The periodic comet 2P/Encke has been observed at more returns
than any other. Since it never gets further from the Sun than 4
astronomical units - just beyond the asteroid belt - it is now
possible with modern observing techniques to follow it
continuously.
Comet 2P/Encke is in an unusual orbit with a period of only 3.3
years, the shortest by far of any periodic comet, which is why it
has been observed at so many returns. Independent 'discoveries'
of it were made in 1786 by Pierre Mechain, in 1795 by Caroline
Herschel and in 1805 and 1818 by Jean Louis Pons. In 1819,
Johann Encke showed that all these apparitions were one and
the same comet, and computed its orbit. Since then, 53 further
returns to perihelion have been logged (up to 1997). This
compares with the 30 recorded returns of Halley's Comet
between 239 BC and 1986.
|
(1998).ISO/media/record_breakers/graphics/obscomet.jpg)