STAR ATLAS
Astronomer Book
USING THE STAR MAPS
In the Star Atlas the stars are mapped month by month, first for the
Northern Hemisphere, then for the Southern. For each month the stars
you can see are shown for an observer facing north or facing south. If you
hold the map for a particular month up in front of you, while facing either
north or south, then you will be able to identify the stars that are visible to the
naked eye.FINDING THE PLANETS
Observing Mars, Jupiter and Saturn
The positions of the planets visible to the naked eye that orbit the Sun further
out than the Earth are marked on the relevant charts. As these positions
change over time, the positions marked indicate where the planets will be
when at opposition for the year indicated.Opposition
Opposition is a term used to describe when a planet lies opposite the Sun in
the sky, and appears at its brightest. At this time, a planet will be visible allnight, rising around sunset and setting around dawn. Of the planets marked,
Mars moves quite rapidly across the sky before and after opposition while
Jupiter and Saturn don't.Observing Mercury and Venus
The inner planets, Mercury and Venus, never wander too far from the Sun
and are best seen when they are at elongation.Elongation
Elongation is a point in the orbits of Mercury and Venus when the planet
will appear at its greatest distance from the Sun. In order to determine the
best time to see the two inner planets, we've listed their elongation dates in
tables. Eastern elongation means the planet is visible in the western part of
the sky after sunset, while western elongation means it's a morning object,
rising before the Sun.
Mercury can never appear to wander from the Sun by more than 28
degrees while Venus can fare much better with a maximum elongation of
47 degrees.Mercury in the clouds in the twilight skies.