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by U.S. Naval Observatory, 124+ Page Hardbound Manual,
Includes CD-ROM with PC (Windows) Software,

MICA does not support Mac 64-bit operating systems, see notice below.

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About MICA, The Multiyear Interactive Computer Almanac 1800-2050

The Multiyear Interactive Computer Almanac (MICA Version 2.2.2 ) is a software system that runs on modern versions of Windows computers created by the U.S. Naval Observatory's Astronomical Applications Department, especially for astronomers, surveyors, meteorologists, navigators and others who regularly need accurate information on the positions, motions, and phenomena of celestial objects. MICA produces high-precision astronomical data in tabular form, tailored for the times and locations specified by the user. Unlike traditional almanacs, MICA computes these data in real time, eliminating the need for table look-ups and additional hand calculations. MICA tables can be saved as standard text files, enabling their use in other applications. Several important new features have been added to this edition of MICA, including: extended date coverage from 1800 to 2050; a redesigned user interface; a graphical sky map; a phenomena calculator (eclipses, transits, equinoxes, solstices, conjunctions, oppositions, elongations), ephemerides of Jupiter's Galilean satellites and selected asteroids; the JPL DE405 lunar and planetary ephemerides; and updated catalogs of celestial objects, including a new astrometric catalog containing about 230,000 stars.

Notice Regarding the Mac Edition of MICA
July 2018

Apple has announced that "all future Mac software will eventually be required to be 64-bit" (see More specifically, Apple announced at its 2018 Worldwide Developers Conference that macOS 10.14 Mojave will be the last version of macOS to support 32-bit applications. MICA for Macintosh is a 32-bit application. USNO regrets that it will not be producing a 64-bit version of MICA for Macintosh, and thus will cease development work on the product effective immediately. MICA for Mac 2.2.2 stands as the final version of the product. MICA runs successfully on macOS versions through 10.13, although a workaround procedure (here) is required for installing the product under the most recent versions of macOS. USNO will continue to provide technical support for MICA for Mac running on Intel-based Macs and macOS versions through 10.13. Potential buyers of MICA should take this into account before purchasing the product.

MICA for Windows will continue to be developed and supported. Mac users may be able to run MICA for Windows in Boot Camp or within a Windows virtual machine, although this has not been fully tested in all virtual environments.

Owners of Version 2.0 can find the latest updates here.

MICA performs the following types of computations—Click on underlined text for more info:

  • Precise positions for the Sun, Moon, major planets, selected asteroids, selected bright stars, and star-like cataloged objects (e.g. stars, quasars, galaxies, etc.) using external catalogs provided with the program. Ten different position types are available. Output is in the form of ASCII tables and the accuracy varies by calculation.
  • Various astronomical time and reference system quantities (e.g. sidereal time, nutation and obliquity, equation of the equinoxes, calendar/Julian date conversions, and Delta T).
  • Twilight, rise, set, and transit times for major solar system bodies, selected bright stars, selected asteroids and cataloged objects.
  • Physical ephemerides useful for making observations of the Sun, Moon, and major planets. Both illumination and rotation parameters are available.
  • Low-precision topocentric data describing the configuration of the Sun, Moon, major planets, and selected asteroids at specified times and locations. MICA Version 2.0 also includes a sky map option as an aid in locating the objects.
  • Solar and lunar eclipse and transits of Mercury and Venus visibility information.
  • Positions of Jupiter's Galilean satellites, and offsets of the satellites from Jupiter.
  • Dates and circumstances of various astronomical phenomena (solstices and equinoxes, Moon phases, conjunctions, oppositions, and greatest elongations of Mercury and Venus). A phenomena search feature is also available which generates a table similar to the ‘Diary of Phenomena’ tables contained in section A of The Astronomical Almanac.

Computer System Information

MICA Version 2.0 has been designed for modern computers running the Microsoft Windows® and Apple Macintosh® computer running Mac OS X 10.3.9 or higher. MICA no longer operates under the Classic (OS 9) Environment. The distribution CD-ROM contains both the PC and Mac editions of MICA.

Minimum System Requirements:

  • PC-compatible 200 MHz Pentium or higher
  • Windows® XP, Vista, 7, 8 or 10 operating system
  • Internet Explorer version 4.0 (5.0 recommended)
  • 64 MB of RAM
  • 135 MB of hard disk space (1 MB on the C: drive)
  • CD-ROM drive for installation
  • VGA or higher-resolution monitor (with screen area set to at least 640 x 480 pixels and 256 colors)

About the Cover Photograph

A beautiful sunrise over the ocean is punctuated by the transit of Venus in June, 2004. This image was taken by Jeff Ball with a Canon 10D at ISO 200 using a 70-200-mm zoom lens and a Canon 2X converter at 1/760-second at f /5.6.