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amazed at how much better the view is from dark country
skies compared to the view from light-polluted city or subur-
ban skies. (Brighter objects, such as the Moon and planets,
aren’t affected much by city lights, however.) Don’t be afraid
to load the telescope into your car for a trip to the hills. As
long as the telescope doesn’t bounce around too much, it
won’t get damaged in transit.
Setup and Field Use
When selecting a location for observing, be sure to place the
telescope 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 night
vision. The telescope should be set up on a relatively level
surface. A grass or dirt surface is preferable to asphalt,
because asphalt radiates more heat at night, which disturbs
the air and compromises your view.
Focusing
Slowly turn one of the two focusing knobs back and forth to
bring the object you’re viewing into sharp focus. For viewing
nebulas and galaxies, which appear faint and “fuzzy,” it’s best
to focus on stars in the same field of view. You’ll know the
deep-sky object is in focus when the stars around it appear
as sharp pinpoints.
5. Observing Tips and
Techniques
Seeing Limitations
Atmospheric conditions vary significantly from night to night.
“Seeing” refers to the steadiness of the air 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 just your eyes, the stars are twinkling
noticeably, 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 very limit-
ed. Make sure you are not looking over buildings or any other
source of heat; that will also cause the image to become dis-
torted. In conditions of good seeing, star twinkling is minimal
and images appear steady in the telescope’s field of view.
Cooling Your Telescope
All optical instruments need time to reach “thermal equilibri-
um.” When moved from a warm indoor location into the
cooler nighttime air, a telescope’s optics must cool to the out-
door temperature to achieve optimal image quality. The
bigger the instrument and the larger the temperature
change, the more time is needed for the optics to equilibrate.
For your SpaceProbe telescope, allow about an hour before
you start observing. In very cold climates (below freezing), it
is essential to store the telescope as cold as possible to min-
imize equilibration time. If the scope has to adjust to more
than a 40° temperature change, allow two to four hours.
Do You Wear Eyeglasses?
If you wear eyeglasses, you may be able to keep them on
while you observe if your eyepieces have enough eye relief
to allow you to see the whole field of view. You can try this by
looking through the eyepiece first with your glasses on and
then with them off, and see if the glasses restrict the view to
only a portion of the full field. If they do, you can easily
observe with your glasses off by just refocusing the telescope
the needed amount.
Let Your Eyes Adapt to the Darkness
Don’t expect to go from a lighted house into the darkness of
the outdoors at night and immediately see faint nebulas,
galaxies, and star clusters—or even very many stars, for that
matter. Your eyes take about 30 minutes to reach perhaps
80% of their full dark-adapted sensitivity. Many observers
notice improvements after several
hours in total darkness. As
your eyes become dark-adapted, more stars will glimmer into
view and you’ll be able to see fainter details in objects you
view. Exposing your eyes to very bright daylight for extended
periods of time can adversely affect your night vision for days.
So give your eyes a while to get used to the dark before you
begin observing.
To see what you’re doing in the darkness, use a red-filtered
flashlight rather than a white light. Red light does not ruin your
eyes’ dark adaptation like white light does. A flashlight with a
red LED light is ideal, or you can cover the front of a regular
incandescent flashlight with red cellophane or paper. Beware,
too, that nearby porch lights, streetlights and automobile
headlights will ruin your night vision.
6. Astronomical Viewing
How to Find Interesting Celestial Objects
To find celestial 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 sim-
ple 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.
A good star chart or atlas can come in very handy for helping
find objects among the dizzying multitude of stars overhead.
Except for the Moon and the brighter planets, it’s pretty time-
consuming and frustrating to hunt for objects randomly,
without knowing where to look. You should have specific tar-
gets in mind before you begin looking through the eyepiece.
Start with a basic star atlas, one that shows stars no fainter
than 5th or 6th magnitude. In addition to stars, the atlas will
show the positions of a number of interesting deep-sky
objects, with different symbols representing the different types
of objects, such as galaxies, open star clusters, globular clus-
ters, diffuse nebulas, and planetary nebulas. So, for example,
your atlas might show a globular cluster sitting just above the
lid of the “Teapot” pattern of stars in Sagittarius. You then
know to point your telescope in that direction to home in on the
cluster, which happens to be 7th-magnitude M28.
