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APOD

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.

A Lunar Corona with Jupiter and Saturn

Explanation: Why does a cloudy moon sometimes appear colorful? The effect , called a lunar corona , is created by the quantum mechanical diffraction of light around individual, similarly-sized water droplets in an intervening but mostly-transparent cloud. Since light of different colors has different wavelengths , each color diffracts differently. Lunar Coronae are one of the few quantum mechanical color effects that can be easily seen with the unaided eye. Solar corona e are also sometimes evident. The featured composite image was captured a few days before the close Great Conjunction between Saturn and Jupiter last month . In the foreground, the Italian village of Pieve di Cadore is visible in front of the Sfornioi Mountains.

New: APOD is now available in Taiwanese from National Central University

Date January 19, 2021
Credit Image Credit & Copyright: Alessandra Masi
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.