Multiyear Interactive Computer Almanac (MICA)
Astronomical Applications Dept. Astronomical Applications Dept.
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Multiyear Interactive Computer Almanac

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

About MICA

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
Geophysics Meteorology Environmental science
Operations planning Accident reconstruction and litigation Illumination engineering
Architecture Photography  

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:

New features and changes in MICA 2.2/2.2.1/2.2.2 include

MICA Windows sample screens (Windows 7):

MICA Mac sample screens (Mac OS X):

System Requirements

Minimum system requirements for Windows edition:

Minimum system requirements for Mac OS edition:

"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

Software Updates

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.

Full versions of the software and updates are available from Willmann-Bell. Please see the ordering information below.

Frequently Asked Questions and Software Bug Reports

Ordering Information

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:

Mica CDROM image

Willmann-Bell, Inc.
P.O. Box 35025
Richmond, VA 23235

(800) 825-7827 (orders only)
(804) 320-7016 (orders and information)
(804) 272-5920 (Fax)