Short: Display ephemerides for all the planets Author: ecdowney@noao.edu (Elwood Downey), Amiga port by uploader Uploader: haubi geocities com (Stefan Haubenthal) Type: misc/sci Version: 4.28 rel. 2 Architecture: m68k-amigaos Ephem is a program that displays ephemerides for all the planets plus any two additional objects. The additional objects may be fixed or specified via heliocentric elliptical, hyperbolic or parabolic orbital elements to accommodate solar system objects such as asteroids or comets. Information displayed about each object includes RA and Dec precessed to any epoch, local azimuth and altitude, heliocentric coordinates, distance from sun and earth, solar elongation, angular size, visual magnitude, illumination percentage, local rise, transit and set times, length of time up, constellation, and angular separations between all combinations of objects. A special detail of Jupiter's moons and central meridian longitude is also available. Observing circumstance information includes UTC and local date and time, local sidereal time, times of astronomical twilight, length of day and night, local temperature, pressure and height above sea level for the refraction model and a monthly calendar. RA/Dec calculations are geocentric and include the effects of light travel time, nutation, aberration and precession. Alt/az and rise/set/transit and, optionally, angular separation calculations are topocentric and include the additional effects of parallax and refraction. Plot and listing files of selected field values may be generated as the program runs. The plot files are full precision floating point values in ASCII intended for export to other plotting programs. The listing files are tables formatted for more general human reading. Ephem includes simple quick-look facilities to view these files. One may watch the sky or the solar system with a simple character-oriented screen display. Ephem may be asked to search for interesting conditions automatically, using several algorithms. Most fields displayed on the screen may be used as terms in an arbitrary arithmetic expression that can be solved for local zero or extrema, or the time of state change of any boolean expression can be found. The program is some 11,000 lines of C. It uses only a very simple set of io routines and should be easily ported to any 24x80 ASCII display. To date, it has been ported to several flavors of Unix, VMS, MS-DOS and, simplistically, the Macintosh using Think-C.