Bob Moler's Ephemeris Blog

This is Bob Moler with Ephemeris for Friday, August 1st. Today the Sun will be up for 14 hours and 38 minutes, setting at 9:08, and it will rise tomorrow at 6:30. The Moon, at first quarter today, will set at 12:21 tomorrow morning.

Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 38 minutes today to 13 hours 16 minutes on the 31st. The altitude of the Sun at local noon, that is, degrees of angle above the horizon, will decrease from 63 degrees today to just over 53 degrees on the 31st. Straits area listeners can subtract one more degree from those angles, but their daylight hours will be a few minutes longer. Local noon, when the Sun is due south, is about 1:43 p.m. The Perseid meteor shower will reach its peak on the afternoon of the12th. But, the waning gibbous Moon will interfere with all but the brightest meteors. So the best time to see them is after moonset in the morning for the next several days.

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

August Evening Star Chart

The planets and stars are plotted for the 15th at 10 pm EDT in the evening and 4:30 am on the 16th. 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.

Note the chart times are for the mid-month. For each week before then, add ½ hour (28 minutes if you’re picky). For each week after then, subtract ½ hour. The planet positions are updated each Wednesday on this blog. See them for planet positions on dates other than the mid-month.

August 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, and
• Extend like a spike to Spica.
• The Summer Triangle is in red.
• PerR is the radiant of the Perseid meteor shower (Peaks on the afternoon of the 12th)

Twilight Limits, Nautical and Astronomical

			EDT
	Morning	Twilight	Evening	Twilight	Dark	Night	Moon
Date	Astro.	Nautical	Nautical	Astro.	Start	End	Illum.
2025-08-01	4h27m	5h16m	22h26m	23h15m	–	4h27m	0.57
2025-08-02	4h29m	5h17m	22h25m	23h13m	0h22m	4h29m	0.66
2025-08-03	4h31m	5h19m	22h23m	23h10m	0h50m	4h31m	0.75
2025-08-04	4h33m	5h20m	22h21m	23h08m	1h25m	4h33m	0.83
2025-08-05	4h35m	5h22m	22h20m	23h06m	2h10m	4h35m	0.90
2025-08-06	4h37m	5h23m	22h18m	23h04m	3h07m	4h37m	0.95
2025-08-07	4h39m	5h24m	22h16m	23h02m	4h14m	4h39m	0.99
2025-08-08	4h41m	5h26m	22h15m	23h00m	–	–	1.00
2025-08-09	4h43m	5h27m	22h13m	22h58m	–	–	0.99
2025-08-10	4h44m	5h29m	22h11m	22h55m	–	–	0.96
2025-08-11	4h46m	5h30m	22h09m	22h53m	–	–	0.90
2025-08-12	4h48m	5h32m	22h07m	22h51m	–	–	0.82
2025-08-13	4h50m	5h33m	22h05m	22h49m	–	–	0.72
2025-08-14	4h52m	5h35m	22h04m	22h47m	22h47m	23h11m	0.62
2025-08-15	4h54m	5h36m	22h02m	22h44m	22h44m	23h41m	0.50
2025-08-16	4h55m	5h38m	22h00m	22h42m	22h42m	–	0.39
2025-08-17	4h57m	5h39m	21h58m	22h40m	22h40m	0h20m	0.28
2025-08-18	4h59m	5h41m	21h56m	22h38m	22h38m	1h10m	0.18
2025-08-19	5h01m	5h42m	21h54m	22h36m	22h36m	2h13m	0.11
2025-08-20	5h03m	5h44m	21h52m	22h33m	22h33m	3h25m	0.05
2025-08-21	5h04m	5h45m	21h50m	22h31m	22h31m	4h42m	0.01
2025-08-22	5h06m	5h47m	21h48m	22h29m	22h29m	5h06m	0.00
2025-08-23	5h08m	5h48m	21h46m	22h27m	22h27m	5h08m	0.01
2025-08-24	5h09m	5h50m	21h44m	22h24m	22h24m	5h09m	0.04
2025-08-25	5h11m	5h51m	21h42m	22h22m	22h22m	5h11m	0.09
2025-08-26	5h13m	5h52m	21h40m	22h20m	22h20m	5h13m	0.15
2025-08-27	5h15m	5h54m	21h38m	22h18m	22h18m	5h15m	0.23
2025-08-28	5h16m	5h55m	21h36m	22h15m	22h24m	5h16m	0.31
2025-08-29	5h18m	5h57m	21h34m	22h13m	22h49m	5h18m	0.40
2025-08-30	5h19m	5h58m	21h32m	22h11m	23h21m	5h19m	0.50
2025-08-31	5h21m	5h59m	21h30m	22h09m	–	5h21m	0.59

