Bob Moler's Ephemeris Blog

This is Ephemeris for Thursday, August 1st. Today the Sun will be up for 14 hours and 38 minutes, setting at 9:07, and it will rise tomorrow at 6:30. The Moon, 3 days before new, will rise at 4:03 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 15 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. Local noon, when the Sun is due south, is about 1:43 p.m. The big event of the month will be in the morning sky: The Perseid meteor shower will be best seen on the morning of the 12th after the Moon sets, though members of the shower can be seen now. August is the first of my two favorite months for viewing the wonders of the summer Milky Way.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.

Addendum

August Evening Star Chart

The planets and stars are plotted for the 15th at 10 pm EDT in the evening and 5 am. 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 15th. For each week before the 15th, add ½ hour (28 minutes if you’re picky). For each week after the 15th, subtract ½ hour. The planet positions are updated each Wednesday on this blog. See them for planet positions on dates other than the 15th.

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 morning of the 12th)

Twilight Limits, Nautical and Astronomical

			EDT
	Morning	Twilight	Evening	Twilight	Dark	Night	Moon
Date	Astro.	Nautical	Nautical	Astro.	Start	End	Illum.
2024-08-01	4h28m	5h16m	22h26m	23h14m	23h14m	3h01m	0.05
2024-08-02	4h30m	5h17m	22h24m	23h12m	23h12m	4h04m	0.02
2024-08-03	4h32m	5h19m	22h23m	23h10m	23h10m	4h32m	0.00
2024-08-04	4h34m	5h20m	22h21m	23h08m	23h08m	4h34m	0.01
2024-08-05	4h35m	5h22m	22h19m	23h06m	23h06m	4h35m	0.03
2024-08-06	4h37m	5h23m	22h18m	23h04m	23h04m	4h37m	0.07
2024-08-07	4h39m	5h25m	22h16m	23h01m	23h01m	4h39m	0.13
2024-08-08	4h41m	5h26m	22h14m	22h59m	22h59m	4h41m	0.20
2024-08-09	4h43m	5h28m	22h12m	22h57m	23h03m	4h43m	0.28
2024-08-10	4h45m	5h29m	22h10m	22h55m	23h21m	4h45m	0.36
2024-08-11	4h47m	5h31m	22h09m	22h53m	23h42m	4h47m	0.46
2024-08-12	4h49m	5h32m	22h07m	22h51m	–	4h49m	0.56
2024-08-13	4h50m	5h34m	22h05m	22h48m	0h08m	4h50m	0.66
2024-08-14	4h52m	5h35m	22h03m	22h46m	0h41m	4h52m	0.75
2024-08-15	4h54m	5h37m	22h01m	22h44m	1h26m	4h54m	0.84
2024-08-16	4h56m	5h38m	21h59m	22h42m	2h24m	4h56m	0.91
2024-08-17	4h58m	5h40m	21h57m	22h39m	3h35m	4h58m	0.96
2024-08-18	4h59m	5h41m	21h55m	22h37m	4h55m	4h59m	1.00
2024-08-19	5h01m	5h43m	21h54m	22h35m	–	–	1.00
2024-08-20	5h03m	5h44m	21h52m	22h33m	–	–	0.97
2024-08-21	5h05m	5h46m	21h50m	22h31m	–	–	0.92
2024-08-22	5h06m	5h47m	21h48m	22h28m	–	–	0.84
2024-08-23	5h08m	5h48m	21h46m	22h26m	22h26m	22h29m	0.74
2024-08-24	5h10m	5h50m	21h44m	22h24m	22h24m	22h55m	0.63
2024-08-25	5h12m	5h51m	21h42m	22h22m	22h22m	23h26m	0.52
2024-08-26	5h13m	5h53m	21h40m	22h19m	22h19m	–	0.41
2024-08-27	5h15m	5h54m	21h38m	22h17m	22h17m	0h06m	0.31
2024-08-28	5h17m	5h56m	21h36m	22h15m	22h15m	0h56m	0.22
2024-08-29	5h18m	5h57m	21h34m	22h13m	22h13m	1h56m	0.14
2024-08-30	5h20m	5h58m	21h32m	22h10m	22h10m	3h02m	0.08
2024-08-31	5h21m	6h00m	21h30m	22h08m	22h08m	4h12m	0.03

