Orion StarMax 90 User manual

Library Edition TableTop Telescope
Instruction Manual
Orion StarMax 90 TableTop Maksutov-Cassigrain
Telescope
Based on the Orion TableTop Telescopes Instruction Manual
Donated b :
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Cautions
Do not point the telescope at the sun. Looking
at the Sun with this telescope can cause eye
damage and blindness.
Do not touch or attempt to clean the optics
(corrector plate and eyepiece). Some dust or
dirt will not affect the view. The optics can be
damaged by improper cleaning. Return the
telescope to the library for cleaning.
The Telescope
The tabletop telescope will provide stunning
views of the Moon, planets, and the brighter star
clusters and nebulae. The telescope will produce
right side up terrestrial images, however they will
be mirror images, as will the celestial images.
Telescope parts (see
illustrations 1 & 2)
Zoom eyepiece: Focal length is adjustable from
from 2 mm (60X) to 7 mm ( 80X). The
eyepiece has a rubber eye cup than can be folded
down for eyeglass wearers.
Optical tube: Contains the primary optical
components: A corrector plate, a thick meniscus
lens that corrects the light entering the telescope
for the spherical mirrors. 90 mm primary mirror
at the bottom of the tube, and a secondary mirror
which is an aluminized spot on the back of the
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Illustration 1: Telescope Parts - side view

corrector. Which reflects the licgh back through a
hole in the center of the primary mirror to the
eyepiece. The optical train produces a ,250 mm
focal length and a focal ratio of f/ 3.9.
Altitude tension ad ustment knob: By
tightening and loosening this knob, you can
change the amount of tension in the altitude
(up/down) motion of the telescope.
Altazimuth base: The wooden base provides a
stable base for the telescope when placed on a
sturdy table, like a picnic table. Celestial objects
viewed through the telescope will appear to
slowly move due to the Earth's rotation. The
higher the power that faster this apparent motion.
EZ Finder II reflex sight: This finder does not
magnify. When properly aligned it puts a virtual
red dot on the object you're aiming at. The use of
the finder is discussed in the Getting Started
section.
Telescope securing knob: This allows the
telescope to be positioned fore and
aft in the mount for balance and
stowage. Three indentations on the
Dovetail bar are used for this
purpose. The telescope tube must
be supported by your hand when
moving from one indentation
position to another.
90º Star diagonal: Contains a right
angle prism to allow a convenient
viewing angle when looking up into
the sky. It also maked the image
right-side-up, and produces a mirror
image.
Focus knob: Alters the spacing of
the internal optical components to
focus the telescope. This provides
an extreme range of focus, so it is
possible to become 'lost' and have
difficulty in changing focus from
near to far objects. Rotate the knob
clockwise to focus on near objects,
and counterclockwise to focus on
more distant ones.
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Illustration 2: Telescope - rear view

Unstowing the telescope
from the vertical storage
position
The telescope is packaged in a cardboard box
with a built-in handle.
. Open the box.
2. Loosen the Altitude adjustment knob
(Illustration 2) enough so the telescope
can be rotated into a horizontal position
with the Telescope securing knob pointing
up, and tighten.
3. Supporting the telescope with one hand
unscrew the Telescope securing knob a
couple of turns and slide the telescope
forward to engage the center indentation
and re-tighten the Telescope securing
knob.
Getting Started
It’s best to get a feel for the basic functions of the
TableTop telescope during the day, before
observing astronomical objects at night. This way
you won’t have to orient yourself in the dark!
Find a spot outdoors where you’ll have plenty of
room to move the telescope, and where you’ll
have a clear view of some object or vista that is at
least /4 mile away. It is not critical that the
telescope be exactly level, but it should be placed
on flat ground or pavement to ensure smooth
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Illustration 3: Vertical Storage Position
Illustration 4: Telescope securing knob in
the orward storage indentation in the
Dovetail bar

movement. The telescope was designed
specifically for visual observation of astronomical
objects in the night sky.
