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Solar Eclipses and Totality

IN THE DISTANT PAST, the Moon was much closer to the Earth. Thanks to tidal forces and the Law of Conservation of Momentum, the size of the Moon’s orbit has been increasing (currently by ~3.8 cm/yr).1 As luck would have it, we live in an epoch in which the Moon has an apparent size close to that of the Sun. When near perigee, the moon’s apparent size is adequate to completely cover the Sun. (Unfortunately we do not get monthly eclipses because the Moon’s orbit is tilted about 5° with respect to the ecliptic.)

Very Rare Superoutburst of PR Herculis

Winchester Observatory has monitored hundreds of variable stars with an automated imaging system over the last nine years. Most are run of the mill long period variables (mainly Mira-type stars) that vary slowly and somewhat predictably; the rest are the much more exciting cataclysmic variables (CVs)--stars that undergo sudden and dramatic increases in brightness.

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Today in History

2001Comet Petriew discovered at SSSP.16 years ago

Today is Fri 18 Aug 2017, JD 2,457,984 (day 230 of 365 this year).

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