Zodiacal Light Above Haleakala
March 19, 2010
Under favorable conditions zodiacal light is a beautiful and mysterious sight. In the Northern Hemisphere it’s best seen in the spring (February and March) about an hour after sunset and in the fall (September and October) about an hour before sunrise. At these times the ecliptic is at a steep angle to the horizon and so the zodiacal light is easier to detect. Scattered sunlight from the dust between the Sun and Earth appear as a huge, soft, radiant pyramid of white light extending from the horizon with its axis centered and peaking in the constellations of the zodiac. Until very recently, it was thought that dust particles from the asteroid belt were responsible for scattering the sunlight. However, it now seems the scattering is largely attributable to dust from comets. As bright as the zodiacal light is most people haven’t seen this phenomenon because it’s best seen from very dark locations with a transparent sky. These conditions aren’t met where most people live; in urban complexes and in any area where light pollution dims the night sky. Moonlight, haze and fog also interfere with observing the zodiacal light.
The photo above is a stacked composite taken from the Haleakala Observatory, on Magnetic Peak on the island of Maui, Hawaii. Note that zodiacal light is fainter than what the photo shows but this view does show what’s perceived. For astronomers at Haleakala Observatory the zodiacal light is like light pollution and wipes out visual work. Photo taken on February 28, 2010.