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[Music throughout] A coronagraph is

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a way to see distant planets hidden by the glare of the star they orbit.

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The coronagraph reduces the light coming directly from the star to separate it from

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the light reflected by the planet. WFIRST

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doesn’t block the star’s light with an opaque disk as a simple coronagraph might.

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Instead, it uses a combination of disks with complex

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patterns and light-blocking stops to create destructive interference

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with the star’s light, effectively making it disappear,

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while allowing the light from planets to pass through.

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A complicating factor is that the light picks up small distortions as it reflects off the

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telescope’s series of mirrors, and these distortions can reduce the effectiveness

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of the destructive interference. Collecting more light

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increases the image signal, but the planets are still hidden under blobs of leftover

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distorted starlight. To remove these blobs, the

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coronagraph has special deformable mirrors that can change shape by using

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hundreds of tiny pistons. This corrects distortions in the light beam.

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As the mirrors deform, the blobs of light slowly begin to

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disappear, revealing brighter planets. Further adjustment

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brings fainter planets into view. Advanced software

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processes this data, further improving the contrast and clarity of the

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image. This processing makes objects more than a billion times

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fainter than the star visible. As a result,

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WFIRST will provide the first look at individual planets in star systems

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that might be similar to our own.

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[Explore: Solar system & beyond]

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[NASA]