Bob Moler's Ephemeris Blog

Ephemeris for Monday, September 20th.*  The sun will rise at 7:27.  It’ll be up for 12 hours and 16 minutes, setting at 7:43.   The moon, 3 days before full, will set at 5:48 tomorrow morning.

Yesterday Mercury was at it greatest angular separation from the sun.  It is now best seen between 6:30 and 7 a.m. low in the east.  Over the next week it will move back a bit toward the sun and will actually get brighter and its illuminated face gets wider, as its phase increases from half  illuminated to gibbous.  It looks very tiny in telescopes.  Farther from the sun the giant planet Jupiter will appear opposite the sun in the sky, rising at sunset.  Jupiter is that bright ‘star’ seen in the east and southeastern sky in the evening.  Today it is at its closest to the earth.  Because Jupiter is 5 times the earth’s distance from the sun, subtracting the earth’s solar distance from Jupiter; it will be 4 times the earth-sun distance or 368 million miles away.  We’ll visit Jupiter later this week.

*Times are for the Grand Traverse Area of Northern Michigan, USA.