Comet Tempel-Tuttle — Comet Tempel-Tuttle is an inherently faint and typically unspectacular comet that has only been observed on a few apparitions over the past 600 years.
Its most recent apparition was in 1998, when it reached perihelion on February 28. As expected, it showed little activity, and only a small tail.
However, further inspection shows that this comet is more interesting than the first glance suggests. Its orbit is oriented in such a way that the comet makes a relatively close approach to the Earth every few apparitions.
The 1998 apparition was one such case, when the comet passed within 0.36 AU (33 million miles) of the Earth on January 17. More importantly for the casual sky observer is the fact that Tempel-Tuttle is associated with the Leonid meteor shower, which has historically been very spectacular in the few years after T-T passes perihelion.
Comet Tempel-Tuttle was “discovered” independently by William Tempel in December 1865 and by Horace Tuttle in January 1866. After this apparition, calculations showed that the comet was in an elliptic orbit with a 33-year period.
This information was then used to prove that Tempel-Tuttle was the same comet that had been observed in the year 1366 and again in 1699. The orbit determination was also used to show that T-T was associated with the Leonid meteor shower that occurs every year in November.
Even though astronomers searched for it in 1899 and again in 1932, Tempel-Tuttle was not seen again until 1965, when it was observed as a faint, 16th magnitude object.