Comparison of Baily Beads Analysis in Occult 4 by David Herald and the predictions by the Besselian Elements team/John Irwin in JOA2024_4.pdf
following up SEML msg #33125 Oct. 09 2024
https://groups.io/g/SEML/message/33125
An
article we wrote on experimentally assessing eclipse maps accuracy has
recently been published in the Journal for Occultation Astronomy:
https://iota-es.de/JOA/JOA2024_4.pdf
Few
months ago we started a discussion on SEML about the subject: the
article presents further experimental data and it provides a more
thorough analysis of the matter. We hope it will contribute to the
appreciation of the subtle art of eclipse predictions and mapping.
Kind Regards, Luca Quaglia on behalf of the Besselian Elements Team
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| Figure5 on pg 6 JOA2024_4.pdf |
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| Occult limbplot for C2 |
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| Occult limbplot for C3 |
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| Screenshot Occult for C2 |
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| Screenshot Occult for C3 |
An insightful discussion of the TSE2024 in the northern graze zone - that paper is also most valuable in the comparison of various eclipse prediction/simulation tools.
How does Occult 4 fit in here?
I cross-checked the predictions by John Irvin of the Besselian Elements team using the paramaters given for the Stephenville, TX site and the published "eclipse solar radius" r=959.95".
I get 14 sec for the duration of totality within the accuracy of reading the graph to the nearest half-second which is essentially identical to 13.7 s in JOA2024_4.pdf.
The contact times C2 and C3 are approx. 1 sec earlier in Occult: C2=18:39:05.5, C3=18:39:19.5. than reported (18:39:06.6 and 18:39:20.3).
First of all this is quite comforting for users of Occult.
What might be the reason for the offset of 1 sec in time?
Occult uses the ephemeris DE435 while Besselian Elements/John Irwin use DE440, there might be other causes.
BTW it is essential to use the latest EOP (Earth orientation) parameters in Occult.
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