Template:Zodiac date/doc

Usage
This template calculates duration of the specified tropical sign for the current year (2024), UTC. The sine term accounts for the eccentricity of the Earth's orbit. Accuracy about 1-2 hours.

The template has one unnamed parameter. Values for the parameter are as follows:

Accuracy
Internally the template uses an empirical formula to calculate when the Sun has begun its orbit at the first point of Aries, made 1/12 of a rotation in ecliptic longitude, 2/12 of a revolution, etc. In other words, it finds the Julian date when the ecliptic longitude of the Sun is 0°, 30°, and so on up to 330°. When these Julian dates are substituted into a formula available on page C5 of the Astronomical Almanac for the Year 2011 for the years 2009, and 2012–2016 to find the longitude of the Sun, the greatest error is 0.076°, which is around 1.9 hours.