Collimation Of Your Telescope's Optics - Orion Observer 90mm Instruction Manual

Focusing the Telescope
To focus the telescope, turn the focus wheels (Figures 14
and 15) forward or back until you see your target object (e.g.,
stars, the Moon, etc.) in the eyepiece. Then make finer adjust-
ments until the image is sharp. If you're having trouble achiev-
ing initial focus, rack the focuser drawtube all the way in using
the focus wheels, then while looking into the eyepiece slowly
turn the focus wheels so that the drawtube extends outward.
Keep going until you see your target object come into focus.
Note that when you change eyepieces you may have to adjust
the focus a bit to get a sharp image with the newly inserted
eyepiece.
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
deep-sky objects. Do not expect to see color as you do in
NASA photos, since those are taken with long-exposure cam-
eras and have "false color" added. Our eyes are not sensitive
enough to see color in deep-sky objects except in a few of the
brightest ones.
Objects to Observe
Now that you are all set up and ready to go, what is there to
look at in the night sky?
A. The Moon
With its rocky surface, the Moon is one of the easiest and
most interesting objects to view with your telescope. Lunar
craters, maria, 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 satel-
lite 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 "terminator").
A full Moon is too bright and devoid of surface shadows to
yield a pleasing view. Make sure to observe the Moon when it
is well above the horizon to get the sharpest images.
Use an optional Moon filter to dim the Moon when it is very
bright. It simply threads onto the bottom of the eyepieces (you
must first remove the eyepiece from the focuser to attach a
filter). You'll find that the Moon filter improves viewing comfort,
and helps to bring out subtle features on the lunar surface.
B. The Planets
The planets don't stay put like the stars, so to find them you
should refer to the monthly star charts at OrionTelescopes.
com, or to charts published monthly in Astronomy, Sky &
Telescope, or other astronomy magazines. Venus, Mars,
Jupiter, and Saturn are the brightest objects in the sky after
the Sun and the Moon. Other planets may be visible but will
likely appear star-like. Because planets are quite small in
apparent size, optional higher-power eyepieces or a Barlow
lens are recommended and often needed for detailed obser-
vations.
B. The Sun
You can change your nighttime telescope into a daytime Sun
viewer by installing an optional full-aperture solar filter over
the front opening of the telescope. The primary attraction is
sunspots, which change shape, appearance, and location
daily. Sunspots are directly related to magnetic activity in the
Sun. Many observers like to make drawings of sunspots to
monitor how the Sun is changing from day to day.
Important Note: Do not look at the Sun with any optical instru-
ment without a professionally made solar filter placed over the
front aperture of your telescope, or permanent eye damage
could result.
Important Note: Do not look at the Sun with any opti-
cal instrument without a professionally made solar filter
placed over the front aperture of your telescope, or per-
manent eye damage could result.
D. 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 famous "Double-Double" in the constellation Lyra and the
gorgeous two-color double star Albireo in Cygnus are favor-
ites. Defocusing a star slightly can help bring out its color.
E. Deep-Sky Objects
Under dark skies, you can observe a wealth of fascinating
deep-sky objects, including gaseous nebulas, open and
globular star clusters, and different types of galaxies. Most
deep-sky objects are very faint, so it is important you find an
observing site well away from light pollution.
To find deep-sky objects with your telescope, you first need
to become reasonably familiar with the night sky. Unless you
know how to recognize the constellation Orion, for instance,
you won't have much luck locating the Orion Nebula. A simple
planisphere, or star wheel, can be a valuable tool for learning
the constellations and seeing which ones are visible in the
sky on a given night. Once you have identified a few constel-
lations, a good star chart, atlas, or astronomy app will come in
handy for helping locate interesting deep-sky objects to view
within the constellations.
Do not expect these objects to appear like the photographs
you see in books and on the internet; 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 sub-
tle details and structure.
VI. Collimation of Your
Telescope's Optics
Collimation is the process of adjusting the optics of a tele-
scope so they are precisely aligned with one another and
with the telescope tube. Accurate collimation is important to
ensure the peak performance of your telescope, so it should
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