5cd0e60d74
Astronomy Engine used to use USNO historical and predictive tables, along with linear interpolation, to calculate Delta-T values. The problem with the USNO tables is, they did not work well outside a few centuries around present day. Later I replaced with Espenak & Meeus piecewise polynomials that work over a much larger time span (thousands of years). I just discovered there were still comments in the code referring to the USNO models. I updated the ones I could find to reflect the current truth about how the code works today.
Astronomy Engine examples in Python
Culmination
Finds when the Sun, Moon, and planets reach their highest position in the sky on a given date, as seen by an observer at a specified location on the Earth. Culmination is also the moment a body crosses the meridian, the imaginary semicircle in the sky that passes from due north on the horizon, through the zenith (straight up), and then toward due south on the horizon.
Horizon Intersection
This is a more advanced example. It shows how to use coordinate transforms to find where the ecliptic intersects with an observer's horizon at a given date and time.
Lunar Eclipse
Calculates details about the first 10 partial/total lunar eclipses after the given date and time.
Moon Phase Calculator
This example shows how to determine the Moon's current phase, and how to predict when the next few quarter phases will occur.
Positions
Calculates equatorial and horizontal coordinates of the Sun, Moon, and planets.
Rise/Set
Shows how to calculate sunrise, sunset, moonrise, and moonset times.
Seasons
Calculates the equinoxes and solstices for a given calendar year.
API Reference
Complete documentation for all the functions and types available in the Python version of Astronomy Engine.