

A072235


Years of recorded observations of Comet Halley.


1



240, 164, 87, 12, 66, 141, 218, 295, 374, 451, 530, 607, 684, 760, 837, 912, 989, 1066, 1145, 1222, 1301, 1378, 1456, 1531, 1607, 1682, 1759, 1835, 1910, 1986
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refs;
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text;
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OFFSET

1,1


COMMENTS

This sequence is not welldefined for many reasons (negative years are illdefined; calendars change often, so when does a year begin?; what does "observed" mean?; what if the comet was observed both at the end of one year and at the beginning of another, as in 1985/1986?; etc.).  N. J. A. Sloane, Jun 24 2007
The first four terms given are years B.C., others are A.D. I do not know if these years necessarily coincide with actual years of perihelion. Some sources and these numbers indicate that the comet's period varies. These years are taken directly from the U.S. National Air and Space Museum link.


LINKS

Table of n, a(n) for n=1..30.
National Air and Space Museum, Exploring Comets  Historical Records
N.A.S.A., Comet Fact Sheet
Wikipedia, Comet Halley


CROSSREFS

See A100748 for another version.
Sequence in context: A078151 A278179 A100748 * A298453 A121378 A191533
Adjacent sequences: A072232 A072233 A072234 * A072236 A072237 A072238


KEYWORD

sign


AUTHOR

Rick L. Shepherd, Jul 05 2002


STATUS

approved



