The brightening and fading is rapid along a 25 log r formula.
However, there is some variation of its brightness among every
apparition. The absolute magnitude seems to vary between 4.0 and 5.2
mag. It was faint in 1991, but bright in 1999.
Kazuo Kinoshita's calculation revealed that it has been getting closer
to the Sun gradually. The perihelion distance has been reducing from
1.8 A.U. down to 1.5 A.U. during about 260 years between 1843 and
2102.
Returns and Appearances
Discovered
Appeared
Not observed
Appeared before discovery
Not observed before discovery
Returns in the future