Saw But It Might
Not Be What You Expected Or Wanted
You took a look through your scope and you didn’t see images reminiscent of those taken
by some of the Deep Space Telescopes that are currently orbiting our planet Earth. Would
you care to think of the amount of money that was invested in those telescopes and what it
cost to build some of the earth bound telescopes housed in observatories peppered about
the globe? Put that into perspective when figuring in the cost of the telescope you are
currently viewing with and the images obtained.
Sometimes conditions in the atmosphere surrounding our planet fuzz out an image and
nothing viewed through the eye piece is wire sharp. That is why you should view things for
a period of time because conditions are constantly changing and from one minute to the
next can be quite dramatic. A good rule of thumb is when the stars aren’t “twinkling” that
is the best time to observe because the atmosphere is clear and not bouncing the light
around.
Don’t get discouraged, it takes a few times to get that “ah-ha” moment and many times
you just don’t know what you are looking at or if the scope is actually pointed in the right
place. A little research can go a long ways and maybe it might be a wise idea to “buddy up”
with somebody that does know what they are doing. Ya gotta do what ya gotta do to
smooth out the learning curve. Besides, the instruction book says you can always get a
bigger and more powerful scope if you’re not satisfied with the results from the ETX.

Couple Things You Might Have Done
That You Don’t Want To Do Again
•You shortened the length of the tripod legs so you could see through the eye piece when
the telescope was completely horizontal. Then when the scope “slewed” around (that is
fancy astronomer telescope talk to say the scope was moving side to side and up/down)
the eye piece was so low you had to stoop down in order to look through it. That is part
of the figuring out how to set up your own scope to fit you.
•Hopefully you didn’t rest anything in the space between the mounting forks underneath
the telescope’s Optical Tube. That space is a “Do Not Enter, No Trespassing Zone.” You
might have noticed that when the scope as aimed at something nearly straight up in the
sky there is hardly any clearance between the scope and the bottom of the mount. There
is a clear potential to cause damage to the Slewing & Motor gears if things get jammed in
that space.
•Did you put your hand on the scope or tripod when looking through the Eye Piece?
Notice all the vibration and that the subject matter of your viewing interest was bouncing
all over the place? You have to keep your hands off the equipment if you want a steady
image. The only time you want to be looking through the Eye Piece and touching the
scope is when you are adjusting the focus knob.

Astronomy Terms To Learn In Order To
Talk Like You Actually Know Something
•Slew: This is what the scope is doing when it moves up/down and side to side.
•Alt/Az Mount: Short for Altitude / Azimuth. Altitude pretty means what it suggests, how
high in degrees the scope is pointed in the sky. Azimuth refers to the degree the scope is
pointed from side to side. By default the mounting system on the tripod is an Alt/Az mount
but it can be set to be an
•Equatorial Mount: There is really no reason to use this feature unless you plan on hanging
a camera off the back of the scope. The tripod will be oriented so the Latitude adjustment
bar is facing to the front. The tripod base has to be raised and set to match the Global
Latitude of the Telescope’s current location. Then a “Polar Alignment” must be used when
setting up the scope for viewing. That is another can of worms best explained in the back
of the Instruction Manual. If you want to set your scope as such, then you must have
advanced knowledge and most likely know what you are doing. With a raised Equatorial
mount, the scope will now have enough room to Slew up & down without binding up
between the mounting forks.
•Polar Alignment: The scope is aligned so the North Star is positioned in the center of the
scope when viewing through the Eye Piece. That will be the scope’s home position.
•2 Star Alignment: The AudioStar Handset Computer picks two stars that have to be image
centered and then it is calibrated or “Aligned.” From there, AudioStar knows where
everything is in the night sky and can “GoTo” it with a fair degree of accuracy.

More Terms
•Magnitude: This is a term to describe the brightness of a star or object in the night sky.
The smaller the number the brighter the object is. Some guy in the far flung distant past
coined the term and the differences from one number to the next. The system has
undergone some changes but it is still in use. It is something interesting to look up if one
wants to know some background on some of the founding principles of Astronomy.
•Focal Length: Generally expressed, focal length is the distance (given in millimeters)
between the telescope's primary lens or mirror and the point where the light rays come
together in focus. Why is this important? Focal length is the major determining factor of
any given telescope's magnifying power.
•Objective Lens Size: In a telescope the objective is the lens at the front end of a
refractor or the image-forming primary mirror of a reflecting or catadioptric telescope. A
telescope's light-gathering power and angular resolution are both directly related to the
diameter (or "aperture") of its objective lens or mirror.
•Telescope F-Stop: The f-stop, f-number, is the lens speed of the telescope. It is the result
of dividing the focal length of the lens with the aperture of the eyepiece. The wider the
aperture, the more light it lets through, and the lower the f-stop number. A telescope
with a short f ratio (usually f4 or f5) is considered a rich field telescope and is suited for
viewing the skies in wide views such as constellations, nebulae, clusters and other rich,
scattered items. A telescope with a medium f ratio (usually f6 to f8) is considered a good
all purpose telescope f ratio.

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DARKSIDE