tion periods of the various features. The procedure is to
time the moment when the feature crosses the central
meridian of the planet. The central meridian is easy to
locate, because of the polar flattening of the globe, and the
timings can be made with remarkable accuracy. The longi-
tude of the feature can then be found by using tables givenTHE SOLAR SYSTEM
▼ Cassini view of Jupiter
taken on 31 December 2000.
The smallest features visible
are approximately 60 km
(40 miles) across.in yearly astronomical almanacs. When Jupiter is suitably
placed in the sky, a whole rotation can be covered during
a single night’s observing.
Jupiter is certainly one of the Solar System’s most
intriguing worlds. There is always plenty to see, and no-
one knows just what will happen next!C Atl of Univ Phil'03stp 2/4/03 3:08 pm Page 97