4. Pull the Telescope up and out by grasping
the 90º Diagonal and place the telescope
on a sturdy table. It should look like
Illustration 3.
Placing the Ta leTop
One of the great assets of the TableTop Telescope
is its extremely portable size. Due to its overall
short length, you will find that viewing while
sitting down on the ground next to the telescope is
the most comfortable. If you wish to raise the
telescope off the ground so that it can be used
while standing or sitting in a chair, then a
platform, such as a milk crate or table can be
used.
Altitude and Azimuth (Aiming the
Telescope)
The TableTop altazimuth base permits motion
along two axes: altitude (up/down) and azimuth
(left/right). Moving the telescope up/down and
right/left is the “natural” way people search for
objects; which makes pointing the telescope
intuitive and easy.
Simply take hold of the 90º Diagonal and move it
left or right so that the base rotates. Move it up or
down in the same manner. Both motions can be
made simultaneously and in a continuous manner
for easy aiming. This way you can point to any
position in the night sky,from horizon to horizon.
Altitude Tension Adjustment
When aiming the telescope in altitude, you may
find that the optical tube is either too hard to
move or does not stay in place. Use the altitude
adjustment tension knob to change the amount of
tension between the optical tube and the
altazimuth base to find the right level of tension
to properly move and balance the telescope.
(Refer to Illustration 2 to identify the Altitude
Tension Knob).
Focusing the Telescope
Using Zoom eyepiece dialed to 2 mm aim the
optical tube so the front end is pointing in the
general direction of an object at least /4-mile
away. With your fingers, slowly rotate the focus
knob until the object comes into sharp focus. A
good method to ensure you’ve hit the exact focus
point is go a little bit beyond sharp focus until the
image starts to blur again, then reverse the
rotation of the knob and stop when sharp focus
has been achieved again. Note that it is possible
to become 'lost' and have difficulty in changing
focus from near to far objects. Rotate the knob
clockwise to focus on near objects, and
counterclockwise to focus on more distant ones.
Operating the EZ Finder II
Reflex Sight
The EZ Finder II reflex sight makes pointing your
telescope almost as easy as pointing your finger!
It’s a non-magnifying aiming device that
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Illustration 5: The EZ Finder II Re lex Sight

superimposes a dot on the sky, showing exactly
where the telescope is pointed. The EZ Finder II
works by projecting a tiny red dot produced by a
light emitting diode(LED), not a laser beam, onto
a lens mounted in the front of the unit. When you
look through the reflex sight, the red dot will
appear to float in space.
The first time you use the EZ Finder II you may
have to remove the clear plastic tab near the
battery cover; this tab prevents the batteries from
accidentally being drained during storage. Turn
the power knob clockwise until you hear the
“click” indicating that power has been turned on.
Look through the back of the reflex sight with
both eyes open to see the red dot.
Position your eye at a comfortable distance from
the back of the sight. The intensity of the dot is
adjusted by turning the power knob. For best
results when stargazing use the dimmest possible
setting that allows you to see the dot without
difficulty. Typically a dimmer setting is used
under dark skies and a bright setting is used under
light-polluted skies or daylight. (See Illustration
5.)
Aligning the EZ Finder II Reflex
Sight
When the EZ Finder II is properly aligned with
the telescope an object that is centered on reflex
sight’s red dot should also appear in or near the
field of view of the telescope’s eyepiece at lowest
power. Alignment of the sight is easiest during
daylight before observing at night.
. Without moving the main telescope, use
the EZ Finder II’s azimuth (left/right) and
altitude (up/down) adjustment knobs to
center the red dot on the object in the
eyepiece.
2. When the red dot is centered on the distant
object, check to make sure that the object
is still centered in the telescope’s field of
view. If not, re-center it and adjust the EZ
Finder II’s alignment again. When the
object is centered in the eyepiece and on
the reflex sight’s red dot, the EZ Finder II
is properly aligned with the telescope and
is ready to be used.
