Using Your Telescope; Tracking Celestial Objects - Orion 10022 StarMax Instruction Manual

Figure 10:
Mounting the TableTop base on a photo tripod
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.

Using Your Telescope

Choosing 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 view-
ing 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 tem-
perature 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 turbu-
lence 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 lim-
ited 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.
Figure 11:
Making optional adjustments to the azimuth tension
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 con-
ditions 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, or other conditions that are hindering your
viewing.

Tracking Celestial Objects

The Earth is constantly rotating about its polar axis, complet-
ing 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 watch-
ing 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 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 high-
er magnifications. This is because the field of view becomes
narrower. Objects seen through the eyepiece will be upside
down and reversed left-to right on reflectors. On telescopes
that accept a diagonal the image will be right side up. Star
diagonals will still be reversed left-right, correct image diag-
onals will provide images that are right side up and non-
reversed, as seen with the naked eye.
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