How to see a newly-discovered green comet this week, before it vanishes for 400 years

Meet the comet Nishimura.

A newly-discovered green comet is zipping by Earth and is now visible for the first time in more than 400 years.

Comet Nishimura was discovered by amateur Japanese astronomer Hideo Nishimura on Aug. 11 and named after him.

Nishimura first spotted it by taking long exposure shots using a Canon digital camera and a telephoto lens.