Bob Moler's Ephemeris Blog

This is Ephemeris for Tuesday, September 30th. Today the Sun will be up for 11 hours and 44 minutes, setting at 7:24, and it will rise tomorrow at 7:41. The Moon, 1 day past first quarter, will set at 12:44 tomorrow morning.

Let’s look at the skies for this month of October. The Sun will still be moving south rapidly. Daylight hours in the Interlochen/Traverse City area will drop from 11 hours and 41 minutes tomorrow to 10 hours 12 minutes on the 31st. The altitude of the sun above the southern horizon at local noon will be 42 degrees tomorrow, and will descend to 31 degrees on Halloween, also in the Interlochen/Traverse City area. The Straits area will have the sun a degree lower. Local noon, when the Sun is due south, will be about 1:30 pm in Interlochen and Traverse City. Bits of Halley’s comet will return later in the month as the Orionid meteor shower. Dark skies will prevail this year for the Orionids

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

October Evening Star Chart

The planets and stars are plotted for the 15th at 9 PM EDT in the evening and 6 AM on the 16th 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.

October 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.
• DracR – Draconid Radiant – Peaks the 8th – Zenithal Hourly Rate < 10 with rare outbursts of a thousand an hour, though not expected this year. It’s hindered this year by the bright moon.
• OriR – Orionid Radiant – Peak 21st – Zenithal Hourly Rate = 20

Twilight Limits, Nautical and Astronomical

			EDT
	Morning	Twilight	Evening	Twilight	Dark	Night	Moon
Date	Astro.	Nautical	Nautical	Astro.	Start	End	Illum.
2025-10-01	6h05m	6h40m	20h29m	21h03m	0h44m	6h05m	0.72
2025-10-02	6h07m	6h41m	20h27m	21h01m	1h56m	6h07m	0.81
2025-10-03	6h08m	6h42m	20h25m	20h59m	3h11m	6h08m	0.88
2025-10-04	6h09m	6h43m	20h23m	20h57m	4h27m	6h09m	0.95
2025-10-05	6h10m	6h44m	20h22m	20h56m	5h44m	6h10m	0.99
2025-10-06	6h12m	6h46m	20h20m	20h54m	–	–	1.00
2025-10-07	6h13m	6h47m	20h18m	20h52m	–	–	0.98
2025-10-08	6h14m	6h48m	20h16m	20h50m	–	–	0.94
2025-10-09	6h15m	6h49m	20h14m	20h48m	–	–	0.87
2025-10-10	6h17m	6h51m	20h13m	20h46m	20h46m	21h01m	0.78
2025-10-11	6h18m	6h52m	20h11m	20h45m	20h45m	21h57m	0.67
2025-10-12	6h19m	6h53m	20h09m	20h43m	20h43m	23h05m	0.56
2025-10-13	6h20m	6h54m	20h07m	20h41m	20h41m	–	0.45
2025-10-14	6h22m	6h55m	20h06m	20h40m	20h40m	0h19m	0.35
2025-10-15	6h23m	6h57m	20h04m	20h38m	20h38m	1h35m	0.25
2025-10-16	6h24m	6h58m	20h02m	20h36m	20h36m	2h48m	0.17
2025-10-17	6h25m	6h59m	20h01m	20h35m	20h35m	3h57m	0.10
2025-10-18	6h27m	7h00m	19h55m	20h33m	20h33m	5h04m	0.05
2025-10-19	6h28m	7h01m	19h54m	20h31m	20h31m	6h10m	0.02
2025-10-20	6h29m	7h03m	19h52m	20h30m	20h30m	6h29m	0.00
2025-10-21	6h30m	7h04m	19h51m	20h28m	20h28m	6h30m	0.00
2025-10-22	6h31m	7h05m	19h49m	20h27m	20h27m	6h31m	0.03
2025-10-23	6h33m	7h06m	19h48m	20h25m	20h25m	6h33m	0.06
2025-10-24	6h34m	7h08m	19h46m	20h24m	20h24m	6h34m	0.12
2025-10-25	6h35m	7h09m	19h45m	20h22m	20h38m	6h35m	0.19
2025-10-26	6h36m	7h10m	19h43m	20h21m	21h30m	6h36m	0.27
2025-10-27	6h38m	7h11m	19h42m	20h20m	22h31m	6h38m	0.36
2025-10-28	6h39m	7h13m	19h40m	20h18m	23h39m	6h39m	0.45
2025-10-29	6h40m	7h14m	19h39m	20h17m	–	6h40m	0.55
2025-10-30	6h41m	7h15m	19h38m	20h16m	0h50m	6h41m	0.66
2025-10-31	6h42m	7h16m	19h37m	20h14m	2h03m	6h42m	0.76