The EZ Finder II alignment should be checked
before every observing session. Choose any
distant target (during the day) or bright star (at
night), center the object in the telescope’s
eyepiece, and then adjust the knobs until the
object is centered on the red dot of the reflex
sight. (See Illustration 5.)
3. Aim the telescope at a distant object such
as a telephone pole or roof chimney and
center it in the telescope’s eye-piece. The
object should be at least /4 mile away.
Now, with the EZ Finder II turned on,
look though it. The object will appear in
the field of view near the red dot
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Illustration 6: The EZ Finder II superimposes a
tiny red dot onthe sky, showing right where the
telescope in pointing.

At the end of your observing session, be sure to
turn the power knob counterclockwise until it
clicks off. When the two white dots on the EZ
Finder II’s body and power knob are lined up, the
EZ Finder II is turned off.
Replacing the Battery
Replacement 3-volt lithium (CR-2032) batteries
are available from many retail outlets. Remove
the old battery by inserting a small flat-head
screwdriver into the slot on the battery cover and
gently prying open the cover. Then carefully pull
back on the retaining clip and remove the old
battery. Do not over bend the retaining clip. Then
slide the new battery under the battery lead with
the positive (+) side facing down and replace the
battery cover.
Turn off the finder power after use. The user
is responsible for purchasing and replacing the
battery if due to leaving the finder power on.
Using Your Telescope
hoosing an Observing Site
When selecting a location for observing, get as far
away as possible from direct artificial light such
as streetlights, porch lights, and automobile
headlights. The glare from these lights will
greatly impair your dark-adapted night vision.
Avoid viewing over rooftops and chimneys, as
they often have warm air currents rising from
them. Similarly, avoid observing indoors through
a window, either open or closed, because the
temperature difference between the indoor and
outdoor air will cause image blurring and
distortion. Window glass may also introduce
glare, internal reflections, or double-images into
your view.
If at all possible, escape the light-polluted city sky
and head for darker country skies. You will be
amazed at how many more objects are visible in a
dark sky!
“Seeing” and Transparency
Atmospheric conditions vary significantly from
night to night. “Seeing” refers to the steadiness of
the Earth’s atmosphere at a given time. In
conditions of poor seeing, atmospheric turbulence
causes objects viewed through the telescope to
“boil”. If, when you look up at the sky with your
naked eyes, the stars are twinkling noticeably, the
seeing is bad and you will be limited to viewing
with low powers (bad seeing affects images at
high powers more severely). Planetary observing
may also be poor.
In conditions of good seeing, star twinkling is
minimal and images appear steady in the
eyepiece. Seeing is best over- head, worst at the
horizon. Also, seeing generally gets better after
midnight, when much of the heat absorbed by the
Earth during the day has radiated off into space.
Especially important for observing faint objects is
good “transparency” – air free of moisture,
smoke, and dust. All tend to scatter light, which
reduces an object’s brightness. Transparency is
judged by the magnitude of the faintest stars you
can see with the unaided eye (6th magnitude or
fainter is desirable).
If you cannot see stars of magnitude 3.5 or
dimmer then conditions are poor. Magnitude is a
measure of how bright a star is – the brighter a
star is, the lower its magnitude will be. A good
star to remember for this is Megrez (mag. 3.4),
which is the star in the “Big Dipper” connecting
the handle to the “dipper”. If you cannot see
Megrez, then you have fog, haze, clouds, smog,
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or other conditions that are hindering your
viewing.
Tracking elestial Objects
The Earth is constantly rotating about its polar
axis, completing one full rotation every 24 hours;
this is what defines a “day”. We do not feel the
Earth rotating, but we see it at night from the
apparent movement of stars from east to west.
When you observe any astronomical object, you
are watching a moving target. This means the
telescope’s position must be continuously
adjusted over time to keep an object in the field of
view. This is easy to do with the TableTop
Telescope because of its smooth motions on both
axes. As the object moves off towards the edge of
the field of view, just lightly nudge the telescope
to re-center it.
