Bob Moler's Ephemeris Blog

This is Ephemeris for Labor Day, Monday, September 2nd. Today the Sun will be up for 13 hours and 9 minutes, setting at 8:16, and it will rise tomorrow at 7:08. The Moon is new today, and won’t be visible.

Let’s look at the skies for September. Daylight hours in the Interlochen/Traverse City area and will drop from 13 hours and 9 minutes today to 11 hours 43 minutes on the 30th. The altitude of the sun above the southern horizon at local noon will be 53 degrees today, and will descend to 42 degrees on the 30th. The official season of summer is getting short too, so enjoy it while you can. Summer will end and autumn will begin at 8:44 a.m. on the 22nd as the Sun will pass overhead at the equator heading southward. It will also mark sunset at the North Pole and sunrise at the South Pole. Southern Hemisphere dwellers will see the start of spring. The summer Milky Way is still visible to explore with binoculars or telescope.

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

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

For a list of constellation names to go with the abbreviations, click here.

• Pointer stars at the front of the bowl of the Big Dipper point to Polaris, the North Star.
• Leaky dipper drips on Leo.
• Follow the arc of the handle of the Big Dipper to the star Arcturus.
• The Summer Triangle is in red.

Twilight Limits, Nautical and Astronomical

			EDT
	Morning	Twilight	Evening	Twilight	Dark	Night	Moon
Date	Astro.	Nautical	Nautical	Astro.	Start	End	Illum.
2024-09-01	5h23m	6h01m	21h28m	22h06m	22h06m	5h21m	0.01
2024-09-02	5h25m	6h02m	21h26m	22h04m	22h04m	5h25m	0.00
2024-09-03	5h26m	6h04m	21h24m	22h01m	22h01m	5h26m	0.01
2024-09-04	5h28m	6h05m	21h22m	21h59m	21h59m	5h28m	0.04
2024-09-05	5h29m	6h07m	21h20m	21h57m	21h57m	5h29m	0.09
2024-09-06	5h31m	6h08m	21h18m	21h55m	21h55m	5h31m	0.15
2024-09-07	5h32m	6h09m	21h16m	21h53m	21h53m	5h32m	0.22
2024-09-08	5h34m	6h11m	21h14m	21h50m	22h09m	5h34m	0.30
2024-09-09	5h35m	6h12m	21h12m	21h48m	22h39m	5h35m	0.40
2024-09-10	5h37m	6h13m	21h10m	21h46m	23h17m	5h37m	0.50
2024-09-11	5h38m	6h15m	21h08m	21h44m	–	5h38m	0.60
2024-09-12	5h40m	6h16m	21h06m	21h42m	0h08m	5h40m	0.70
2024-09-13	5h41m	6h17m	21h04m	21h40m	1h12m	5h41m	0.80
2024-09-14	5h43m	6h18m	21h02m	21h37m	2h26m	5h43m	0.88
2024-09-15	5h44m	6h20m	21h00m	21h35m	3h47m	5h44m	0.95
2024-09-16	5h45m	6h21m	20h58m	21h33m	5h11m	5h45m	0.99
2024-09-17	5h47m	6h22m	20h56m	21h31m	–	–	1.00
2024-09-18	5h48m	6h24m	20h54m	21h29m	–	–	0.98
2024-09-19	5h50m	6h25m	20h52m	21h27m	–	–	0.94
2024-09-20	5h51m	6h26m	20h50m	21h25m	–	–	0.86
2024-09-21	5h52m	6h27m	20h48m	21h23m	21h23m	21h25m	0.77
2024-09-22	5h54m	6h29m	20h46m	21h21m	21h21m	22h03m	0.67
2024-09-23	5h55m	6h30m	20h44m	21h19m	21h19m	22h50m	0.56
2024-09-24	5h56m	6h31m	20h42m	21h17m	21h17m	23h48m	0.46
2024-09-25	5h58m	6h32m	20h40m	21h15m	21h15m	–	0.35
2024-09-26	5h59m	6h34m	20h38m	21h13m	21h13m	0h53m	0.26
2024-09-27	6h00m	6h35m	20h36m	21h11m	21h11m	2h02m	0.18
2024-09-28	6h02m	6h36m	20h34m	21h09m	21h09m	3h12m	0.11
2024-09-29	6h03m	6h37m	20h32m	21h07m	21h07m	4h19m	0.06
2024-09-30	6h04m	6h39m	20h30m	21h05m	21h05m	5h24m	0.02