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
Oct  1  We            Venus: 23.9° W
     5  Su   5:20 AM  Moon Ascending Node
     5  Su  10:46 PM  Moon-Saturn: 3.8° S
     6  Mo  11:48 PM  Full Moon
     8  We   8:36 AM  Moon Perigee: 359800 km
     8  We   5:08 PM  Jupiter-Pollux: 6.7° S
    10  Fr   1:20 AM  Moon-Pleiades: 0.9° S
    11  Sa  11:30 PM  Moon North Dec.: 28.5° N
    13  Mo   2:13 PM  Last Quarter
    13  Mo   6:31 PM  Moon-Jupiter: 4.4° S
    13  Mo   7:30 PM  Moon-Pollux: 2.6° N
    14  Tu   6:53 PM  Moon-Beehive: 2° S
    16  Th  12:56 PM  Moon-Regulus: 1.4° S
    18  Sa  12:34 AM  Moon Descending Node
    19  Su   4:25 PM  Mercury-Mars: 2° N
    19  Su   5:37 PM  Moon-Venus: 4° N
    21  Tu   8:07 AM  Orionid Shower: ZHR = 20
    21  Tu   8:25 AM  New Moon
    23  Th  12:15 PM  Moon-Mercury: 2.5° N
    23  Th   7:31 PM  Moon Apogee: 406400 km
    24  Fr   8:15 PM  Moon-Antares: 0.6° N
    26  Su   7:50 AM  Moon South Dec.: 28.5° S
    29  We  11:21 AM  First Quarter
    29  We   4:59 PM  Mercury Elongation: 23.9° 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),
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 Times

LU               Ephemeris of Sky Events for Interlochen/TC
October, 2025    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Wed  1| 07:41a  07:22p  11:41 | 08:25p  06:38a |      Set  01:55a   70%|
|Thu  2| 07:42a  07:20p  11:38 | 08:23p  06:39a |      Set  03:10a   79%|
|Fri  3| 07:43a  07:19p  11:35 | 08:21p  06:40a |      Set  04:26a   87%|
|Sat  4| 07:44a  07:17p  11:32 | 08:20p  06:41a |      Set  05:44a   94%|
+------+-----------------------+----------------+-----------------------+
|Sun  5| 07:46a  07:15p  11:29 | 08:18p  06:43a |      Set  07:03a   98%|
|Mon  6| 07:47a  07:13p  11:26 | 08:16p  06:44a |Full  Rise 06:53p  100%|
|Tue  7| 07:48a  07:11p  11:23 | 08:14p  06:45a |      Rise 07:15p   99%|
|Wed  8| 07:49a  07:09p  11:20 | 08:12p  06:46a |      Rise 07:42p   95%|
|Thu  9| 07:51a  07:08p  11:17 | 08:11p  06:47a |      Rise 08:16p   88%|
|Fri 10| 07:52a  07:06p  11:14 | 08:09p  06:49a |      Rise 09:00p   80%|
|Sat 11| 07:53a  07:04p  11:10 | 08:07p  06:50a |      Rise 09:57p   69%|
+------+-----------------------+----------------+-----------------------+
|Sun 12| 07:54a  07:02p  11:07 | 08:05p  06:51a |      Rise 11:05p   58%|
|Mon 13| 07:56a  07:01p  11:04 | 08:04p  06:52a |L Qtr Rise 12:19a   47%|
|Tue 14| 07:57a  06:59p  11:01 | 08:02p  06:54a |      Rise 01:34a   37%|
|Wed 15| 07:58a  06:57p  10:58 | 08:00p  06:55a |      Rise 02:47a   27%|
|Thu 16| 07:59a  06:55p  10:55 | 07:59p  06:56a |      Rise 03:57a   18%|
|Fri 17| 08:01a  06:54p  10:52 | 07:57p  06:57a |      Rise 05:04a   11%|
|Sat 18| 08:02a  06:52p  10:49 | 07:55p  06:59a |      Rise 06:09a    6%|
+------+-----------------------+----------------+-----------------------+
|Sun 19| 08:03a  06:50p  10:47 | 07:54p  07:00a |      Rise 07:14a    2%|
|Mon 20| 08:05a  06:49p  10:44 | 07:52p  07:01a |      Rise 08:19a    0%|
|Tue 21| 08:06a  06:47p  10:41 | 07:51p  07:02a |New   Set  06:32p    0%|
|Wed 22| 08:07a  06:45p  10:38 | 07:49p  07:03a |      Set  06:54p    2%|
|Thu 23| 08:09a  06:44p  10:35 | 07:48p  07:05a |      Set  07:21p    6%|
|Fri 24| 08:10a  06:42p  10:32 | 07:46p  07:06a |      Set  07:55p   11%|
|Sat 25| 08:11a  06:41p  10:29 | 07:45p  07:07a |      Set  08:38p   17%|
+------+-----------------------+----------------+-----------------------+
|Sun 26| 08:13a  06:39p  10:26 | 07:43p  07:08a |      Set  09:30p   25%|
|Mon 27| 08:14a  06:38p  10:23 | 07:42p  07:10a |      Set  10:31p   34%|
|Tue 28| 08:15a  06:36p  10:20 | 07:41p  07:11a |      Set  11:38p   43%|
|Wed 29| 08:17a  06:35p  10:18 | 07:39p  07:12a |F Qtr Set  12:50a   53%|
|Thu 30| 08:18a  06:33p  10:15 | 07:38p  07:13a |      Set  02:03a   63%|
|Fri 31| 08:19a  06:32p  10:12 | 07:37p  07:14a |      Set  03:17a   73%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

Generated using my LookingUp for DOS app.