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.

2022 February 15
The featured image shows a full moon as constructed
by images returned by the Lunar Reconnaissance Orbiter (LRO).
Specifically, the images just to the bright side of the lunar
terminator are used, which shows the lunar surface in great 
Please see the explanation for more detailed information.

Terminator Moon
Image Credit: NASA, Lunar Reconnaissance Orbiter, SVS; Processing & Copyright: Jai & Neil Shet

Explanation: What's different about this Moon? It's the terminators. In the featured image, you can't directly see any terminator -- the line that divides the light of day from the dark of night. That's because the image is a digital composite of 29 near-terminator lunar strips. Terminator regions show the longest and most prominent shadows -- shadows which, by their contrast and length, allow a flat photograph to appear three-dimensional. The original images and data were taken near the Moon by NASA's Lunar Reconnaissance Orbiter. Many of the Moon's craters stand out because of the shadows they all cast to the right. The image shows in graphic detail that the darker regions known as maria are not just darker than the rest of the Moon -- they are flatter.

Dial-A-Moon: Find the phase of the Moon on your birthday.
Tomorrow's picture: eroding sun tower

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