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.

2024 September 3
The featured image shows an orange sunset sky
with clouds across the bottom and several bright stars
near the top center. Just at the top of the cloud deck 
on the left is a half-lit Moon. 
Please see the explanation for more detailed information.

Quarter Moon and Sister Stars
Image Credit & Copyright: Alan Dyer, TWAN

Explanation: Nine days ago, two quite different sky icons were imaged rising together. Specifically, Earth's Moon shared the western sky with the sister stars of the Pleiades cluster, as viewed from Alberta, Canada. Astronomical images of the well-known Pleiades often show the star cluster's alluring blue reflection nebulas, but here they are washed-out by the orange sunset sky. The half-lit Moon, known as a quarter moon, is overexposed, although the outline of the dim lunar night side can be seen by illuminating earthshine, light first reflected from the Earth. The featured image is a composite of eight successive exposures with brightnesses adjusted to match what the human eye would see. The Moon passes nearly -- or directly -- in front of the Pleaides once a month.

Tomorrow's picture: open space


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