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XKCD comic pointing out that that the difference between 91% (or even a 99%) eclipse and a total eclipse is extremely dramatic. An almost total eclipse is barely noticeable, while a total eclipse is a visual phenomenon unlike any other.

https://xkcd.com/2914/
https://www.explainxkcd.com/wiki/index.php/Main_Page
1/n

in reply to AkaSci 🛰️

This is a prediction of how dramatic the total solar eclipse of April 8 will look like if you are lucky or prepared enough to be in the path of totality.
😲
This image is from a website run by Predictive Science Inc, that uses a "Data-Assimilative, Continuously Running Prediction Model" to create these images, which takes the changing magnetic field around the Sun into account in real-time.

The website shows how the eclipse will look like from any location.
https://www.predsci.com/corona/apr2024eclipse/home.php
2/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Cloud-cover forecast from NOAA for Eclipse Day April 8, around 2 PM EDT.

Best places for clear viewing are in northern New England and upstate New York. Also, southern Missouri to central Indiana.

Peak viewing time in Evansville, IN is around 2:00 p.m. CDT (3:00 p.m. EDT).

https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_2.png
3/n

in reply to AkaSci 🛰️

Eclipse chasing, NASA style!

A trio of NASA-funded teams will be chasing the eclipse on April 8, with a bevy of scientific instruments onboard NASA’s WB-57 high-altitude jet planes flying at 470 mph at 50,000 feet, high above the clouds.

Looking forward to their snapshots and videos. And scientific papers.

https://www.youtube.com/watch?v=0xEDe0be6zY
https://science.nasa.gov/solar-system/skywatching/scientists-pursue-the-total-solar-eclipse-with-nasa-jet-planes/
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This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Here are a few pics of one of NASA's WB-57 aircraft.

The WB-57 is a mid-wing, long-range aircraft, developed in the 1960s, originally used by the USAF. The WB-57 can fly for ~6.5 hours, at altitudes exceeding 60,000 feet, has a range of ~2500 miles, and can carry up to 8,800 lbs of payload.

NASA's 3 WB-57s are based at Ellington Field, near Johnson Space Center (JSC) in Houston, as part of their High Altitude Research Program.

https://airbornescience.nasa.gov/aircraft/WB-57_-_JSC
5/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Another high-altitude research aircraft that will be chasing the eclipse and gathering infra-red spectroscopy data will be NSF/NCAR's Gulfstream-V.

Inset below shows Jenna Samra, Smithsonian Astrophysical Observatory scientist, with the Airborne Coronal Emission Surveyor (ACES) instrument onboard the GV.

https://news.ucar.edu/132947/total-eclipse-celestial-wonder-and-scientific-opportunity?sf187561215=1
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This entry was edited (1 month ago)
in reply to AkaSci 🛰️

For those who love to watch planes, here is a video from 2015 with all three of NASA's WB-57 aircraft flying in formation over Houston. This flight was the first time that three WB-57s have been aloft simultaneously since the early 1970s, when the U.S. Air Force had an active squadron of WB-57s.
https://www.youtube.com/watch?v=TvmVTzN8exQ
7/n
in reply to AkaSci 🛰️

Did you know that total eclipses occur more often in the northern hemisphere than the southern one? Or that annular eclipses occur more often at 50°S to 80°S than the equator?

This paper from 1982 shows the frequency of total and annular eclipses, as a function of latitude, between 1700 and 2299 AD. The data is based on calculations at various discrete latitude and longitude points on earth.

See the next post for the explanation.

https://articles.adsabs.harvard.edu/pdf/1982JBAA...92..124M
8/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Total eclipses occur more often in the northern hemisphere than the southern one because -
- Eclipses are more likely in summer, because the Sun is up longer then.
- Summer in the northern hemisphere happens when the Earth is near aphelion, its farthest distance from the Sun for the year, the Sun is a bit smaller in the sky, which favors the occurrence of total solar eclipses and disfavors annular ones.
- The opposite holds for the southern hemisphere.

https://svs.gsfc.nasa.gov/5222
8/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

The following graphic shows a heatmap of the density of total solar eclipse paths over Earth during the 5000-year period between 2,000 BCE and 3,000 CE. Lighter shades mean higher density.

The bias towards the northern hemisphere is clear. The values for longitude points are slightly smeared because the graph has not been corrected for the variance in rotational speed of the Earth.

On average, a given spot on Earth experiences a total eclipse every 366 years.

https://svs.gsfc.nasa.gov/5222
9/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

In addition to the WB-57 aircraft based observations, the NASA Atmospheric Perturbations around Eclipse Path (APEP) campaign will use sounding rockets to study the ionosphere during the eclipse.

3 sounding rockets will be launched from Wallops Island, VA - 45 minutes before, during, and 45 minutes after the peak local eclipse.

4 independent payloads will be deployed by each rocket at 107 km, which will climb to 325 km, taking msmts on the way up and down to 70 km.

https://sites.erau.edu/sail/APEP/
10/n

in reply to AkaSci 🛰️

The NASA APEP mission name takes inspiration from the serpent deity Apep from ancient Egyptian mythology, aka "the Lord of Chaos". Apep is the enemy of the Sun deity Ra and is said to have pursued him and, every so often, nearly consumed him, resulting in an eclipse.

Image below: Ra, in the form of a cat, smiting Apep with a knife. Papyrus of Hunefer, 19th dynasty.

https://sites.erau.edu/sail/APEP/
https://en.wikipedia.org/wiki/Apep
11/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Here is a look at the positions of the Sun and the Moon today, tomorrow and Tuesday, around 3:00 p.m. EDT.

https://www.timeanddate.com/worldclock/sunearth.html?iso=20240407T1504&n=105
12/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Here is the famous painting by space artist Pat Rawlings made in 1989, showing the total solar eclipse of 2017 as seen by humans on the moon.

