APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

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APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by APOD Robot » Tue Dec 29, 2020 5:05 am

Image Earth During a Total Solar Eclipse

Explanation: What does the Earth look like during a total solar eclipse? It appears dark in the region where people see the eclipse, because that's where the shadow of the Moon falls. The shadow spot rapidly shoots across the Earth at nearly 2,000 kilometers per hour, darkening locations in its path -- typically for only a few minutes -- before moving on. The featured video shows the Earth during the total solar eclipse earlier this month. The time-lapse sequence, taken from a geostationary satellite, starts with the Earth below showing night but the sun soon rises at the lower right. Clouds shift as day breaks over the blue planet. Suddenly the circular shadow of the Moon appears on the left and moves rapidly across South America, disappearing on the lower right. The video ends as nightfall begins again. The next total solar eclipse will occur next December -- but be visible only from parts of Antarctica.

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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by zeecatman » Tue Dec 29, 2020 10:04 am

What a great way to portray an eclipse. I'm mesmerized by this geostationary view! I love watching the clouds dance around. Are there any places where one could view longer shots of the Earth from this perspective? Also, is there a reason that even at night, some clouds are brightly lit while others are more predictably dark? (Maybe it's just due to post-processing?)

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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by orin stepanek » Tue Dec 29, 2020 1:13 pm

I liked the clip; but I wish it were slower! It's over before you realize what's going on! :roll:
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by neufer » Tue Dec 29, 2020 2:49 pm

Click to play embedded YouTube video.
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by johnnydeep » Tue Dec 29, 2020 4:38 pm

orin stepanek wrote:
Tue Dec 29, 2020 1:13 pm
I liked the clip; but I wish it were slower! It's over before you realize what's going on! :roll:
Click the gear icon - ⚙️- and change the playback speed to .25. All YouTube videos allow that, as well as speeding them up by up to a factor of 2.
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by johnnydeep » Tue Dec 29, 2020 4:40 pm

zeecatman wrote:
Tue Dec 29, 2020 10:04 am
What a great way to portray an eclipse. I'm mesmerized by this geostationary view! I love watching the clouds dance around. Are there any places where one could view longer shots of the Earth from this perspective? Also, is there a reason that even at night, some clouds are brightly lit while others are more predictably dark? (Maybe it's just due to post-processing?)
Good question. I am also wondering how we can see any detail on the night side of the terminator.
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by orin stepanek » Tue Dec 29, 2020 4:46 pm

johnnydeep wrote:
Tue Dec 29, 2020 4:38 pm
orin stepanek wrote:
Tue Dec 29, 2020 1:13 pm
I liked the clip; but I wish it were slower! It's over before you realize what's going on! :roll:
Click the gear icon - ⚙️- and change the playback speed to .25. All YouTube videos allow that, as well as speeding them up by up to a factor of 2.
Thank you; that was perfect!
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by Chris Peterson » Tue Dec 29, 2020 5:31 pm

johnnydeep wrote:
Tue Dec 29, 2020 4:40 pm
zeecatman wrote:
Tue Dec 29, 2020 10:04 am
What a great way to portray an eclipse. I'm mesmerized by this geostationary view! I love watching the clouds dance around. Are there any places where one could view longer shots of the Earth from this perspective? Also, is there a reason that even at night, some clouds are brightly lit while others are more predictably dark? (Maybe it's just due to post-processing?)
Good question. I am also wondering how we can see any detail on the night side of the terminator.
The imaging instrument covers bands from 450 nm to 13.6 um. It's unclear what bands were used to construct the image, but I think it's pretty clear that some of the IR bands were included.
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by johnnydeep » Tue Dec 29, 2020 5:41 pm

Chris Peterson wrote:
Tue Dec 29, 2020 5:31 pm
johnnydeep wrote:
Tue Dec 29, 2020 4:40 pm
zeecatman wrote:
Tue Dec 29, 2020 10:04 am
What a great way to portray an eclipse. I'm mesmerized by this geostationary view! I love watching the clouds dance around. Are there any places where one could view longer shots of the Earth from this perspective? Also, is there a reason that even at night, some clouds are brightly lit while others are more predictably dark? (Maybe it's just due to post-processing?)
Good question. I am also wondering how we can see any detail on the night side of the terminator.
The imaging instrument covers bands from 450 nm to 13.6 um. It's unclear what bands were used to construct the image, but I think it's pretty clear that some of the IR bands were included.
No doubt you are correct. I found this about GOES (Geostationary Operational Environmental Satellite)- https://www.goes-r.gov/resources/faqs.html
What exactly do GOES detect?
Geostationary weather satellites work by sensing electromagnetic radiation to indicate the presence of clouds, water vapor, and surface features. Unlike ground-based radar systems and some other types of satellites, these satellites do not send energy waves into the atmosphere and analyze returning signals. Rather, GOES work by passively sensing energy. GOES sense visible (reflected sunlight) and infrared (for example, heat energy), from Earth’s surface, clouds, and atmosphere. Earth and the atmosphere emit infrared energy 24 hours a day, and satellites can sense this energy continuously. In contrast, visible imagery is available only during daylight hours when sunlight is reflected.

How do GOES detect this energy?
The instruments on GOES that measure electromagnetic energy are called radiometers. GOES carry two types of imagers: One measures the amount of visible light from the sun that Earth’s surface or clouds reflect back into space. The second measures the infrared energy that Earth’s surface and clouds radiate back to space. Because GOES can sense infrared radiation, they can operate at night.
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by Fred the Cat » Tue Dec 29, 2020 5:56 pm

The real-time view of Earth from L1 is cool. 8-)
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Re: APOD: Earth During a Total Solar Eclipse (2020 Dec 29)

Post by zeecatman » Wed Dec 30, 2020 3:42 am

johnnydeep wrote:
Tue Dec 29, 2020 5:41 pm
Chris Peterson wrote:
Tue Dec 29, 2020 5:31 pm
The imaging instrument covers bands from 450 nm to 13.6 um. It's unclear what bands were used to construct the image, but I think it's pretty clear that some of the IR bands were included.
No doubt you are correct. I found this about GOES (Geostationary Operational Environmental Satellite)- https://www.goes-r.gov/resources/faqs.html
Props to both of you for getting to the bottom of it! Then, I assume the video combines visible and infrared false-colored light, which gives the dark side of the Earth that strange partially-lit look?