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
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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Publications
