Talk at the Jewish Calendar Seminar on
Wednesday, 18 Kislev (Dec. 1), 4-5 pm

Speaker: Dr. Roy Hoffman (Hebrew University)

Title:
"Rational Design of Lunar Visibility Criteria"

Abstract
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A wide variety of criteria have been proposed over thousands of years to
predict the visibility of the New Moon. Here, a rational approach to the
evaluation of criteria is proposed. An ease of visibility parameter is
derived and adjusted to zero at the limit where visibility becomes possible.
The time of first appearance is correlated to this parameter. The criteria
considered here perform about as well as each other except for those based
on the time since conjunction.