Two additional columns are included if the location lies within
the path of the Moon's umbral shadow. The umbral depth is a
relative measure of a location's position with respect to the center
line and path limits. It is a unitless parameter which is defined as:
|u|| = ||umbral depth
||x|| = ||perpendicular distance from the shadow
||R|| = ||radius of the umbral shadow as it
intersects Earth's surface (kilometers)
The umbral depth for a location varies from 0.0 to 1.0. A position at
the path limits corresponds to a value of 0.0 while a position on the
center line has a value of 1.0. The parameter can be used to quickly
determine the corresponding center line duration. Thus, it is a useful
tool for evaluating the trade-off in duration of a location's position
relative to the center line. Using the location's duration and umbral
depth, the center line duration is calculated as:
|D||=||duration of totality on the center line (seconds)|
|d||=||duration of totality at location (seconds)|
The final column gives the duration of totality. The effects of refraction have not been included in these calculations, nor have there been any corrections for center of figure or the lunar limb profile.
Locations were chosen based on general geographic distribution, population, and proximity to the path. The primary source for geographic coordinates 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). In this rapidly changing political world, it is often difficult to ascertain the correct name or spelling for a given location. Therefore, the information presented here is for location purposes only and is not meant to be authoritative. Furthermore, it does not imply recognition of status of any location by the United States Government. Corrections to names, spellings, coordinates and elevations is solicited in order to update the geographic data base for future eclipse predictions.
For countries in the path of totality, expanded versions of the local circumstances tables listing many more locations are available via a special web site of supplemental material for the total solar eclipse of 2001 June 21.
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