Orion AstroView 9005 - Manual (Page 14)

C. the Planets
The planets don’t stay put like the stars (they don’t have fixed
R.A. and Dec. coordinates), so you’ll have to refer to charts
published monthly at our website, www.telescope.com, or in
monthly magazines like Astronomy, Sky & Telescope, to
locate them. Venus, Mars, Jupiter, and Saturn are the bright-
est objects in the sky after the Sun and the Moon. Not all four
of these planets are normally visible at any one time.
JUPITER The largest planet, Jupiter, is a great subject to
observe. 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. If atmospheric conditions
are good, you may be able to resolve thin cloud bands on the
planet’s disk.
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, while at
other times they are broadside and look like giant “ears” on
each side of Saturn’s disk. A steady atmosphere (good see-
ing) is necessary for a good view. You might see a tiny, bright
“star” close by; that’s 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 If atmospheric conditions are good, you may be able
to see some subtle surface detail on the Red Planet, possibly
even the polar ice cap. Mars makes a close approach to Earth
every two years; during those approaches its disk is larger
and thus more favorable for viewing.
D. Stars
Stars will appear like twinkling points of light in the telescope.
Even powerful telescopes cannot magnify stars to appear as
more than points 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 the image of 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 glob-
ular star clusters, and different types of galaxies. Most
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. Don’t expect these
subjects 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 such faint objects.)
But as you become more experienced and your observing
skills get sharper, you will be able to discern more subtle
details.
Remember that the higher the magnification you use, the dim-
mer the image will appear. So stick with low power when
observing deep-sky objects, because they’re already very
faint.
Consult a star atlas or observing guide for information on find-
ing and identifying deep-sky objects. A good source to start
with is the Orion DeepMap 600.
7. Astrophotography
Several different types of astrophotography can be success-
fully attempted with the AstroView 120ST:
Moon Photography
This is perhaps the simplest form of astrophotography, as no
motor drive is required. All that is needed is a T-ring for your
specific camera model. Connect the T-ring to your camera
body, and then thread the T-ring onto the rear of the focuser
drawtube (remove the star diagonal first).
Now you’re ready to shoot. Point the telescope toward the Moon,
and center it within the camera’s viewfinder. Focus the image
with the telescope’s focuser. Try several exposure times, all less
than 1 second, depending on the phase of the moon and the
ISO (film speed) of the film being used. A remote shutter release
is recommended, as touching the camera’s shutter release can
vibrate the camera enough to ruin the exposure.
This method of taking pictures is the same method with which
a daytime, terrestrial photograph could be taken through the
AstroView 120ST.
Planetary Photography
Once basic Moon photography has been mastered, it’s time to
get images of the planets. This type of astrophotography also
works to get highly magnified shots of the Moon. In addition to
the T-ring, you will need a Universal 1.25" Camera Adapter. The
EQ-3 Motor Drive System (single or dual-axis) is also required.
This is because a longer exposure is necessary, which would
cause the image to blur if no motor drive was used for tracking.
The equatorial mount must be accurately polar aligned, too.
As before, connect the T-ring to your camera. Before connect-
ing the camera adapter to the T-ring, an eyepiece must be
inserted and locked into the body of the camera adapter. Start
by using a medium-low power eyepiece (about 25mm); you
can increase the magnification later with a higher-power eye-
piece. Then connect the entire camera adapter, with eyepiece
inside, to the T-ring. Insert the whole system into the tele-
scope’s focuser drawtube and secure firmly with the
thumbscrew.
Aim the telescope at the planet (or Moon) you wish to shoot. The
image will be highly magnified, so you may need to use the
finder scope to center it within the camera’s viewfinder. Turn the
motor drive on. Adjust the telescope’s focuser so that the image
appears sharp in the camera’s viewfinder. The camera’s shutter
is now ready to be opened. A remote shutter release must be
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