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Hello to all,

and in particular to Lars, Paul, Jim and Frank,

Thank you Lars for your historical impressive and active knowledge. Therefore, for Eclipse Island, their late 18th Century Latitude determination differs by less than 5" from our modern value. Its 18th Century Longitude determination differs by less than 20" (or 0.23 NM at latitude N46°) from such modern value. I keep thinking that this is truly remarkable for their epoch, especially for their Longitude determination.

As regards the Sun SD difference, the table V value at 15'52" differs by 5.43" from the value I have been using. Hence with the 1766 SD at 15'52" the beginning of the Eclipse happens 16s earlier, and it ends 13 s later. These time differences are consistent with the fact that during the very last minute before the Eclipse (just before 1st contact), the Limbs refracted distance decreased by 19" and over the first minute just after the end of the Eclipse (just after last contact) the Limbs refracted distance increased by 24". As earlier mentioned, such "closure" rates just before and just after the Eclipse itself can hardly be considered as "locally linear" functions of elapsed time, even over such small elapsed time durations barely exceeding 15 seconds of time, here with 16s before and 13s later.

To you Paul, thank you for your numerical checks on the environment of this eclipse which took place on Aug 5th, 1766 (and my apologies for the earlier typo on the date indicated in the ending remark of my last post).

Finally, Jim, yes you interpreted correctly my query about the Greenwich Longitude of Eclipse Island.

Thanks to you all, including Frank E. Reed of course for "hosting" us. Through clever editing of this late 18th Century document, you made our studies possible on this quite interesting topic submitted by Jim.

Kermit