The intact Summer Triangle is just about to leave the evening sky until summer, but turn the sky upside down to enjoy the great triangle in the morning as if it’s June. Planet Mercury has returned to the western sky south of the Summer Triangle in the evening twilight. Venus has reappeared as Morning Star, to be found south of the triangle, which will be above the east-northeast horizon.

At dusk, scan close above the western horizon to locate Altair, the lowest star of the great triangle and the first to vanish by next week. It will set at 6:04 tonight, 5:41 a week from today. Sunset will be within minutes of 5 o’clock all week. To the right of Altair, see brighter Vega, which sets in the northwest at 7:27. Deneb is a stretch above Vega. Deneb sets at 10:56.

The bright "star" in the west-southwest, left of Altair, is planet Mercury, to go down at 6:36 this evening, along with winter star Fomalhaut to the planet’s left. To recap, at about 5:40, there will be a string of horizon-hugging celestial objects at intervals from Fomalhaut in the southwest to Mercury (west-southwest) to Altair (west) and Vega (northwest). The Summer Triangle commands the sky suspended close to the horizon from west to northwest.

In the morning, perhaps best seen around 6:15, the outstanding triangle is stretched above the skyline from east to northeast. Planet Venus, newly returned as Morning Star, appears to the right of Altair close to the east-southeast horizon. Venus rises at 5:30 tomorrow. Sunrise will be at 7:14 and a minute earlier every day.

Enjoy the sight of the crescent moon close to Saturn, also tomorrow. On Tuesday, a wisp of a crescent will be near Venus. New moon, when the moon is dark, occurs at 4:39 p.m. on the 30th. It’s the second new moon in January!

To contact Judy Isacoff, M.A., go to: www.naturesturn.org