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Accurate calculation of eclipses

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#1 ChrisRa

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Posted 29 March 2024 - 03:44 AM

Hi Guys!

 

I have been working for some time to an astronomy project that includes the calculation of the eclipses. I have been using the method of Meeus as it is written in his book Astronomical Algorithms, but the precission is not satisfactory for me. He also gives a more precise method in his book Elements of Solar Eclipses, but I could not find it on internet.

Does any of you have this book and is willing to share it with me in electronic format? I appreciate any help!

Thank you!



#2 timelapser

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Posted 29 March 2024 - 10:15 AM

What would you like to calculate - full curves and general circumstances, or just local contact times and magnitude?  The local circumstances are much easier.  I haven't seen those Meeus references, but the Explanatory Supplement to the Astronomical Almanac does a great job of working through the calculations, if you can find it and know some trig.



#3 ChrisRa

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Posted 29 March 2024 - 04:58 PM

Thank you for your answer. I had a look upon the Explanatory Supplement to the Astronomical Almanac, but is not much of a help. The math formulae I found there were not adapted for numeric computation...



#4 timelapser

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Posted 29 March 2024 - 09:10 PM

If you only want local circumstances it's pretty straightforward: convert your geodetic coordinates to geocentric equatorial (see wikipedia, eg), then rotate to the fundamental frame (trig, in the explanatory supplement), then read off when your distance from the axis matches the umbra or penumbra width.



#5 Cajundaddy

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Posted 24 May 2024 - 10:37 AM

Xavier Jubier has developed incredibly precise and detailed eclipse calcs and linked them to maps for outstanding precision anywhere in the world.  Have a look and see if this is the sort of thing you wish to duplicate on your own.  You could contact him and ask questions about his method but I am not sure if he is interested in collaboration.  Worth a shot.

http://xjubier.free....n/index_en.html





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