-33-
implies air motion in the Earth's atmosphere, and under
these conditions resolution of fine detail (on the surface
of Jupiter, for instance) will generally be limited. When
the air is steady, stars appear to the naked eye as un-
twinkling points of unchanging brightness, and it is in
such a situation that the full potential of the telescope
may be realized: higher powers may be used to advantage,
closer double stars resolved as distinct points, and fine
detail observed on the Moon and planets.
Several basic guidelines should be followed for best results
in using your telescope:
1. .Try not to touch the eyepiece while observing. Any
vibrations resulting from such contact will immediate-
ly cause the image t9 move.
2.
_ Allow your eyes to become "dark-adapted" prior to making
serious observations. Night adaptation generally re-
quires about 10 to 15 minutes for most people.
3. Let the telescope "cool down" to the outside environ-
mental temperature before making observations. Temper-
ature differentials between a warm house and cold out-
side air require about 30 minutes for the telescope's
optics to regain their true and correct figures.
During this period the telescope will not perform well.
A good idea is to take the telescope outside 30 minutes
before you want to start observing.
j
I
~ t
j I
4. If you wear glasses and do not suffer from astigmatism,
take your glasses off when observing through the tele-
scope. You can re-focus.the image to suit your bwn
eyes. Observers with astigmatism, however; should
keep their glasses on, since the telescope cannot
correct for this eye defect.
5. Avoid setting up the telescope inside a room and ob-
serving through an open window (or, worse yet, through
a closed window!). The air currents caused by inside/
outside temperature differences will make quality
optical performance impossible.
6. Perhaps most importantly of all, avoid "overpowering"
your telescope. The maximum usable magnification at
any given time is governed by the seeing conditions.
If the telescopic image starts to become fuzzy as you
increase in power, drop down to a reduced magnifica-
tion. A smaller, but brighter and sharper, image is
far pr~ferable to a larger, but fuzzy and indistinct,
one.
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