
ANNEXE:

The software "eclipsa" computes the times of contacts (exterior and interior) of a Solar eclipse, given the ephemeridae of Sun and Moon, apparent topocentric (local horizon coordinates). The ephemeridae should be given in MICA format (Multiyear Interactiv Computer Almanac) - a software by USNO (v. 1.0b3) and should be computed in local coordinates for a given place, using the same time step (recommended 1s) and limits (for start and stop). 

An example has been provided for Bucharest at total Solar eclipse on 11 August 1999. In Romanian, Soare = Sun; Luna = Moon. The following files are given:

soare.zip - to be unzipped using WinZip - will get soare.dat
luna.zip  - to be unzipped using WinZip - will get luna.dat

The software uses the Moon radius. The default value used in the program is 1737.3 Km, a mean between the recommended values of 1738.09 (for both exterior contacts), and 1736.65 (for both interior contacts). 

Running the program using the Bucharest's coordinates listed with the referred publication will get the following results:

All times in UT    Espenak & Anderson             Ovidiu
----------------------------------------------------------------
First Contact           9:41:24.9                   24.0
Second Contact         11:05:47.7                   47.0
Third Contact          11:08:10.0                    9.0
Fourth Contact         12:28:43.6                   43.0
Eclipse's Maximum      11:06:58.9                   57.0

Of course, to have a precision of 0.1s we should get the ephemeridae using a step of 0.1s. Nevertheless, this would be superflue, because of the variable radius of the Moon. In fact, for an accurate result we should take into account the Moon's topography, that introduces differences of level of about 1Km. 

References: 
- Total Solar Eclipse of 1999 August 11 - Fred Espenak and Jay Anderson, NASA Reference Publication 1398, March 1997;
- Turbo C++ v.1.0 (DOS) software, Borland International, 1990.

Author: Ovidiu Vaduvescu
Email: ovidiuv@yahoo.com
Internet: http://www.ipgnet.com/~ovidiu

