At about an hour after sunset on Saturday, February 7, and for the next two weeks afterward, keen sky-watchers in the Northern Hemisphere can hunt down one of the most elusive of astronomical phenomena: zodiacal light.

This pyramid-shaped beam of light is easily mistaken for the lights of a far-off city just over the dark horizon in the countryside. It has also been called the “false dawn.” But this light is more ethereal; it is caused by sunlight reflecting off cosmic dust between the planets.

The best time to catch this ghostly sky light is about an hour after sunset, looking toward the western horizon from the dark countryside.

This celestial phenomenon is actually the reflection of billions of dust-size particles left behind in interplanetary space after the planets formed about 4.6 billion years ago.