Saros Series (5)
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This article is the most extensive and most detailed of those I have researched, and contains within it an answer to just about every question you might have about Saros Series (I hope!). Little of the information is available elsewhere (as far as I am aware), so I hope it will become a definitive text on the subject. The article starts by describing the various circumstances which must come together to produce very similar eclipses, as sequences of such eclipses are what constitute a Saros Series. The variabilities in the numbers of eclipses between different Saros Series are then described, before a reason for this variability in terms of the calendar date of the eclipses is given. I then explore the reason for this calendar-date dependency before showing how this is caused, and how changes in the calendar date of the first eclipse of a Series can have a dramatic influence on the number and distribution of eclipses in a Series. Longer-term changes are then discussed, caused by variations in both the Moon's orbit and of that of the Earth, before the consequences of the eccentric orbit of the Moon are considered. This firstly leads to the important result that there are actually three sets of Series to be considered, not just the overall ensemble. A very specific effect is then described in some detail - the "apogee/perigee effect" - which is shown to be responsible for some otherwise puzzling characteristics of the Saros Series variability. Finally, the "Big Question" is answered - why does the periodicity of the variations have the value it does? - before a Grand Finale draws all the work together. Click on the title to read the article. |
