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Astronomy Picture of the Day - The Sky in 2021
APOD.NASA.gov ^ | 21 Mar, 2022 | Image Credit & Copyright: Cees Bassa (Netherlands Institute for Radio Astronomy)

Posted on 03/21/2022 3:14:05 PM PDT by MtnClimber

Explanation: What if you could see the entire sky -- all at once -- for an entire year? That, very nearly, is what is pictured here. Every 15 minutes during 2021, an all-sky camera took an image of the sky over the Netherlands. Central columns from these images were then aligned and combined to create the featured keogram, with January at the top, December at the bottom, and the middle of the night running vertically just left of center. What do we see? Most obviously, the daytime sky is mostly blue, while the nighttime sky is mostly black. The twelve light bands crossing the night sky are caused by the glow of the Moon. The thinnest part of the black hourglass shape occurs during the summer solstice when days are the longest, while the thickest part occurs at the winter solstice. Yesterday was an equinox -- when night and day were equal -- and the northern-spring equinox from one year ago can actually be located in the keogram -- about three-quarters of the way up.


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: nasa
To be added or removed from the Astronomy Picture of the Day ping list please send me a request via "Private Reply" (Mail).

For more detail go to the link and click on the image for a high definition image. You can then move the magnifying glass cursor then click to zoom in and click again to zoom out. When zoomed in you can scan by moving the side bars on the bottom and right side of the image.

1 posted on 03/21/2022 3:14:05 PM PDT by MtnClimber
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To: MtnClimber

2 posted on 03/21/2022 3:14:25 PM PDT by MtnClimber (For photos of Colorado scenery and wildlife, click on mycreen name for my FR home page.)
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To: 21stCenturion; 21twelve; 4everontheRight; abb; AFB-XYZ; AFPhys; America_Right; AZ .44 MAG; ...
Pinging the APOD list.

🪐 🌟 🌌 🍔


3 posted on 03/21/2022 3:14:59 PM PDT by MtnClimber (For photos of Colorado scenery and wildlife, click on mycreen name for my FR home page.)
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To: MtnClimber

“What do we see” is a cat.


4 posted on 03/21/2022 3:20:45 PM PDT by Repeal The 17th (Get out of the matrix and get a real life.)
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To: Repeal The 17th

Tucker Carlson’s bowtie


5 posted on 03/21/2022 3:37:05 PM PDT by wxgesr (I wanna be the first person to surf on another planet....)
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To: MtnClimber

6 posted on 03/22/2022 5:15:06 AM PDT by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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