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S
ince the dawn of mankind there have
been independent thinkers who have
sought to understand the nature of the
Universe and our relationship to it. It is per-
haps the city or suburban observer who feels
the call of the cosmos most intensely when he
or she experiences the majesty of the night
sky from a truly rural location for the very first
time. Assuming that you have been overawed
by a similar experience, how do you go about
becoming an astronomer? Perhaps the first
step should be a trip to your local library to
find out where and when your local astro-
nomical society meets. There are over a hun-
dred such groups in the United Kingdom
alone, so there is bound to be a town near you
that has one.
Getting started: When we leave the cosy con-
fines of the living room and enter the realm of
the night we lose many of our everyday
frames of reference when we look up at the
broad expanse of the sky. Familiar visual
clues to judge size and distance are useless
against the starry background where every-
thing is so exceedingly remote as to be an
infinite distance away. In fact, it is convenient
to imagine the stars as being fixed upon the
inside surface of a vast hemisphere, or dome,
of infinite radius centred on your location -
this concept is known as the celestial sphere,
and it must be said that from a pitch-black
location the heavens do, indeed, appear to be
an enormous dome above our heads and rest-
ing on the horizon.
Over the years astronomers have convenient-
ly divided up the celestial sphere into grids
much like that of the lines of latitude and lon-
gitude that crisscross a terrestrial globe, such
that all objects in the sky can be given a pre-
cise coordinate for later reference. When you
become more proficient in your observing
you will refer to detailed "road maps" of the
stars that will use these very coordinate sys-
tems, but for now you need not worry about
them. Star charts are of little use to the novice
since many are confusingly covered with
lines, labels which frequently fail to give any
indication as to how large a constellation (or
star group) will appear to the naked eye.
Joining the dots... : If you were good at see-
ing the pictures in those dotty puzzles that we
used to draw around as a child, then you will
have a distinct advantage when it comes to
recognising and remembering constellation
patterns! It is as well to note that the constel-
lation outlines are entirely arbitrary – the
familiar figures of Hercules, Leo and Orion are
but three of the eighty-eight groups known to
astronomers that are largely the result of the
classicists' fertile imaginations. Note, too,
that the stars of any given constellation are
not necessarily associated with one another:
they are in reality at greatly differing distances
from us.
Finding that first constellation: A casual look
at the moonless night sky, particularly from a
rural location, will reveal so many thousands
of stars that the absolute beginner will feel
utterly lost and bewildered. However, the way
to start is to locate a particularly prominent
star pattern and use it as a starting point. For
the winter observer there is no better celestial
marker than the constellation of Orion, which
straddles the celestial equator and is therefore
visible from anywhere on the surface of the
Earth.
Getting a sense of scale: Using a star chart
from a monthly magazine that depicts the sky
to the east in December you will get an
impression of how large Orion appears in
relation to the other constellations that border
it, but just how big will it seem to the unaided
eye? To get a sense of scale it is very conve-
nient to use the outstretched hand at arms
length as a convenient guide. You will discov-
er that the distance from the tip of your little
finger to that of your thumb will be just suff i c i e n t
Get to know the sky...
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