Zodiacal Light Over Western Texas

April 02, 2011

: Chris G Grohusko 
Summary Author: Chris G Grohusko; Jim Foster

Th ephoto above featuring the zodiacal light was taken after astronomical twilight -- about 90 minutes after sunset or when the geometric center of the Sun is 18 degrees or more below the horizon. Zodiacal light is a cone-shaped, moderately faint glow seen on the same horizon as the setting or rising Sun and aligned with the plane of the ecliptic. It’s now believed to result from dust particles scattering sunlight in the orbits of comets. Zodiacal light is best observed in late winter/early spring after sunset and late summer/early fall before sunrise, when the ecliptic is relatively high in the sky. However, as shown here, in late autumn, it may also be seen within a few weeks of the solstice if the sky is sufficient dark.

Above the Yucca at lower center is the constellation of Virgo. Spica, the brightest star in Virgo, is the white streak immediately above the plant. The constellation of Corvus is at far right. Note that the long exposure was used for illustrative purposes – zodiacal light won’t look this vivid with the naked eye. Photo taken at 4:30 a.m. on November 30, 2001 approximately 70 mi (113 km) east of El Paso, Texas, near the town of Cornudas, Texas.

Photo details: Pentax k1000 camera; on tripod with cable release; 3 minute exposure; 28mm lens at f/2.8; on Kodak Ektachrome slide film 400.