Objects appear to move across the field of view
faster at higher magnifications. This is because
the field of view becomes narrower. Objects seen
through the eyepiece will be right side up but will
be reversed left-right.
Magnification Limits
Every telescope has a useful magnification limit
of about 2X per millimeter of aperture. This
comes to 80X for the 90mm TableTop Telescope
which is the magnification produced by the zoom
eyepiece when set to 7mm.
Moderate magnifications are what give the best
views. It is better to view a small, but bright and
detailed image than a dim, unclear, oversized
image.
What to Expect
So what will you see with your telescope? You
should be able to see bands on Jupiter, the rings
of Saturn, craters on the Moon, the waxing and
waning of Venus, and many bright binary stars.
Deep-sky objects are generally too faint at the
magnifications employed by this Maksutov-
Cassigrain telescope, but a few are bright enough.
Remember that you are seeing these objects using
your own telescope with your own eyes! The
object you see in your eyepiece is in real-time,
and not some conveniently provided image from
an expensive space probe. Each session with your
telescope will be a learning experience. Each time
you work with your telescope it will get easier to
use, and planetary and stellar objects will become
easier to find. Take it from us, there is big
difference between looking at a well-made full-
color NASA image in a lit room during the
daytime, and seeing that same object in your
telescope at night. One can merely be a pretty
image someone gave to you. The other is an
experience you will never forget!
Objects to Observe
Now that you are all set up and ready to go, one
critical deci- sion must be made: what to look at?
A. The Moon
With its rocky surface, the Moon is one of the
easiest and most interesting targets to view with
your telescope. Lunar craters, marias (dry lava
“seas”), and even mountain ranges can all be
clearly seen from a distance of 238,000 miles
away! With its ever-changing phases, you’ll get a
new view of the Moon every night. The best time
to observe our one and only natural satellite is
during a partial phase, that is, when the Moon is
NOT full. During partial phases, shadows are cast
on the surface, which reveal more detail,
especially right along the border between the dark
and light portions of the disk (called the
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“terminator”). A full Moon is too bright and
devoid of surface shadows to yield a pleasing
view. However it is the best time to trace out
crater rays. Make sure to observe the Moon when
it is well above the horizon to get the sharpest
images.
B. The Planets
The planets don’t stay put like the stars, so to find
them you should refer to Sky Calendar at our
website (OrionTelescopes.com), or to charts
published monthly in Astronomy, Sky &
Telescope, or other astronomy magazines. See
also the web site list at the back of these
instructions. Venus, Jupiter, Saturn and Mars are
the brightest objects in the sky after the Sun and
the Moon. The TableTop Telescope is capable of
showing you these planets in some detail. Other
planets may be visible but will likely appear star-
like. Because planets are quite small in apparent
size, using higher magnification is justified in
viewing these. Not all the planets are generally
visible at any one time.
JUPITER: The largest planet, Jupiter, is a great
subject for observation. You can see the disk of
the giant planet and watch the ever-changing
positions of its four largest moons – Io, Callisto,
Europa, and Ganymede. Also these moons pass
in front of Jupiter (transit), casting their shadows
on the planet, duck behind Jupiter (occultation),
or are eclipsed in Jupiter's shadow. These events
occur almost daily. See the Appendix for a
website where these times may be found.
SATURN: The ringed planet is a breathtaking
sight when it is well positioned. The tilt angle of
the rings varies over a period of many years;
sometimes they are seen edge-on (next time
2025), while at other times they are broadside and
look like giant “ears” on each side of Saturn’s
disk. A steady atmosphere (good seeing) is
necessary for a good view. You will probably see
a bright “star” close by, which is Saturn’s
brightest moon, Titan.
VENUS: At its brightest, Venus is the most
luminous object in the sky, excluding the Sun and
the Moon. It is so bright that sometimes it is
visible to the naked eye during full daylight!
