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07/31/2020 – Ephemeris – Previewing August skies

July 31, 2020 Comments off

This is Bob Moler with Ephemeris for Friday, July 31st. Today the Sun will be up for 14 hours and 40 minutes, setting at 9:09, and it will rise tomorrow at 6:29. The Moon, 3 days before full, will set at 4:04 tomorrow morning.

Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 38 minutes tomorrow 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 tomorrow 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 late evening sky: The Perseid meteor shower will be best seen on the evening of the 11th before the Moon rises at 12:46 am. August is the first of my two favorite months for viewing the wonders of the summer Milky Way.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

August Evening Star Chart

August 2020 Evening Star Chart_2200-081520

Star Chart for August 2020 (10 p.m. EDT August 15, 2020). Click on image to enlarge. Created using my LookingUp program.

The planets and stars are plotted for the 15th at 10 p.m. EDT in the evening and 5 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.

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. For planet positions on dates other than the 15th.

August Morning Star Chart

August Morning Star Chart

Star Chart for August mornings 2020 (5 a.m. EDT August 15, 2020). Click on image to enlarge. Created using my LookingUp program.

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 12th)

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning twilight Evening twilight Dark night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2020-08-01 4h31m 5h19m 22h26m 23h14m 4h04m 4h31m 0.93
2020-08-02 4h33m 5h21m 22h24m 23h12m – – 0.98
2020-08-03 4h35m 5h22m 22h23m 23h10m – – 1
2020-08-04 4h37m 5h24m 22h21m 23h08m – – 1
2020-08-05 4h39m 5h25m 22h19m 23h06m – – 0.97
2020-08-06 4h41m 5h27m 22h18m 23h04m – – 0.93
2020-08-07 4h43m 5h28m 22h16m 23h01m 23h01m 23h16m 0.87
2020-08-08 4h44m 5h30m 22h14m 22h59m 22h59m 23h36m 0.8
2020-08-09 4h46m 5h31m 22h12m 22h57m 22h57m 23h57m 0.71
2020-08-10 4h48m 5h33m 22h10m 22h55m 22h55m – 0.62
2020-08-11 4h50m 5h34m 22h09m 22h53m 22h53m 0h20m 0.52
2020-08-12 4h52m 5h36m 22h07m 22h51m 22h51m 0h46m 0.42
2020-08-13 4h54m 5h37m 22h05m 22h48m 22h48m 1h16m 0.33
2020-08-14 4h56m 5h39m 22h03m 22h46m 22h46m 1h53m 0.23
2020-08-15 4h57m 5h40m 22h01m 22h44m 22h44m 2h39m 0.15
2020-08-16 4h59m 5h42m 21h59m 22h42m 22h42m 3h35m 0.08
2020-08-17 5h01m 5h43m 21h57m 22h39m 22h39m 4h40m 0.03
2020-08-18 5h03m 5h45m 21h55m 22h37m 22h37m 5h03m 0
2020-08-19 5h05m 5h46m 21h53m 22h35m 22h35m 5h05m 0.01
2020-08-20 5h06m 5h48m 21h52m 22h33m 22h33m 5h06m 0.04
2020-08-21 5h08m 5h49m 21h50m 22h30m 22h30m 5h08m 0.1
2020-08-22 5h10m 5h50m 21h48m 22h28m 22h53m 5h10m 0.19
2020-08-23 5h12m 5h52m 21h46m 22h26m 23h20m 5h12m 0.29
2020-08-24 5h13m 5h53m 21h44m 22h24m 23h51m 5h13m 0.41
2020-08-25 5h15m 5h55m 21h42m 22h22m – 5h15m 0.53
2020-08-26 5h17m 5h56m 21h40m 22h19m 0h27m 5h17m 0.64
2020-08-27 5h18m 5h58m 21h38m 22h17m 1h09m 5h18m 0.75
2020-08-28 5h20m 5h59m 21h36m 22h15m 1h59m 5h20m 0.83
2020-08-29 5h22m 6h00m 21h34m 22h13m 2h56m 5h22m 0.91
2020-08-30 5h23m 6h02m 21h32m 22h10m 3h58m 5h23m 0.91
2020-08-31 5h25m 6h03m 21h30m 22h08m 5h04m 5h25m 0.96

