"For comet enthusiasts, the potential
to glimpse three different naked-eye comets within a span of a few weeks is an
anomaly. On average, a comet visible to the unaided eye appears about once every
five years." (National
Geographic News)
"Yet this is an auspicious
circumstance, as Machholz became the fifth naked-eye comet of 2004. Twice
before, in 1911 and again in 1970, four comets managed to reach naked-eye
brightness within a single calendar year. But when Andrew Pearce of Noble
Falls in Western Australia saw Comet Machholz without any optical aid on Nov.
19, it put 2004 into the books as a record year for naked-eye comets."
(MSNBC)