Ironically, Venus appears as a thin crescent, not a
full disk, when at its peak brightness. Because it
is so close to the Sun, it never wanders too far
from the morning or evening horizon. No surface
markings can be seen on Venus, which is always
shrouded in dense clouds.
MARS: At it's closest some detail on the surface
of Mars can be seen. One of the polar caps can
usually be seen. These are mostly carbon dioxide.
Other surface features will have to wait until Mars
is closest to the Earth which occurs on average of
every 26 months. The next two closest Mars
dates are May 20, 20 6, and July 3 , 20 8. The
20 8 date is the closest Mars will get to the Earth
since it's closest of recorded history August 27,
2003. Mars during about 4 months centered on
the indicated dates will be the best for viewing.
C. The Stars
Stars will appear like twinkling points of light.
Even powerful telescopes cannot magnify stars to
appear as more than a point of light. You can,
however, enjoy the different colors of the stars
and locate many pretty double and multiple stars.
The gorgeous two-color double star Albireo in
Cygnus is a favorite. Defocusing a star slightly
can help bring out hints of color. See the
Appendix for a list.
D. Brighter Deep-Sky Ob ects
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Under dark skies, you can observe some of the
brighter deep-sky objects, including gaseous
nebulae, open and globular star clusters, and a
few galaxies. Even the brighter deep-sky objects
are very faint, so it is important that you find an
observing site well away from light pollution.
Take plenty of time to let your eyes adjust to the
darkness. Do not expect these objects to appear
like the photographs you see in books and
magazines; most will look like dim gray smudges.
Our eyes are not sensitive enough to see color in
deep-sky objects except in a few of the brightest
ones. But as you become more experienced and
your observing skills get sharper, you will be able
to ferret out more and more subtle details and
structure. See the Appendix for a list.
Viewing Hints
Amateur astronomy can be an entertaining and
educational activity for the entire family.
Astronomy is also a serious scientific pursuit. As
with any science you will achieve the best results
by following some basic guidelines. These
recommendations will assist you in getting the
most out of the telescope. This is just a sample of
suggested techniques; for more helpful tips please
visit the Learning Center at
OrionTelescopes.com.
Light Pollution
Most of us live where city lights interfere with
our view of the heavens. As our metropolitan
areas have become more developed, the scourge
of light pollution has spread, washing out many
stars and nonstellar celestial objects from our
sight. Faint deep sky objects become difficult or
impossible to see through the murk of light
pollution. Even bright nebulas like the Orion and
Lagoon Nebulas lose much of their delicate detail.
The Moon and planets are not affected; they
require steady air more than dark skies, so they
remain good targets for city-dwelling observers.
The International Dark-Sky Association is waging
the fight against light pollution. The IDSA was
founded in 988 with the mission of educating the
public about the adverse impact that light
pollution has on the night sky and astronomy.
Through educational and scientific means, the
nonprofit IDA works to raise awareness about the
problem and about measures that can be taken to
solve it.
Do you need help dealing with local officials to
control street or building lighting in your area?
The IDA’s extensive support materials can show
you how. Help preserve dark skies, join the IDA
today! For information, write to IDA, 3225 N.
First Ave., Tucson, AZ 857 9-2 03 or visit their
website: www.darksky.org. The best way to
avoid immediate problems with light pollution,
however, is to take your telescope to where there
are dark skies. You will be amazed at how many
stars you can see when you get away from the city
lights.
Do You Wear Eyeglasses?
If you wear eyeglasses, you may be able to keep
them on while you observe. In order to do this,
your eyepiece must have enough “eye relief” to
allow you to see the entire field of view with
glasses on. You can try looking through the
eyepiece first with your glasses on and then with
them off, to see if the glasses restrict the view to
only a portion of the full field.
If the glasses do restrict the field of view, you
may be able to observe with your glasses off by
just refocusing the telescope to your unaided
vision. If your eyes are astigmatic, images will
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