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

Sep  1  Su            Venus: 24.1° E
     2  Mo   9:55 pm  New Moon
     4  We   9:59 pm  Mercury Elongation: 18.1° W
     5  Th   1:43 am  Moon Descending Node
     5  Th   6:13 am  Moon-Venus: 1.3° N
     5  Th  10:55 am  Moon Apogee: 406200 km
     6  Fr  12:22 pm  Moon-Spica:  .6° S
     7  Sa  11:54 pm  Saturn Opposition
     8  Su  10:52 pm  Mercury-Regulus:  .4° N
    10  Tu   8:29 am  Moon-Antares:  .1° N
    11  We   2:06 am  First Quarter
    12  Th  12:51 am  Moon South Dec.: 28.7° S
    17  Tu   6:14 am  Moon-Saturn:  .3° S
    17  Tu  10:34 pm  Full Moon (Harvest Moon)
    17  Tu  10:45 pm  Partial Lunar Eclipse (See below)
    17  Tu  10:59 pm  Venus-Spica: 2.4° N
    18  We   9:26 am  Moon Perigee: 357300 km
    18  We   3:51 pm  Moon Ascending Node
    20  Fr   6:43 pm  Neptune Opposition
    22  Su   6:16 am  Moon-Pleiades:  .2° S
    22  Su   8:44 am  Autumnal Equinox
    24  Tu   1:04 pm  Moon North Dec.: 28.7° N
    24  Tu   2:50 pm  Last Quarter
    26  Th   6:25 am  Moon-Pollux: 1.8° N
    27  Fr   7:08 am  Moon-Beehive: 3.4° S
    30  Mo   4:59 pm  Mercury Superior Conj.
Oct  1  Tu            Venus: 31.4° E
All event times are given for UTC-4 hr: Eastern Daylight Saving Time.

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.

Sun and Moon Rising and Setting Events

LU                  Ephemeris of Sky Events for Interlochen/TC
September, 2024    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Sun  1| 07:05a  08:18p  13:12 | 09:24p  05:59a |      Rise 06:27a    1%|
|Mon  2| 07:07a  08:16p  13:09 | 09:22p  06:00a |New   Set  08:22p    0%|
|Tue  3| 07:08a  08:14p  13:06 | 09:20p  06:02a |      Set  08:38p    1%|
|Wed  4| 07:09a  08:12p  13:03 | 09:18p  06:03a |      Set  08:53p    3%|
|Thu  5| 07:10a  08:11p  13:00 | 09:16p  06:05a |      Set  09:09p    7%|
|Fri  6| 07:11a  08:09p  12:57 | 09:14p  06:06a |      Set  09:26p   13%|
|Sat  7| 07:12a  08:07p  12:54 | 09:12p  06:07a |      Set  09:45p   20%|
+------+-----------------------+----------------+-----------------------+
|Sun  8| 07:14a  08:05p  12:51 | 09:10p  06:09a |      Set  10:08p   28%|
|Mon  9| 07:15a  08:03p  12:48 | 09:08p  06:10a |      Set  10:38p   38%|
|Tue 10| 07:16a  08:01p  12:45 | 09:06p  06:11a |      Set  11:17p   47%|
|Wed 11| 07:17a  07:59p  12:42 | 09:04p  06:13a |F Qtr Set  12:07a   58%|
|Thu 12| 07:18a  07:58p  12:39 | 09:02p  06:14a |      Set  01:11a   68%|
|Fri 13| 07:19a  07:56p  12:36 | 09:00p  06:15a |      Set  02:25a   78%|
|Sat 14| 07:21a  07:54p  12:33 | 08:58p  06:16a |      Set  03:47a   86%|
+------+-----------------------+----------------+-----------------------+
|Sun 15| 07:22a  07:52p  12:30 | 08:56p  06:18a |      Set  05:10a   93%|
|Mon 16| 07:23a  07:50p  12:26 | 08:54p  06:19a |      Set  06:34a   98%|
|Tue 17| 07:24a  07:48p  12:23 | 08:52p  06:20a |Full  Rise 07:47p  100%|
|Wed 18| 07:25a  07:46p  12:20 | 08:50p  06:22a |      Rise 08:08p   99%|
|Thu 19| 07:27a  07:44p  12:17 | 08:48p  06:23a |      Rise 08:30p   95%|
|Fri 20| 07:28a  07:42p  12:14 | 08:46p  06:24a |      Rise 08:55p   88%|
|Sat 21| 07:29a  07:41p  12:11 | 08:44p  06:25a |      Rise 09:25p   79%|
+------+-----------------------+----------------+-----------------------+
|Sun 22| 07:30a  07:39p  12:08 | 08:42p  06:27a |      Rise 10:02p   69%|
|Mon 23| 07:31a  07:37p  12:05 | 08:40p  06:28a |      Rise 10:50p   58%|
|Tue 24| 07:33a  07:35p  12:02 | 08:38p  06:29a |L Qtr Rise 11:47p   48%|
|Wed 25| 07:34a  07:33p  11:59 | 08:36p  06:30a |      Rise 12:53a   37%|
|Thu 26| 07:35a  07:31p  11:56 | 08:34p  06:32a |      Rise 02:02a   28%|
|Fri 27| 07:36a  07:29p  11:53 | 08:32p  06:33a |      Rise 03:11a   20%|
|Sat 28| 07:37a  07:27p  11:50 | 08:30p  06:34a |      Rise 04:18a   12%|
+------+-----------------------+----------------+-----------------------+
|Sun 29| 07:39a  07:25p  11:46 | 08:28p  06:35a |      Rise 05:24a    7%|
|Mon 30| 07:40a  07:24p  11:43 | 08:27p  06:37a |      Rise 06:27a    3%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

Generated using my LookingUp for DOS app.