REDEFINING THE SOLAR RADIUS

Besselian Elements Team

Your guide to Solar Eclipses

eclipse_map

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

chromosphere

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

Overhead view of a diverse team discussing around a wooden table, using technology.

The Eclipse Countdown App Is Now Available on the App Store and Google Play

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

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

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

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

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

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

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

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

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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Publications

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