Algorithms, Ephemerides and Parameters

Algorithms for the eclipse predictions were developed by Espenak primarily from the Explanatory Supplement [1974] with additional algorithms from Meeus, Grosjean and Vanderleen [1966] and Meeus [1982]. The solar and lunar ephemerides were generated from the JPL DE200 and LE200, respectively. All eclipse calculations were made using a value for the Moon's radius of k=0.2722810 for umbral contacts, and k=0.2725076 (adopted IAU value) for penumbral contacts. Center of mass coordinates were used except where noted. Extrapolating from 1996 to 1998, a value for T of 64.6 seconds was used to convert the predictions from Terrestrial Dynamical Time to Universal Time. The international convention of presenting date and time in descending order has been used throughout the bulletin (i.e., year, month, day, hour, minute, second).

The primary source for geographic coordinates used in the local circumstances tables is The New International Atlas (Rand McNally, 1991). Elevations for major cities were taken from Climates of the World (U. S. Dept. of Commerce, 1972).

All eclipse predictions presented in this publication were generated on a Macintosh PowerPC 8500 computer. Word processing and page layout for the publication were done using Microsoft Word v5.1. Figures were annotated with Claris MacDraw Pro 1.5. Meteorological diagrams were prepared using Corel Draw 5.0 and converted to Macintosh compatible files. Finally, the bulletin was printed on a 600 dpi laser printer (Apple LaserWriter Pro).

The names and spellings of countries, cities and other geopolitical regions are not authoritative, nor do they imply any official recognition in status. Corrections to names, geographic coordinates and elevations are actively solicited in order to update the data base for future eclipses. All calculations, diagrams and opinions presented in this publication are those of the authors and they assume full responsibility for their accuracy.

Conversion of the text to HTML format was accomplished using Adobe Pagemaker 6.5 Microsoft Word 6.0.1 for Macintosh. Some of the diplayed equations were converted to GIF images using the Microsoft Equation Editor for Macintosh and Adobe Photoshop 3.0.5. The original, encapsulated PostScript version of the figures were converted to PICT files, and the PICT versions converted to CompuServe GIF format using Adobe Photoshop 3.0.5 and GIFconverter 2.3.7. The ONC maps were converted from TIFF to JPEG format using Adobe Photoshop 4.0 Conversion of the manuscript and figures, aside from some editing directly on the server, was carried out on a Power Computing PowerTower Pro 225 and an Apple Power Macintosh 8100/80.

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