Vanishing Lion

With another spring only a memory now, one of the season’s leading star patterns is plunging from view in the evening sky.

Leo, the lion, is in the west as darkness falls. It’s dropping head first, like a real lion pouncing on its prey. Its brightest star, Regulus, is quite low in the sky, so any trees or buildings along the horizon will block it from view.

The lion’s head and mane spread out to the upper right of Regulus. His body is above Regulus, with his tail, the star Denebola, far to the upper left of Regulus.

Leo is associated with spring because it springs highest across the sky then, and is in view for most of the night. But every night, the stars rise and set about four minutes earlier than the night before. So as the weeks roll by, so do the stars. Those that are prominent during spring disappear during the longer nights of summer.

And on the opposite side of the sky, stars that were hidden during spring evenings rise to prominence. So while Leo and other spring constellations vanish, Scorpius and Sagittarius line up for their own prime-time appearances.

Leo isn’t quite done, though. The Sun is setting a little earlier each night, which gives Leo a bit of extra time before it vanishes from the evening sky. Look for it low in the west as the color of twilight drains away. Regulus will disappear by month’s end, with the rest of the lion following as we head into August.

Tomorrow: the eye of the bull in the morning sky.

Script by Damond Benningfield