I found this NASA website which says that to predict eclipse, we should solve the Besselian elements ..what does this mean, how can I solve for Besselian elements? Is there a numerical method? I need to find the circumstance (length of eclipse etc) at a given coordinate..Sorry I am very new to astronomy so my question might be basic.. see the picture below

  • $\begingroup$ Are you looking at this for a particular, known eclipse? Looks like your details are for the July 2nd Total Solar eclipse, which case, the NASA website has an interactive tool for finding durations at particular locations. The one for the eclipse in question is at eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/…, and you can click on coordinates in the eclipse path to pull durations. $\endgroup$ – notovny Jun 10 '19 at 15:50
  • $\begingroup$ So is your question "what is the definition of Besselian elements of [something]"? I get the feeling you need to read the entire site -- and BTW please post a link to that specific NASA page so we can evaluate what's going on there. $\endgroup$ – Carl Witthoft Jun 10 '19 at 17:26
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    $\begingroup$ Looks like it's this NASA page. I would imagine Jean Meeus's Astronomical Algorithms book would have info on using Besselian elements to calculate eclipse circumstances; unfortunately my copy is at work and not to hand $\endgroup$ – astrosnapper Jun 11 '19 at 3:56