REDEFINING THE SOLAR RADIUS
Besselian Elements Team
Your guide to Solar Eclipses

Eclipse Maps
Display local circumstances computed using the IQP eclipse computational method that accounts for both the lunar limb, observer site topography, and it relies on an improved value for the eclipse solar radius (i.e. 959.95")

Eclipse App
Download our Countdown App to plan and observe your next eclipses powered by the most accurate computational method

Solar Radius Calculation
Read about our misson to determine the best solar radius value for eclipse computations by analyzing the flash spectrum, especially from the path edge. This improves eclipse maps and predictions
Who we are
We are the Besselian Elements Team, passionate eclipse chasers and researchers. We provide accurate eclipse calculations and share our work studying these awe-inspiring phenomena
The Eclipse Countdown App Is Now Available on the App Store and Google Play
May 1, 2026
We’re excited to announce the official launch of Eclipse Countdown app, now available on both the App Store and Google Play. This app was born ...
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Besselian Elements Collaboration with Eclipsefan
August 3, 2026
At Besselian Elements, our focus has always been the “science of the shadow”, providing the most rigorous data possible by accounting for the real lunar ...
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A live Weather page in our Eclipse Countdown App
July 29, 2026
New in the app: a live Weather page for the August 12, 2026 eclipse in Spain With few days left before the total solar eclipse ...
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The IQP Engine Inside TotalControl: Precision Timing for Eclipse Photography
July 15, 2026
From Leuven to Spain: how our collaboration with TotalControl began In June 2025 we found ourselves in Leuven, Belgium, for the Solar Eclipse Conference hosted ...
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Eclipse predictions need to be periodically updated
July 4, 2026
Eclipse predictions are based on several inputs: the position of Sun, Moon and Earth, the topography of the lunar limb, the topography of Earth’s surface, ...
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Eclipse Limits and Centreline are jagged lines
June 12, 2026
The eclipse limits of the umbral shadow path of a total solar eclipse are traditionally depicted as smooth lines on a map. Inspection of our ...
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2026 Solar Eclipse in Spain: Real Sky Conditions from Weather Webcams
April 21, 2026
The solar eclipse next year will be visible from Spain around 8:30 pm local time—very close to sunset. That means the Sun will be low, ...
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Average cloud cover over Spain considering cloud shadows
March 21, 2026
https://view.eumetsat.int/ Jul 31 18:10 UTC Eumetview Weather is always a critical factor when observing a total solar eclipse. For the August 12, 2026 eclipse in ...
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Which clouds can ruin your eclipse view
August 26, 2025
When observing a low-altitude solar eclipse, like the one that will occur in Spain on August 12, 2026, it is possible for distant clouds to ...
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