VISITORS FROM SPACE

The paths of dozens of comets are known to astronomers. Some pass the Earth only once, but others, on elliptical orbits, reappear at regular intervals. The more important of these 'periodical' comets are listed here. Unlike solar and lunar eclipses, comets can be seen from all parts of the globe. Halley's Comet is the only major periodical comet visible to the naked eye.

Name

Orbital Period (years)

Date when next Visible

Schwassmann-Wachmann

15

Visible throughout orbit with a telescope

Halley

76.1

2061 - 62

D'Arrest

6.2

2004 - 05

Encke

3.3

2003 - 04

Borrelly

6.8

2007 - 08

Pons - Winnecke

6.3

2006 - 07

Finlay

6.9

2008 - 09

Faye

7.4

2004 - 05

Tuttle

13.8

2007 - 2008

Crommelin

27.9

2011

Not being an expert on this topic, the calculated dates had to be spread as I do not know at exactly what time of year they last appeared and the fraction of the year of orbit may run into the higher of the actual dates given. E.g. Faye should be due in 2004, but with the point four of a year to add, it may appear in early 2005, depending whether it appeared early or late in 1997. Axiompc.
If you are really into Comets and the like then visit this superb Comet Site. It's packed with information on this subject.