Polar Precession / Polar Obliquity Calculator

A spreadsheet program that Paul LaViolette has written for use with Microsoft Excel®.

Calculates the ecliptic longitude position of the vernal equinox for arbitrary dates in the past.

It also calculates the corresponding angle of polar obliquity (the inclination of the Earth’s pole to the ecliptic).

The program uses a mathematical expansion taken from astrometer Andre Berger’s 1977 and 1978 publications.

After a three day trial period please remit $10 via PayPal box below.

New York residents will be charged 8.25% sales tax.

$10 shareware download

Windows version: precess.xls (File size: 20 kB)

(Windows: To save to hard disk right click on file name. Then click on “save target as” and select destination.)

Mac version: precess (File size: 14 kB)