Copyright © 1996-2002 Astronomical Society of South Australia, Inc. All rights reserved.
What will you see?
Hopefully you will witness one of natures greatest spectacles. Unlike many
recent eclipses, chances are that the weather in the South Australian outback
will provide a perfect cloud free and pollution free sky.
The first sign of the eclipse on Earth will be when the Moon's disc first
touches the Sun, this is known as First Contact. The time of First Contact
depends on where you are, relative to a particular eclipse. At First Contact,
the Moon begins to take a "bite" out of the Sun, as the day goes on,
this "bite" gets larger and larger.
As the moment of totality approaches, and the Sun is nearly covered, shadow
bands might be seen; narrow bands of shadow and light racing across the ground.
These are multiple images, caused by irregular refraction in the Earth's
atmosphere, of the remaining "slice" of the Sun. If you are standing
near or under trees, you may see multiple images of the crescent Sun being
projected on the ground by the "pinhole camera" effect of the leaves.
As the Moon moves to cover the Sun, events proceed very quickly. The Moon's
shadow may be seen rushing in very quickly from the west. The remaining crescent
of the Sun gradually shrinks to a sliver, and then breaks up into distinct
points of light, known as Baily's Beads. These are caused by the Sun shining
through valleys around the visible face of the moon. Because the Moon's surface
isn't equal all the way round, the display of Baily's Beads isn't consistent,
but depends on the angle from which the Moon approaches the Sun.
The Moon's irregularity can also have an effect on the duration and width of the
total eclipse. When only one point of light is left, a beautiful diamond ring
effect may be observed, with the last brilliant point of light transfixed on the
Moon's outline. Then this last glimmer vanishes, as the leading side or limb of
the Moon touches the farther limb of the Sun, at a moment known as Second
Contact. This is the first instant of the total eclipse.
During totality, the sky goes dark; not quite as dark as night, and with strange
shadow effects caused by scattered light from the edge of the eclipse; the
horizon still appears quite light, and the whole landscape takes on a strange
appearance. Birds go home to roost, bees stop flying, and some flowers may begin
to close as if for the night; nature seems to hold its breath. In the sky above
hangs the black disc of the Moon, surrounded by a faint halo, like a negative
Sun. The Sun's corona, far too faint to be seen at any time other than a total
eclipse, streams out from the Moon in all directions; some streamers reach
several times the size of the Sun before fading away.
For a few seconds after the beginning of totality, and again just before the
end, the Sun's lower atmosphere, the chromosphere, may be seen, as a reddish
glow around the edge of the Moon. Some solar prominences may also be seen, as
spectacular arcs of glowing red gas around the Sun. Around the Sun, with the sky
nearly dark, some of the brighter stars, and particularly planets, may be seen.
After totality the end of the total eclipse is the reverse of the beginning.
Totality ends at Third Contact, the moment at which the Moon begins to uncover
the Sun once again, a diamond ring, Baily's Beads, and shadow bands may be seen.
After third contact, the Sun is progressively uncovered by the Moon, and normal
daylight returns. The shadow on the Sun shrinks, until it vanishes altogether at
the moment of Fourth Contact.
Safe viewing of an eclipse
Warning - Observing the Sun is Dangerous. Do not look
directly at the Sun, unless you are using either a solar filter or
"eclipse sunglasses" specially designed
to protect your eyesight.
If you do not have these filters, then project an image of the sun, through a
small hole onto a flat surface, and watch the image. If you're not sure what to
do, then observe with someone who does know how to safely observe an eclipse.
When the moon partially covers the sun, it is tempting to look directly at the
sun. However, the sun is just as dangerous then as it is when the moon is not
partially covering it. If you look directly at the sun
during the partial eclipse, serious permanent damage can occur to your retina
(part of the eye). It is only safe to look at a solar eclipse when
the moon completely covers the disk of the sun and the corona is visible. There
are safe ways of observing an eclipse, such as using a pinhole camera or
projecting a telescope image onto a sheet of paper.
The totally eclipsed sun may be safely viewed without protection; but watch out
for the sudden return of sunlight!