Planet Hunting Techniques: Direct Imaging

Taking a picture of an extrasolar planet sounds like the easiest way to discover a planet, but in reality, it is probably the most difficult. Seeing the faint glow of a planet amidst the brilliant glare of its parent star is like spying a firefly buzzing around a huge spotlight from a mile away.

But it has been done. Astronomers use a dark “mask” called a coronagraph to cover up the star and most of its glare. If the planet is far enough away from its star so that it isn’t also covered by the coronagraph, a keen-eyed telescope might be able to pick out the dim reflected light of the planet shining through.