Archive for July 2, 2018

07/02/2018 – Ephemeris – The starry triangle of summer

July 2, 2018 Comments off

Ephemeris for Monday, July 2nd. Today the Sun will be up for 15 hours and 30 minutes, setting at 9:31, and it will rise tomorrow at 6:02. The Moon, half way from full to last quarter, will rise at 12:19 tomorrow morning.

Now that it’s summer it’s time to look for the Summer Triangle in the sky. It’s seen rising in the east as it gets dark. Highest of the three bright stars is Vega in the constellation Lyra the harp, whose body is seen in a narrow parallelogram nearby. The second star of the triangle is Deneb lower and left of Vega, It appears dimmer than Vega because it is by far the most distant of the three. The third star of the Summer Triangle is seen farther below and a right of Vega. It is Altair in Aquila the eagle, and the closest. Altair is 16.5 light years away, Vega is 27 light years while Deneb actually one of the brighter stars known, is 1500 or more light years away. It’s distance is not well known.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


The Summer Triangle July 5, 2012 at 11 p.m. Created using Stellaruim and The Gimp.

The Summer Triangle. Created using Stellarium.