Technical Details of the true-limb Eclipse Path Determination​

Technical Details of the true-limb Eclipse Path Determination

Much interest has been generated by the precise map of the path of the 2024 April 8th Total Solar Eclipse generated by John Irwin, with a big media coverage triggered by the articles by Jamie Carter for Forbes
15 Places In The U.S. That Just Lost Their Total Solar Eclipse — While Texas Gained (


There have been inquiries about the reasons why this map is considered to be precise, especially in the position of the edges of the eclipse path. First of all, it accounts for the topography of both the lunar limb and of Earth and it uses an improved solar radius S equivalent to 959.95″ at 1 a.u. This is a better value to use than the “standard” solar radius S = 959.63″ usually used in eclipse maps. The improved solar radius is backed up by recent determinations collected during solar eclipses, some by us. Secondly it uses the most recent determinations of certain other parameters going into the computation, mainly the Earth’s orientation parameters. In the following table you can find the complete list of parameters.


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