U.S. Naval Observatory’s
Interactive Computer Ephemeris

The 4 files below constitute version 0.51 of the U.S. Naval Observatory’s “Interactive Computer Ephemeris”, which replaces the yearly programs called the Floppy Almanac. Operationally, ICE is identical to the FA series, except that there are a number of data files, each covering part of the range of dates.  Main program, data for 1979-2001  Aux. catalogs, data for 2110-2049  Data for 1801-1902  Data for 1902-1979

Only the first is needed for the years indicated. Other disks contain only the additional data files, and require the first disk. Disk 2 has the catalog files (Messier catalog, etc) that were part of the FAnn series; the files are identical to the older versions, so if you have built a special catalog, it can be used directly with ICE.

The program covers nearly all that is given in the yearly “Astronomical Almanac” published by USNO. Positions of planets; rotational and illum- ination data; sun/moon/planet rise, transit, and set times. It does not include the satellite (moon) data for other planets; the latter IS included in the book. The output is a simple numerical tabulation, no graphics. Accuracy is equivalent to the book, that is, world-class accuracy. Output may be directed to a file for later use.

A more recent program called MICA (Multi-year Interactive Computer Alamanac) is intended to replace ICE. MICA also runs on the Macintosh. However, MICA is good for only 1990 – 2000, whereas ICE covers 1801 to 2049. And, unlike ICE, MICA is not free.

ICE is no longer supported by USNO.

Bill Arnett; last updated: 2000 Jan 20