Detailed Maps of the Umbral Path

The path of totality has been plotted on a set of ten detailed maps appearing in the last section of this publication. The maps are constructed from the Digital Chart of the World (DCW), a digital database of the world developed by the U.S. Defense Mapping Agency (DMA). The primary sources of information for the geographic database are the Operational Navigation Charts (ONC) and the Jet Navigation Charts (JNC) developed by the DMA. The original map scale of these maps was 1:1,000,000. Previous users of these publications will be familiar with ONC and JNC charts as hard-copy versions were used to show the eclipse paths in past bulletins.

The scale of these maps has been increased to 1:2,500,000, adequate for showing major transportation routes, cities and villages, coarse topography, lakes and rivers, suitable for eclipse expedition planning. Caution should be employed in using these maps as no distinction has been made between major highways and second class soft-surface roads in the map plot. Those eclipse viewers who require more detailed plots of the eclipse track should use the data contained within the tables in this publication and larger scale background maps.

The DCW database was assembled in the 1980s and contains names of places that are no longer used in some parts of Africa, particularly Zimbabwe. Where possible, modern names have been substituted for those in the database but this correction could not be applied to all sites. Some areas of missing topographic data appear as blank white rectangles on the map background.

Northern and southern limits as well as the center line of the path are plotted using data from Table 7. Although no corrections have been made for center of figure or lunar limb profile, they have little or no effect at this scale. Atmospheric refraction has not been included, as its effects play a significant role only at very low solar altitudes. In any case, refraction corrections to the path are uncertain since they depend on the atmospheric temperature-pressure profile, which cannot be predicted in advance. If observations from the graze zones are planned, then the zones of grazing eclipse must be plotted on higher scale maps using coordinates in Table 8. See PLOTTING THE PATH ON MAPS for sources and more information. The paths also show the curves of maximum eclipse at two-minute increments in UT. These maps are also available on the Web.

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