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

Meet the comet Nishimura. Dan Bartlett/NASA hide caption

toggle caption Dan Bartlett/NASA

Meet the comet Nishimura.

Dan Bartlett/NASA

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 and named after him.

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

What is it?

When our solar system first formed, huge amounts of debris were left over. So what we see as a comet is a chunk of dirty ice that remains from that time.

Comets typically stay far away from the sun, frozen and impossible for us to see. But every once in a while, one will come in toward the sun.

for star charts to help guide you.

The comet appears to burn a bright, lime green color in photographs. But Fraknoi says don't look for something green in the sky.

"The naked eye just shows a fuzzy white glow," he said. "The green only shows up in photographs."

When was this comet last seen on Earth?

Scientists determined that this comet takes about 430 years to orbit the sun.

So the last time it was visible from Earth was in the late 1500s — Galileo Galilei pointed his telescope to the sky .

It will be visible from Earth again in the 2450s.

So if you miss it this time, you'll be waiting a while until your next chance.