Today:
Autumn has not discouraged the Summer Triangle, just given us a different view. Seen crossing overhead near midnight in the summer, it now appears overhead in the evening. Look for the faintest of the three stars, Deneb, close to the zenith this evening, while Altair shines in the southwest, and the bluish-white Vega gleams sharply, high in the west.
Tuesday:
Directly overhead this evening at 8:40 PM is Deneb, the tail of the Swan, or the top of the Northern Cross. Although Deneb appears as the faintest star of the Summer Triangle, it is by far the most powerful. While Vega shines 40 times brighter than our Sun, and Altair about 10 times brighter, Deneb emits an estimated 200 thousand times more light!
Wednesday:
Arcturus, the brightest star in the evening skies, still close to due west, one quarter of the way up as twilight ends, setting earlier each evening, and heads below the west-northwest horizon at 9:30 PM EDT. Arcturus owes its brilliance to its relatively close position, about 37 light years away, while it sends out 170 times more light than our Sun.