Well, humans have not set foot on the moon yet since the Apollo missions, but hopefully soon ...

https://twitter.com/Patnspace/status/897632376758685698
http://www.patrawlings.com/default.cfm
13/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

It is E-Day!
Here is the weather forecast and forecast for cloud cover in the path of the total eclipse and the rest of the country.

Please see the rest of this thread for interesting bits of info about this eclipse and eclipses in general.

Happy viewing 😎

14/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

You can follow the progress of the NASA WB-57 aircraft at https://www.flightaware.com/live/flight/N926NA and https://www.flightaware.com/live/flight/NASA927
Tail numbers N926NA and N927NA

N926NA took off from Houston (Ellington Field) at 09:57 CDT, heading SW and is currently just off the Mexican west coast at 50,000 feet altitude. It will soon turn around and track the eclipse.
Similarly for N927NA, which took off from El Paso, TX.

15/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

A real-time pic of the total solar eclipse from the city of Mazatlán on the west coast of Mexico. Also shown is a shot of the pilot aboard the NASA WB-57 aircraft flying at 50,000 feet off the west coast of Mexico, close to Mazatlán!

The 2nd screenshot from NASA webcast shows the scene looking out the window of the WB-57.

😲
Watch the NASA livecast at https://www.youtube.com/watch?v=2MJY_ptQW1o
16/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

These gorgeous views of the total solar eclipse of 2024 were taken from the ground in the city of Torreón in Mexico.

The Baily's beads can be prominently seen in the first pic.

NASA webcast at https://www.youtube.com/watch?v=2MJY_ptQW1o
https://en.wikipedia.org/wiki/Baily%27s_beads
17/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Dallas, a few minutes ago, had this view of the total solar eclipse.
NASA webcast at https://www.youtube.com/watch?v=2MJY_ptQW1o
18/n
in reply to AkaSci 🛰️

Here are a few outstanding pics of the solar eclipse today from NASA.

First, this composite image of multiple exposures over the Washington Monument, by the esteemed NASA photographer Bill Ingalls.

Details and more photos at https://www.flickr.com/photos/nasahqphoto/albums/72177720315879304/
Credit: NASA/Bill Ingalls
19/n

in reply to AkaSci 🛰️

Next, another artistic pic by NASA photographer Bill Ingalls, with the Washington Monument's tip piercing the perfectly positioned partially eclipsed Sun, as seen from Washington D.C.

Details and more photos at https://www.flickr.com/photos/nasahqphoto/albums/72177720315879304/
Credit: NASA/Bill Ingalls
20/n

This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Solar prominences loom large in this awe-inspiring photograph of the solar eclipse taken in Dallas, Texas by NASA photographer Keegan Barber.

Details and more photos at https://www.flickr.com/photos/nasahqphoto/albums/72177720315879304/
Credit: NASA/Keegan Barber
#Eclipse
21/n

in reply to AkaSci 🛰️

Next, the quintessential image of a radiant total solar eclipse, this one from Kerrville, TX, taken by NASA photographer Aubrey Gemignani.

Details and more photos at https://www.flickr.com/photos/nasahqphoto/albums/72177720315879304/
Credit: NASA/Aubrey Gemignani
#Eclipse
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This entry was edited (1 month ago)
in reply to AkaSci 🛰️

The Diamond Ring with Bailey's Beads, shines in this beautiful image of a near-total solar eclipse, taken by NASA photographer Keegan Barber in Dallas, TX.

Details and more photos at https://www.flickr.com/photos/nasahqphoto/albums/72177720315879304/
Credit: NASA/Keegan Barber
#Eclipse
23/n

in reply to AkaSci 🛰️

The Future 🚀 🛰️ 📡

Budding NASA scientists hone their skills at the Kerrville eclipse festival in Kerrville, TX.

Details and more photos at https://www.flickr.com/photos/nasahqphoto/albums/72177720315879304/
Credit: NASA/Aubrey Gemignani
#Eclipse
24/n

in reply to AkaSci 🛰️

One last tidbit of info - the Moon is receding away from earth by about 3.8 cm each year due to tidal interactions (the rate decreases with time). It has been receding from the day it was born, when it was 10x closer.

So, over time, total solar eclipse duration will get shorter and the probability of total eclipses will decrease.

In the distant future, about 0.62 - 1.2 billion years from now, there will be no total solar eclipses, just annular and partial ones.

https://eos.org/features/the-end-of-the-eclipse
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This entry was edited (1 month ago)
in reply to AkaSci 🛰️

Here is a dramatic time-lapse composite image of the total solar eclipse of April 8, which is featured today on the NASA APOD site.

The images were taken by Daniel Korona from the city of Durano in Mexico, halfway between Mazatlán and Torreón.

Baily's beads shine in the near-total eclipse images, as sunlight beams thru gaps in the jagged terrain along the edge of the moon. Solar prominences add a dramatic effect to the images.

Credit: Daniel Korona
https://apod.nasa.gov/apod/ap240412.html
26/n

in reply to AkaSci 🛰️

Some more info on those red filaments seen in many images of the eclipse last Monday.

Those were solar prominences, loops of hot ionized gases which follow the magnetic fields associated with pairs of sunspots and fall back into the photosphere. A typical solar prominence is ~100K km in size. Larger ones can reach 500K km.

Solar flares are more energetic events; they eject material into space, often reaching earth and causing auroras and radio disruption.

https://eclipse2017.nasa.gov/solar-prominences
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This entry was edited (1 month ago)