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
Aug  1  Th            Venus: 15.9° E
     1  Th   1:59 am  Moon North Dec.: 28.5° N
     3  Sa   9:22 pm  Mars-Aldebaran: 4.9° N
     4  Su   7:13 am  New Moon
     4  Su   6:56 pm  Venus-Regulus: 1° N
     5  Mo   6:04 pm  Moon-Venus: 1.9° S
     7  We   1:23 pm  Mercury-Venus: 5.7° N
     8  Th   9:06 pm  Moon Descending Node
     8  Th   9:32 pm  Moon Apogee: 405300 km
    10  Sa   5:34 am  Moon-Spica:  .8° S
    12  Mo   9:38 am  Perseid Shower: ZHR = 90
    12  Mo  11:19 am  First Quarter
    14  We  12:38 am  Moon-Antares:  °
    14  We  10:45 am  Mars-Jupiter:  .3° N
    15  Th   4:10 pm  Moon South Dec.: 28.5° S
    18  Su   9:48 pm  Mercury Inferior Conj.
    19  Mo   2:26 pm  Full Moon
    20  Tu  10:54 pm  Moon-Saturn:  .4° S
    21  We   1:05 am  Moon Perigee: 360200 km
    22  Th   6:27 am  Moon Ascending Node
    25  Su  10:54 pm  Moon-Pleiades:  .1° S
    26  Mo   5:26 am  Last Quarter
    28  We   7:09 am  Moon North Dec.: 28.6° N
    30  Fr  12:47 am  Moon-Pollux: 1.8° N
    31  Sa   1:31 am  Moon-Beehive: 3.3° S
Sep  1  Su            Venus: 24.1° E

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 Events

     LU                  Ephemeris of Sky Events for Interlochen/TC
August, 2024    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Thu  1| 06:29a  09:07p  14:38 | 10:22p  05:14a |      Rise 04:03a    6%|
|Fri  2| 06:30a  09:06p  14:35 | 10:21p  05:15a |      Rise 05:12a    2%|
|Sat  3| 06:31a  09:05p  14:33 | 10:19p  05:17a |      Rise 06:22a    0%|
+------+-----------------------+----------------+-----------------------+
|Sun  4| 06:33a  09:03p  14:30 | 10:17p  05:18a |New   Set  09:37p    0%|
|Mon  5| 06:34a  09:02p  14:28 | 10:16p  05:20a |      Set  09:58p    2%|
|Tue  6| 06:35a  09:01p  14:25 | 10:14p  05:21a |      Set  10:15p    6%|
|Wed  7| 06:36a  08:59p  14:23 | 10:12p  05:23a |      Set  10:31p   11%|
|Thu  8| 06:37a  08:58p  14:20 | 10:10p  05:24a |      Set  10:47p   18%|
|Fri  9| 06:38a  08:56p  14:17 | 10:09p  05:26a |      Set  11:03p   26%|
|Sat 10| 06:40a  08:55p  14:15 | 10:07p  05:27a |      Set  11:21p   34%|
+------+-----------------------+----------------+-----------------------+
|Sun 11| 06:41a  08:53p  14:12 | 10:05p  05:29a |      Set  11:41p   44%|
|Mon 12| 06:42a  08:52p  14:09 | 10:03p  05:30a |F Qtr Set  12:07a   54%|
|Tue 13| 06:43a  08:50p  14:07 | 10:01p  05:32a |      Set  12:41a   63%|
|Wed 14| 06:44a  08:49p  14:04 | 09:59p  05:33a |      Set  01:25a   73%|
|Thu 15| 06:45a  08:47p  14:01 | 09:58p  05:35a |      Set  02:23a   82%|
|Fri 16| 06:47a  08:46p  13:58 | 09:56p  05:36a |      Set  03:34a   90%|
|Sat 17| 06:48a  08:44p  13:56 | 09:54p  05:38a |      Set  04:54a   95%|
+------+-----------------------+----------------+-----------------------+
|Sun 18| 06:49a  08:42p  13:53 | 09:52p  05:39a |      Set  06:18a   99%|
|Mon 19| 06:50a  08:41p  13:50 | 09:50p  05:41a |Full  Rise 09:02p  100%|
|Tue 20| 06:51a  08:39p  13:47 | 09:48p  05:42a |      Rise 09:25p   98%|
|Wed 21| 06:52a  08:37p  13:44 | 09:46p  05:43a |      Rise 09:46p   93%|
|Thu 22| 06:54a  08:36p  13:41 | 09:44p  05:45a |      Rise 10:07p   85%|
|Fri 23| 06:55a  08:34p  13:39 | 09:42p  05:46a |      Rise 10:29p   76%|
|Sat 24| 06:56a  08:32p  13:36 | 09:40p  05:48a |      Rise 10:54p   65%|
+------+-----------------------+----------------+-----------------------+
|Sun 25| 06:57a  08:30p  13:33 | 09:38p  05:49a |      Rise 11:26p   54%|
|Mon 26| 06:58a  08:29p  13:30 | 09:36p  05:51a |L Qtr Rise 12:06a   43%|
|Tue 27| 06:59a  08:27p  13:27 | 09:34p  05:52a |      Rise 12:55a   33%|
|Wed 28| 07:01a  08:25p  13:24 | 09:32p  05:53a |      Rise 01:55a   24%|
|Thu 29| 07:02a  08:23p  13:21 | 09:30p  05:55a |      Rise 03:02a   15%|
|Fri 30| 07:03a  08:22p  13:18 | 09:28p  05:56a |      Rise 04:11a    9%|
|Sat 31| 07:04a  08:20p  13:15 | 09:26p  05:58a |      Rise 05:20a    4%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

Generated using my LookingUp for DOS app.