It may be hard to see at this resolution, but in the center of the shadow is the small, black umbra, the area of the Moon's shadow in which the sun's disk is completely hidden. Viewers on the ground in the path of the umbra see a total solar eclipse, while those in the penumbra see a partial eclipse.

The animation was rendered in LightWave 3D, a general-purpose animation program more typically used to create movie and television special effects. In reality, the penumbra darkens toward the middle more than is shown here, so that the umbra can't be distinguished. The times displayed are UT.

Click on the image to see a web-sized QuickTime version of the animation (about 206 KB).

To find out more about this eclipse, visit the NASA Goddard Space Flight Center Eclipse Home Page, where you'll find links to maps, tables and all kinds of nifty technical information.

I didn't include any background stars in this animation, but I have in others. My star objects are built from digital catalogs obtained from Goddard's Astronomical Data Center.

Some time ago I ported Elwood Downey's old Ephem program to the Amiga and added an ARexx port, which allows me to write scripts that use Ephem to do custom astronomical calculations. The eclipse script extracts the positions of the sun and Moon at regular intervals during the eclipse, converting from heliocentric coordinates to LightWave's left-handed Cartesian system. Since an accurate scale model of the solar system would exceed the numerical precision of LightWave's raytracer, the conversion substantially reduces the distances involved.

Ephem was long ago superceded by XEphem for Unix. The original Ephem's algorithms were based on Peter Duffet-Smith's Astronomy with your Personal Computer. For the Amiga version, I ported Duffett-Smith's eclipse search and display routines, which hadn't yet been included in Ephem.

The Earth image used in this animation was created by Rick Kohrs (rickk@ssec.wisc.edu), Space Science and Engineering Center, University of Wisconsin-Madison, from IR data taken by the GMS, GOES 7, METEOSAT 3 and 4 and NOAA 11 and 12 satellites on 26 August 1993. Since my animation was rendered before the eclipse, I couldn't use real weather data, but this is hopefully representative of August weather patterns.

In fact, real cloud images already have the shadow in them, which would've been cheating! You might also enjoy this Astronomy Picture of the Day, a photograph of the Moon's shadow during this eclipse taken from the Mir space station.