A Raster-oriented Method for Creating Eclipse Maps

Abstract

Traditional total solar eclipse maps based on 19th-century calculation methods do not take full advantage of important refinements recently made possible by fast computers and high-resolution digital elevation models of both the Earth and the Moon. Ignoring the terrain of both bodies introduces errors on the order of kilometers in the ground track of the umbra and seconds in the duration and contact times of totality. While this has been understood to some degree for decades, it has not been visualized in maps until quite recently, revealing only in the last decade the surprising polygonal shape of the umbra. Beginning in December of 2016, we published maps and animations of the 2017 August 21 total solar eclipse created with a raster-oriented approach that relies on remote-sensing data sets and computer graphics techniques to produce more accurate maps and professional-quality animations. These were an important component of NASA’s public outreach for the 2017 eclipse.

Keywords

• Solar eclipses
• Computational astronomy
• History of astronomy