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

Aug  1  Fr            Venus: 38° W
     1  Fr   8:41 AM  First Quarter
     1  Fr   4:37 PM  Moon Apogee: 404200 km
     3  Su   9:40 PM  Moon-Antares: 0.6° N
     5  Tu   9:37 AM  Moon South Dec.: 28.5° S
     9  Sa   3:55 AM  Full Moon
    11  Mo  10:53 AM  Moon Ascending Node
    12  Tu   2:53 AM  Venus-Jupiter: 0.9° N
    12  Tu  11:05 AM  Moon-Saturn: 4.1° S
    12  Tu   3:47 PM  Perseid Shower: ZHR = 90
    14  Th   2:01 PM  Moon Perigee: 369300 km
    16  Sa   1:12 AM  Last Quarter
    16  Sa  12:09 PM  Moon-Pleiades: 0.9° S
    18  Mo  11:59 AM  Moon North Dec.: 28.6° N
    19  Tu  12:58 AM  Mercury-Beehive: 2.6° S
    19  Tu   5:59 AM  Mercury Elongation: 18.6° W
    19  Tu   5:05 PM  Moon-Jupiter: 4.9° S
    20  We   6:51 AM  Moon-Venus: 5° S
    20  We   8:07 AM  Moon-Pollux: 2.5° N
    21  Th   7:09 AM  Moon-Beehive: 2.1° S
    23  Sa   2:06 AM  New Moon
    24  Su  11:41 AM  Moon Descending Node
    26  Tu  12:41 PM  Moon-Mars: 3° N
    27  We   9:57 AM  Moon-Spica: 1.2° N
    29  Fr  11:34 AM  Moon Apogee: 404600 km
    31  Su   2:25 AM  First Quarter
    31  Su   5:55 AM  Moon-Antares: 0.7° N
    31  Su   1:59 PM  Venus-Beehive: 1.5° S
Sep  1  Mo            Venus: 31.2° W

Planetary 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 Events

LU                  Ephemeris of Sky Events for Interlochen/TC
August, 2025    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Fri  1| 06:29a  09:08p  14:38 | 10:23p  05:13a |F Qtr Set  12:21a   54%|
|Sat  2| 06:30a  09:06p  14:36 | 10:21p  05:15a |      Set  12:49a   64%|
+------+-----------------------+----------------+-----------------------+
|Sun  3| 06:31a  09:05p  14:33 | 10:20p  05:16a |      Set  01:24a   73%|
|Mon  4| 06:32a  09:04p  14:31 | 10:18p  05:18a |      Set  02:10a   81%|
|Tue  5| 06:33a  09:02p  14:28 | 10:16p  05:19a |      Set  03:06a   88%|
|Wed  6| 06:35a  09:01p  14:26 | 10:14p  05:21a |      Set  04:13a   94%|
|Thu  7| 06:36a  09:00p  14:23 | 10:13p  05:22a |      Set  05:26a   98%|
|Fri  8| 06:37a  08:58p  14:21 | 10:11p  05:24a |      Set  06:42a  100%|
|Sat  9| 06:38a  08:57p  14:18 | 10:09p  05:25a |Full  Rise 09:26p   99%|
+------+-----------------------+----------------+-----------------------+
|Sun 10| 06:39a  08:55p  14:15 | 10:07p  05:27a |      Rise 09:47p   97%|
|Mon 11| 06:40a  08:54p  14:13 | 10:05p  05:28a |      Rise 10:06p   91%|
|Tue 12| 06:42a  08:52p  14:10 | 10:04p  05:30a |      Rise 10:26p   84%|
|Wed 13| 06:43a  08:51p  14:07 | 10:02p  05:31a |      Rise 10:47p   75%|
|Thu 14| 06:44a  08:49p  14:05 | 10:00p  05:33a |      Rise 11:11p   64%|
|Fri 15| 06:45a  08:48p  14:02 | 09:58p  05:34a |      Rise 11:41p   53%|
|Sat 16| 06:46a  08:46p  13:59 | 09:56p  05:36a |L Qtr Rise 12:19a   41%|
+------+-----------------------+----------------+-----------------------+
|Sun 17| 06:47a  08:44p  13:56 | 09:54p  05:37a |      Rise 01:10a   30%|
|Mon 18| 06:49a  08:43p  13:54 | 09:52p  05:39a |      Rise 02:12a   20%|
|Tue 19| 06:50a  08:41p  13:51 | 09:50p  05:40a |      Rise 03:25a   12%|
|Wed 20| 06:51a  08:39p  13:48 | 09:48p  05:42a |      Rise 04:41a    6%|
|Thu 21| 06:52a  08:38p  13:45 | 09:46p  05:43a |      Rise 05:57a    2%|
|Fri 22| 06:53a  08:36p  13:42 | 09:44p  05:45a |      Rise 07:10a    0%|
|Sat 23| 06:55a  08:34p  13:39 | 09:42p  05:46a |New   Set  08:54p    1%|
+------+-----------------------+----------------+-----------------------+
|Sun 24| 06:56a  08:33p  13:36 | 09:41p  05:47a |      Set  09:11p    3%|
|Mon 25| 06:57a  08:31p  13:33 | 09:39p  05:49a |      Set  09:27p    8%|
|Tue 26| 06:58a  08:29p  13:31 | 09:37p  05:50a |      Set  09:44p   14%|
|Wed 27| 06:59a  08:27p  13:28 | 09:35p  05:52a |      Set  10:02p   21%|
|Thu 28| 07:00a  08:26p  13:25 | 09:33p  05:53a |      Set  10:23p   29%|
|Fri 29| 07:02a  08:24p  13:22 | 09:31p  05:55a |      Set  10:48p   38%|
|Sat 30| 07:03a  08:22p  13:19 | 09:29p  05:56a |      Set  11:20p   47%|
+------+-----------------------+----------------+-----------------------+
|Sun 31| 07:04a  08:20p  13:16 | 09:27p  05:57a |F Qtr Set  12:01a   57%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

Generated using my LookingUp for DOS app.