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MenoData / Time4J

Advanced date, time and interval library for Java with sun/moon-astronomy and calendars like Chinese, Coptic, Ethiopian, French Republican, Hebrew, Hijri, Historic Christian, Indian National, Japanese, Julian, Korean, Minguo, Persian, Thai, Vietnamese
GNU Lesser General Public License v2.1
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Incorrect sign in last term of calculation of mean lunar anomaly? #891

Closed maventis closed 4 years ago

maventis commented 4 years ago

Hello,

Please correct me if I am wrong, but I understood from Meeus 2nd Ed. (1998) that the last term of this line (474 in file MoonPhase.java) should not be positive, but instead negative:

Currently it is this:

double meanAnomalyMoon =
134.9633964 + (477198.8675055 + (0.0087414 + ((1.0 / 69699) + (1.0 / 14712000) * jct) * jct) * jct) * jct;

I believe it should be corrected to this:

double meanAnomalyMoon =
134.9633964 + (477198.8675055 + (0.0087414 + ((1.0 / 69699) - (1.0 / 14712000) * jct) * jct) * jct) * jct;
MenoData commented 4 years ago

Thank you very much for having found this typo in calculation. I will correct it as soon as possible..

MenoData commented 4 years ago

Small note: The calculation error is very small, however, so nobody needs to worry about it.