~ St. Maarten’s Backyard Astronomy for July 20 & 21 ~
Sun rises at 5:46am
Sun sets at 6:50pm
Moon phase: 3rd quarter, waning gibbous
Moon sets: 8:46am, Saturday
Moon rises: 9:39pm, Saturday
This weekend has us looking eastward for the demur arrangement of stars known as the Summer Triangle. It’s not really a constellation, but a noticeable group of three stars from different constellations. One method for finding the Triangle is to look east soon after sunset. These three stars are, after all, among the brightest in the sky.
The star Deneb is the northernmost star in the Summer Triangle. Its constellation is Cygnus the Swan. In a dark sky, you can sometimes see Cygnus as if she is flying along the starlit trail of the Milky Way. If it’s very dark out, you might notice that there is a cross within the Triangle. The constellation Cygnus is that cross. In fact, the constellation Cygnus is sometimes called the Northern Cross. The Cross is – more or less – just another way to see the Swan.
Other Summer Triangle stars and their constellations are: Vega within its constellation Lyra the Harp, and Altair within its constellation Aquila the Eagle. Look near the horizon for Altair, near the bottom of the Summer Triangle; that is, it’s the last of these three bright stars to ascend over the horizon.
In Asian cultures, Altair and Vega offer a wonderful imagery. It is one of the most beautiful love stories associated with the stars of the night sky. There are many variations, such as in China, the legend speaks of a forbidden romance between the goddess Zhinu – represented by Vega – and a humble farm boy, Niulang – represented by the star Altair. Separated in the night sky by the Milky Way, or Celestial River, the two lovers are allowed to meet only once a year. It’s said that meeting comes on the 7th night of the 7th moon, when a bridge of magpies forms across the Celestial River, allowing the two lovers to be reunited. Their reunion marks the time of the Qixi Festival.
In the Japanese version, Vega is called Tanabata, a celestial princess. She falls in love with a mortal, Kengyu, represented by the star Altair. In each variation, the lovers are separated by the Celestial River and are only allowed to bridge the gap once a year.
The whole Summer Triangle area is great to observe, either with binoculars or with just your eyes. Enjoy the twilight hours, as the sky darkens, look for these stars and others, with a clear appreciation of our natural blessings.
Thank you for keeping up with the Night Sky articles. If you are out later on in the week, each star rises about four minutes earlier each day than written here, and the moon rises 50 minutes later. Night Sky is researched and compiled by Lisa Davis-Burnett. Earthsky.org is a key resource for information and images. Questions or comments? Email [email protected]