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  Sa            Venus: 45.2° W
    1  Sa  04:47 am  Moon South Dec.: 24.1° S
    1  Sa  04:14 pm  Mercury-Pollux: 6.7° S
    1  Sa  07:30 pm  Moon-Jupiter: 1.6° N
    2  Su  09:17 am  Moon-Saturn: 2.4° N
    3  Mo  11:59 am  Full Moon
    9  Su  03:57 am  Moon-Mars: 0.8° N
    9  Su  09:51 am  Moon Apogee: 404700 km
   11  Tu  12:45 pm  Last Quarter
   12  We  09:02 am  Perseid Meteor Shower: ZHR = 90
   12  We  08:59 pm  Venus Greatest Elongation: 45.8° W
   14  Fr  03:22 pm  Moon Ascending Node
   15  Sa  09:01 am  Moon-Venus: 4.2° S
   15  Sa  04:40 pm  Moon North Dec.: 24.2° N
   17  Mo  10:47 am  Mercury Superior Solar Conjunction
   18  Tu  10:41 pm  New Moon
   21  Fr  06:59 am  Moon Perigee: 363500 km
   25  Tu  01:58 pm  First Quarter
   27  Th  07:52 am  Moon Descending Node
   28  Fr  10:06 am  Moon South Dec.: 24.2° S
   28  Fr  09:33 pm  Moon-Jupiter: 1.5° N
   29  Sa  12:40 pm  Moon-Saturn: 2.3° N
Sep 1  Tu            Venus: 44.7° W
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 Events

LU              Ephemeris of Sky Events for Interlochen/TC
August, 2020    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Sat  1| 06:29a  09:07p  14:38 | 10:23p  05:14a |      Set  05:04a   97%|
+------+-----------------------+----------------+-----------------------+
|Sun  2| 06:30a  09:06p  14:35 | 10:21p  05:15a |      Set  06:09a   99%|
|Mon  3| 06:31a  09:05p  14:33 | 10:19p  05:17a |Full  Rise 09:35p  100%|
|Tue  4| 06:33a  09:03p  14:30 | 10:17p  05:18a |      Rise 10:06p   98%|
|Wed  5| 06:34a  09:02p  14:28 | 10:16p  05:20a |      Rise 10:32p   94%|
|Thu  6| 06:35a  09:01p  14:25 | 10:14p  05:21a |      Rise 10:55p   89%|
|Fri  7| 06:36a  08:59p  14:23 | 10:12p  05:23a |      Rise 11:16p   82%|
|Sat  8| 06:37a  08:58p  14:20 | 10:10p  05:24a |      Rise 11:36p   75%|
+------+-----------------------+----------------+-----------------------+
|Sun  9| 06:38a  08:56p  14:18 | 10:09p  05:26a |      Rise 11:57p   66%|
|Mon 10| 06:39a  08:55p  14:15 | 10:07p  05:27a |      Rise 12:20a   57%|
|Tue 11| 06:41a  08:53p  14:12 | 10:05p  05:29a |L Qtr Rise 12:46a   47%|
|Wed 12| 06:42a  08:52p  14:10 | 10:03p  05:30a |      Rise 01:16a   38%|
|Thu 13| 06:43a  08:50p  14:07 | 10:01p  05:32a |      Rise 01:53a   28%|
|Fri 14| 06:44a  08:49p  14:04 | 09:59p  05:33a |      Rise 02:39a   20%|
|Sat 15| 06:45a  08:47p  14:01 | 09:58p  05:35a |      Rise 03:35a   12%|
+------+-----------------------+----------------+-----------------------+
|Sun 16| 06:46a  08:46p  13:59 | 09:56p  05:36a |      Rise 04:40a    6%|
|Mon 17| 06:48a  08:44p  13:56 | 09:54p  05:38a |      Rise 05:53a    2%|
|Tue 18| 06:49a  08:42p  13:53 | 09:52p  05:39a |New   Set  08:58p    0%|
|Wed 19| 06:50a  08:41p  13:50 | 09:50p  05:40a |      Set  09:30p    1%|
|Thu 20| 06:51a  08:39p  13:47 | 09:48p  05:42a |      Set  09:59p    5%|
|Fri 21| 06:52a  08:37p  13:44 | 09:46p  05:43a |      Set  10:26p   12%|
|Sat 22| 06:54a  08:36p  13:42 | 09:44p  05:45a |      Set  10:52p   20%|
+------+-----------------------+----------------+-----------------------+
|Sun 23| 06:55a  08:34p  13:39 | 09:42p  05:46a |      Set  11:20p   30%|
|Mon 24| 06:56a  08:32p  13:36 | 09:40p  05:48a |      Set  11:51p   42%|
|Tue 25| 06:57a  08:30p  13:33 | 09:38p  05:49a |F Qtr Set  12:26a   53%|
|Wed 26| 06:58a  08:29p  13:30 | 09:36p  05:51a |      Set  01:09a   64%|
|Thu 27| 06:59a  08:27p  13:27 | 09:34p  05:52a |      Set  01:58a   74%|
|Fri 28| 07:01a  08:25p  13:24 | 09:32p  05:53a |      Set  02:56a   83%|
|Sat 29| 07:02a  08:23p  13:21 | 09:30p  05:55a |      Set  03:58a   90%|
+------+-----------------------+----------------+-----------------------+
|Sun 30| 07:03a  08:22p  13:18 | 09:28p  05:56a |      Set  05:04a   95%|
|Mon 31| 07:04a  08:20p  13:15 | 09:26p  05:58a |      Set  06:10a   98%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

Categories: Ephemeris Program, Month preview Tags: