Bob Moler's Ephemeris Blog

This is Ephemeris for Friday, August 23rd. Today the Sun will be up for 13 hours and 39 minutes, setting at 8:34, and it will rise tomorrow at 6:56. The Moon, 3 days before last quarter, will rise at 10:29 this evening.

This evening when it gets dark enough the bright star Deneb in Cygnus the swan will be very high in the east. Deneb is the dimmest star of the Summer Triangle. Of the other stars of the triangle, Vega is nearly overhead, while Altair is lower in the south-southeast. Deneb’s apparent magnitude, or brightness as seen from Earth, makes it the dimmest of the three bright stars. Its vast distance of possibly 2,600 light years is over 100 times the distance of Vega. If brought as close as Vega, Deneb would be as at least as bright as the quarter moon. It is possibly as bright as 200 thousand Suns; and a huge star, possibly as large in diameter as the orbit of the Earth. For all this it is only 19 or so times the mass of the Sun.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). Times will be different for other locations.

Addendum