Bob Moler's Ephemeris Blog

Ephemeris for Tuesday, June 25th.  Today the sun will be up for 15 hours and 33 minutes, setting at 9:31.   The moon, 2 days past full, will rise at 11:07 this evening.  Tomorrow the sun will rise at 5:58.

This time of year one can see, on rare occasions, some ghostly clouds called noctilucent clouds.  Noctilucent means night shining.  These are silvery clouds that can be seen near the end of twilight.  We’re a bit south of the prime latitudes to see them from 50 to 70 degrees both north and south of the equator.  I’ve seen them but a few times.  They move rather rapidly, even though they’re at an altitude of around 50 miles.  The clouds appear to be made of ice crystals that possibly form around meteoritic dust or volcanic ash.  Their appearance cannot be predicted, but be aware that they may appear near the end of twilight and they are white, move rapidly, and are not the twilit clouds lower down.

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

Addendum

Noctilucent clouds, Kuresoo bog, Soomaa National Park, Estonia. July 26, 2009 by Martin Koitmäe. From Wikimedia Commons.