Saturn Opposition 2003
Saturn is one of the
splendors of the night sky. Few people forget their first glimpse through a
telescope at the planet and its expansive rings hovering against the velvet
background of space.
While the best views
of Saturn will be during the cold winter months, few will disagree that it is
worth the trouble to venture out into the frosty air to experience 
the
beauty of this, the most recognizable celestial object.
Saturn begins to rise
high in the evening sky in late October and reaches opposition (where the Sun
and Saturn appear in opposite directions from Earth's perspective) on December 31st .
Saturn
with its rings will be 1.8 times larger than Mars was at its recent opposition.
Mars was 25 arc seconds in diameter (angular size) during the opposition in
2003. Saturn with its rings will be about 46 arc seconds in angular size. Even
though Saturn is much further away than Mars, Saturn is much larger. Mars was
about 35 million miles away at opposition where as Saturn will be about 800
million miles away.
Viewing specifics for
opposition 2003 are as follows:
Opposition Specifics:
Date:
Magnitude: -0.3
Diameter: 20.7"
Declination: +23 degrees
Saturn's next opposition will
not be until
During the 2003 opposition the
orientation of the rings will be particularly good. This year’s opposition will
reveal an optimal view with little or no shadowing on the planet and nearly
optimal brightness.
Any telescope with at least a 30x magnification will reveal the rings.
But the views become truly exquisite with a 100-200 mm (approximately 4-8 inch)
aperture instrument.
You will be able to easily see a gap in the
rings known as Cassini's Division. There is another
division near the outer edge which can be seen in the larger telescopes. That
feature is called the Encke's Division. You will also
be able to see belts on the planet itself.
For approximately one to four months either side of opposition, Saturn's
shadow across its rings is very apparent.
Saturn's rings
are the planet's most endearing telescopic feature. Throughout the 2003-2004
viewing cycle, the rings display themselves to Earth through an average tilt of
-25 degrees. Due to the ring tilt, we see the rings and moons of Saturn from
south of the ring plane. Saturn’s rings
are incredibly thin for their size. The ring thickness is about 3,280 feet or
nearly 2/3 of a mile.
At last count, Saturn had 31 moons. The
largest, Titan is easily visible in any telescope. At west and east maximum
elongation the moon appears as an 8th magnitude object orbiting approximately 5
ring diameters from the planet. Saturn's other visible moons are Enceladus, Tethys, Dione, and Rhea.
Saturn is the
second largest planet in our solar system with a diameter of 74,900 miles which is 9.5 times
larger than Earth’s diameter. To put it
into perspective, Saturn and its rings would just fit in the distance between
Earth and the Moon. It is the sixth
planet in the solar system at distance of 840 million miles from the Sun. The rotational period for Saturn is 10 hours,
39 minutes, meaning one there are a little over 10 hours in each Saturnian day.
Its atmosphere is
primarily composed of hydrogen, with small amounts of helium and methane. It
can be said that it is some what cold and windy on Saturn, with
velocities reaching 1,100 miles
an hour at the equator and average atmospheric
temperatures of about -220 degrees Fahrenheit.
Keeping that in mind is sure to make you feel warmer as you view Saturn
in the cold winter months.
It was Galileo in
the early 1600’s who was the first to observe Saturn's rings
with his 20-power telescope. Interestingly, he was quite confused by the
ring apparition through his poor quality optics. Originally he speculated that
the rings were "handles" or large moons on either side of the planet.
In 1655, Dutch astronomer, Christiaan Huygens was the
first to correctly discern the nature of the rings of Saturn. It was not until
1675 that Italian Astronomer Giovanni Domenico Cassini was able to resolve the main division in the ring
structure, thus bearing his name.
On