Archive for July 18, 2014

07/18/2014 – Ephemeris – Deneb is the brightest star of the Summer Triangle… Really

July 18, 2014 Comments off

Ephemeris for Friday, July 18th.  Today the sun will be up for 15 hours and 8 minutes, setting at 9:22.   The moon, at last quarter today, will rise at 12:58 tomorrow morning.  Tomorrow the sun will rise at 6:15.

At 11 this evening the bright star Deneb in Cygnus the swan will be moderately high in the east northeast.  Deneb is the dimmest star of the summer triangle.  Of the other stars of the triangle, Vega is nearly overhead, and Altair to the southeast.  While Deneb’s apparent magnitude, or brightness as seen from Earth, makes it the dimmest of the three bright stars, Deneb has a vast distance of possibly 1,550  light years.  If brought as close as Vega, Deneb would be several times brighter than Venus.  For all this it is only 13-20 times the mass of the sun.  It will have an extremely short life and will explode, go supernova, in perhaps a few million years.  Closer to home, check out the Sun at Kingsley Heritage Days This Saturday and Sunday.

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


Northern Cross

Deneb and the Northern Cross section of Cygnus the swan. Created using Stellarium.

Deneb & North American Nebula

One of my old photographs of Deneb and the North American Nebula digitized from a slide.

The North American Nebula, visible as a faint smudge in binoculars or the naked eye may be ionized and illuminated by Deneb.  It’s distance appears to be comparable to that of Deneb.

You may note that previous postings about Deneb over the years have given different distances of Deneb.  That just denotes how difficult it is to pin down its distance.