Program Description

Alcyone Ephemeris is an accurate and fast astronomical ephemeris calculator covering the period 3000 BC to AD 3000. It calculates heliocentric, geocentric, and topocentric positions of the Sun (Earth), Moon, planets and fixed stars in ecliptical, equatorial, and horizontal coordinates (including angular differences between two bodies), with optional corrections for parallax and refraction; rectangular coordinates, velocity, apparent diameter, magnitude, phase, lunar libration, orbital elements, differences for all of these, and more. In addition Alcyone Ephemeris offers a wealth of functionality: plotting ephemeris data, searching for specific values, scripting to write programs for more complex computations, saving as HTML or Excel files to export output to spreadsheets, word processors and web pages, and printing. The ephemeris calculation is based upon Steve Moshier's analytical ephemeris using trigonometric expansions for the earth and planets and the lunar ephemeris ELP2000-85 of Chapront-Touzé and Chapront for the moon, both adjusted to Jet Propulsion Laboratory's DE404 . There are further adjustments in Alcyone Ephemeris, some optional, to JPL's more recent DE406, the most accurate long-term ephemeris. Alcyone Ephemeris is fast. With an Athlon XP 2000+ processor, 100 calculations of geocentric longitude, latitude, and distance for the sun, moon, and all planets take about 2 seconds. The ephemeris program itself is also compact, about 20 mgb, compared to nearly 200 mgb of data files for DE406. A comprehensive documentation includes tabular and graphic comparisons of calculations with HORIZONS epehemris genarator.