Airglow and Zodiacal Light
February 06, 2011
The time exposed photo above showing both zodiacal light and airglow were observed on the evening of January 3, 2011 from the Great Plains of eastern, Kansas. Zodiacal light is the faint, conical shaft of light angled from Jupiter toward the center of the horizon. It’s now thought that scattering of sunlight by dust particles from comets that passed by long ago causes this phenomenon.
Airglow is visible here as a reddish glow. It’s believed to be produced by weak emission of oxygen in the thermosphere and is a reason why the night sky isn’t totally dark. The streak at right center, forming a “V” with the zodiacal light, is a gap in the airglow layer. Gravity waves on occasion apparently disturb airglow, forming irregularities seen as bands and streaks. Objects that might pass through the airglow layer likely disrupt it as well. Like all other faint celestial objects and atmospheric phenomena, airglow and zodiacal light are easier to detect far away from city lights. It's best to look for the zodiacal light about 90 minutes after sunset in late February and early March when the Earth is steeply inclined to the ecliptic, making the zodiacal light somewhat more noticeable. The Moon won’t be a factor this year during these times.