MICA Software for PCs and Macs
(Current Version: Version 2.2.2, January 2012)
An easy-to-use astronomical almanac from the U.S. Naval Observatory
MICA, the Multiyear Interactive Computer Almanac, is a software system that provides high-precision astronomical data in tabular form for a wide variety of celestial objects. The program computes many of the astronomical quantities tabulated in the The Astronomical Almanac. However, MICA can compute this information for specific locations and flexible times, thus eliminating the need for table look-ups and additional hand calculations.
Designed primarily for professional applications, MICA is intended for intermediate-to-advanced users. Basic knowledge of astronomical terminology and positional astronomy is assumed.
MICA provides essential data for use in
|Astronomy and astrophysics||Space science||Geodesy and surveying|
|Operations planning||Accident reconstruction and litigation||Illumination engineering|
MICA was first released in 1993 for MS-DOS and Apple Macintosh systems. MICA 2.0 was updated for Windows and modern Apple Macintosh systems and released in August 2005. MICA 2.0 provided all the data available in earlier versions of the software and included several new features. The current version of MICA is 2.2.2, which was released in January 2012.
MICA can perform the following types of computations:
- Precise positions for the Sun, Moon, major planets, Pluto, selected asteroids, selected bright stars, and cataloged objects (e.g. stars, quasars, galaxies, etc.) using external catalogs provided with the program. Up to ten different position types are available (depending on which object was chosen).
- Various astronomical time and reference system quantities (e.g. sidereal time, nutation and obliquity, equation of the equinoxes, Earth Rotation Angle, 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, major planets, and Pluto. Both illumination and rotation parameters are available for all listed bodies, except for the Sun.
- Low-precision topocentric data describing the configuration of the Sun, Moon, major planets, Pluto, and selected asteroids at specified times and locations. MICA also includes a sky map option as an aid in locating the objects.
- Visibility information for solar and lunar eclipses, as well as transits of Mercury and Venus.
- Four different types of positions of Jupiter and the Galilean Satellites and offsets of the satellites from Jupiter.
- Dates and circumstances of various astronomical phenomena (solstices and equinoxes, apsides of Earth and the Moon, 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' contained in section A of The Astronomical Almanac.
New features and changes in MICA 2.2/2.2.1/2.2.2 include
- Earth Rotation Angle (ERA) and the equation of the origins.
- Apside times (perigee/apogee of the Moon, perihelion/aphelion of Earth) as a stand alone computation or within the Phenomena Search function.
- The DeltaT.val file has been updated with new data. The date with the first predicted value for this file is 2455745.0 (2011 July 2 12:00).
- Computations of future eclipses and transits now allow the user to set their own value of delta T.
- Configurations of major solar system bodies and asteroids, lunar eclipses, and all phenomena calculations now include "Zone" as a time system option.
- Magnitudes have been added to the positional information provided for solar system bodies and catalog stars.
- The International Astronomical Union (IAU) 2000B nutation model was replaced with the 2000K nutation model described in USNO Circular 181, Nutation Series Evaluation in NOVAS 3.0 (Kaplan 2009).
- Lunar distance has been added to the "Phases of the Moon" output table.
- Physical ephemeris algorithms have been updated to account for the aberration of the Sun due to the planet's motion.
- Physical ephemeris calculations have been updated with data from the "Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2006."
- The 'Planet' column header in the solar conjunctions output has been renamed to 'Object' to cover both planets and asteroids.
MICA Windows sample screens (Windows 7):
MICA Mac sample screens (Mac OS X):
Minimum system requirements for Windows edition:
- 200 MHz Pentium or higher processor
- Windows® 98, Millennium Edition, NT® 4.0 (with Service Pack 4 or later), 2000, XP, Vista, or Windows 7 operating system
- Internet Explorer version 5.0 or later
- 64 MB of RAM (128 MB recommended)
- 135 MB of hard disk space (848 KB 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)
Minimum system requirements for Mac OS edition:
- Macintosh computer running Mac OS X 10.3.9 or higher. MICA no longer operates under the Classic (OS 9) Environment.
- 250 MB of hard disk space
"Delta T" File Updates
For highest accuracy, the supplied file of delta T values should be updated periodically. Delta T is the difference between Terrestrial Time (TT) and Universal Time (UT1). For information about the most recent delta T file, see
Version 2.2.2 is the current version of MICA. It was released in January 2012 and is valid for years 1800 through 2050. This version includes several corrections and revisions to the 2.2.1 version released in April 2010 along with a few new features. See the ReadMe file for further information.
Frequently Asked Questions and Software Bug Reports
MICA is published for the U.S. Naval Observatory by Willmann-Bell, Inc. Both Windows and Macintosh editions of the software are distributed on a single CD-ROM, with a hardcover user's guide. Please direct all orders and general requests for product information to:
P.O. Box 35025
Richmond, VA 23235
(800) 825-7827 (orders only)
(804) 320-7016 (orders and information)
(804) 272-5920 (Fax)