Universe Today reports Princeton Team Directly Observes Planets Around Nearby Stars
CHARIS allows astronomers to isolate light reflecting from planets. That’s difficult to do, since they are so much dimmer than the stars they orbit. CHARIS is able to isolate the reflective light from planets larger than Jupiter. Then astronomers can analyze that light to learn about the planet’s age, atmospheric composition, and its size."
The spectrograph sits inside a 500 lb case that measures 30x30x12. Inside that case, it’s kept at –223.15 Celsius (50 Kelvin, –369 F.) The CHARIS instrument has nine mirrors, five filters, two prism assemblies and a microlens array. The microlens array is a special optical device with an array of tiny lenses etched into its surface.
CHARIS is designed to capture the light from distant exoplanets, so its field of view is tiny. It’s only 2 arc-seconds, which is a tiny patch of sky. For reference, the full Moon is about 1,800 arc-seconds. But it can take images across a wide band of light wavelengths. The fact that it captures such a wide band of light is what allows such detailed analysis of anything it’s pointed at.