Dark Sky News

The Summer Triangle is an astronomical asterism in the northern hemisphere. Its defining vertices form a large overhead triangle and are Altair, Deneb, and Vega, each the brightest star of its constellation (Aquila, Cygnus, and Lyra, respectively).  Although it may look like a simple flat asterism, it’s really a dramatic three-dimensional arrangement: Vega is about 25 light-years away, Altair about 17, while Deneb is roughly a hundred times farther away—yet Deneb still appears nearly as bright because it is an extraordinarily luminous supergiant.

The triangle conveniently frames one of the richest regions of the northern Milky Way. The dark “Great Rift” runs through it, while Cygnus contains dense star fields, emission nebulae, and strong radio and X-ray sources.

Click on the links to see star maps associated with four nice overhead passes of the Chinese Space Station on Sept. 3 @ 8:46pm , Sept. 5 @ 8:26pm, Sept. 7 @ 8:07pm and Sept. 9 @7:47pm

Click on the links to see star maps associated with two nice overhead passes of the International Space Station on Sept. 9 @ 8:22pm and Sept. 12 @7:34pm

The Sun will shine directly on the equator and there will be nearly equal amounts of day and night throughout the world. Why “September” Equinox? …because this is the first day of fall (autumnal equinox) in the Northern hemisphere but if you are in the Southern hemisphere, it’s the first day of spring (vernal equinox).

Neptune will be at its brightest and most visible of the entire year. It will still be relatively dim and difficult to see, but with the right equipment  this will be the best time to try to see it.

The September Full Moon arrives close to the equinox, giving it its traditional “Harvest Moon” designation.