The zodiacal light is an astronomical phenomenon I don’t mention very often, because it is best seen away from city lights and the moon. Actually, it is not all that faint, and it is quite large. The zodiacal light is best seen during twilight in the west after sunset in spring and in the east before sunrise in the autumn.

The zodiacal light will be visible in the predawn sky the next few days until the moon gets in the way. Starting Friday, look toward the east from about 4:30 to 5:30 a.m. The zodiacal light is a quite large pyramidal glow in the eastern sky before sunrise. It is surprisingly bright and quite large, extending at least half-way up the sky from the horizon. I can actually see it sometimes in the early morning sky at my house in the foothills, though it is much more impressive out of town.

The first time you see the zodiacal light you might mistake it for the glow of city lights. It is actually the glow of microscopic dust particles originating from comets and asteroids. These innumerable fine grains lie along the orbital plane of the solar system. The Sun’s light reflects off them producing a distinct glow best seen during those times when the plane of the solar system (the ecliptic plane) is near perpendicular to the eastern or western horizon.