Comet Hyakutake
Comet Hyakutake, long-period comet that, because of its relatively close passage to Earth, was observed as one the brightest comets of the 20th century. It was discovered on January 30, 1996, by the Japanese amateur astronomer Hyakutake Yuji, using large binoculars. Visible to the naked eye in late February of that year, it became spectacular in March, developing a long blue ion (plasma) tail that stretched across the sky and a white dust tail that was much shorter but wider. It finally became five or six times as bright as a first-magnitude star when it passed Earth at a mere 0.1 astronomical unit (AU; 15 million km [9.3 million miles]) on March 24–25. It faded away in early April and reached perihelion (closest distance to the Sun) at 0.23 AU (34 million km [21 million miles]) from the Sun on May 1.