Bob Moler's Ephemeris Blog

This is Bob Moler with Ephemeris for Tuesday, September 1st. Today the Sun will be up for 13 hours and 14 minutes, setting at 8:19, and it will rise tomorrow at 7:06. The Moon, 3 days before last quarter, will rise at 10:00 this evening.

Let’s look at the skies for the month of September, a transition month between summer and autumn. The Sun will be moving at its greatest speed in its retreat to the south. Daylight hours in the Interlochen/Traverse City area and will drop from 13 hours and 14 minutes today to 11 hours 45 minutes on the 30th. The altitude of the Sun above the southern horizon at local noon will be 54 degrees today, and will descend to 42 degrees on the 30th. The season of summer is getting short, so enjoy it while you can. Summer ends and autumn begins at 8:06 p.m. with the autumnal equinox on September 22nd. The Harvest Moon will occur on the 26th, being the closest full moon to the autumnal equinox.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

September Evening Star Chart

The planets and stars are plotted for the 15th at 10 p.m. EDT in the evening and 6 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian, West 75° longitude. (An hour 45 minutes behind our daylight saving time meridian during EDT). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes earlier than the current time.

September Morning Star Chart

Twilight Limits, Nautical and Astronomical

Twilight calendar was generated using Cartes du Ciel (Sky Charts).

See my blog post: Twilight Zone for the definitions of the different periods of twilight here: https://bobmoler.wordpress.com/2018/09/27/.

NASA Calendar of Planetary Events

Date         Time     Event
Sep  1  Tu            Venus: 44.6° E
     1  Tu   9:27 AM  Venus-Spica: 1.4° S
     3  Th   8:03 AM  Moon-Pleiades: 1.2° S
     4  Fr   3:51 AM  Last Quarter
     5  Sa   2:12 AM  Moon North Dec.: 28.1° N
     6  Su   2:24 PM  Moon-Mars: 3° S
     6  Su   4:26 PM  Moon Perigee: 368300 km
     8  Tu  12:43 AM  Moon-Beehive: 0.5° S
     8  Tu   2:13 PM  Moon-Jupiter: 0.8° S
     9  We   3:17 PM  Moon Descending Node
    10  Th  11:27 PM  New Moon
    13  Su   4:53 PM  Moon-Spica: 2.6° N
    14  Mo   7:10 AM  Moon-Venus: 0.6° S
    16  We   9:42 PM  Mars-Pollux: 5.9° S
    17  Th   8:18 AM  Moon-Antares: 0.6° N
    18  Fr   2:54 PM  Moon South Dec.: 28.1° S
    18  Fr   4:44 PM  First Quarter
    18  Fr  11:00 PM  Moon Apogee: 404200 km
    22  Tu   8:06 PM  Autumnal Equinox
    23  We  10:40 PM  Moon Ascending Node
    25  Fr   8:13 PM  Neptune Opposition
    25  Fr   9:49 PM  Mercury-Spica: 0.9° N
    26  Sa  12:49 PM  Full Moon (Harvest Moon)
    30  We   1:39 PM  Moon-Pleiades: 1.1° S

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC), with modifications by the author.
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html.

If you go to the above site, you can print out a list like the above for the entire year or calendar pages for your time zone.