The light curve is strongly asymmetric to the perihelion.
It starts brightening rapidly about half a year before the perihelion
passage. It keeps very faint before that. The brightening continues
after the perihelion passage, and it becomes brightest about three
weeks after the perihelion passage. After the maximum brightness, it
fades rapidly for about 100 days. Then the fading pace turns to be
slow, and it keeps observable while fading gradually along a 10 log r
Kazuo Kinoshita's calculation revealed that it had been moving along a
far orbit with a perihelion distance of 1.6 A.U. until 1965. Now it is
in the close and bright period with a perihelion distance of 0.9 - 1.0
A.U. But the perihelion distance will be increased up to 2.0
A.U. again 200 years after now.