08/01/2017 – Ephemeris – A look at the busy month of August in astronomy

Ephemeris for Tuesday, August 1st. The Sun rises at 6:29. It’ll be up for 14 hours and 38 minutes, setting at 9:07. The Moon, 2 days past first quarter, will set at 2:21 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. The Perseid meteor shower will reach its peak on the evening of the 12th. However the bright waning gibbous moon will rise just after 11:30 for a very short dark sky viewing period. The big event this month will be the total solar eclipse that will be visible from all 50 of the United States and total for a narrow strip of land stretching from Oregon to South Carolina. That will occur on the afternoon of Monday the 21st.

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

Addenda

August Evening Star Chart

Star Chart for August 2017 (10 p.m. August 15, 2017). Created using my LookingUp program. Click on image to enlarge.

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. (An hour 45 minutes behind our daylight saving time meridian. during EDT and 45 minutes behind our daylight standard time meridian. during EST). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes (Daylight Time) or 45 minutes (Standard Time) earlier than the current time if you are near your time meridian.

Note the chart times of 10 p.m. and 5 a.m. are for the 15th. For each week before the 15th add ½ hour. For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog.

August Morning Star Chart

Star Chart for August 2017 mornings based on 5 a.m. August 15th. Created using my LookingUp program. Click on image to enlarge.

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 Big Dipper drips on Leo
• Follow the arc of the handle of the Big Dipper to the star Arcturus,
• Then follow the Spike to Spica
• The Summer Triangle is in red
• PerR is the Perseid Meteor Shower radiant

Evening nautical twilight ends at 10:26 p.m. EDT on the 1st, decreasing to 9:30 p.m. EDT on the 31st.
Evening astronomical twilight ends at 11:15 p.m. EDT on the 1st, decreasing to 10:09 p.m. EDT on the 31st.
Morning astronomical twilight starts at 4:30 a.m. EDT on the 1st, and increasing to 5:24 a.m. EDT on the 31st.
Morning nautical twilight starts at 5:19 a.m. EDT on the 1st, and increasing to 6:03 a.m. EDT on the 31st.

NASA Calendar of Planetary Events

Date        Time    Event
Aug 01  Tu          Venus: 38.4° W
    02  We  1:55 pm Moon Apogee: 405000 km
    03  Th  3:31 am Moon-Saturn: 3.8° S
    04  Fr  2:17 pm Moon South Dec.: 19.4° S
    07  Mo  2:11 pm Full Moon
    07  Mo  2:22 pm Partial Lunar Eclipse (Not visible from here)
    08  Tu  6:56 am Moon Descending Node
    12  Sa  2:35 pm Perseid Shower: ZHR = 90
    14  Mo  9:15 pm Last Quarter
    16  We  2:39 am Moon-Aldebaran: 0.4° S
    18  Fr  2:50 am Moon North Dec.: 19.4° N
    18  Fr  9:14 am Moon Perigee: 366100 km
    19  Sa 12:45 am Moon-Venus: 2.3° N
    20  Su  3:15 am Moon-Beehive: 3.2° N
    21  Mo  6:34 am Moon Ascending Node
    21  Mo  2:26 pm Total Solar Eclipse
    21  Mo  2:30 pm New Moon
    25  Fr  9:00 am Moon-Jupiter: 3.7° S
    26  Sa  4:32 pm Mercury Inferior Conj.
    29  Tu  4:13 am First Quarter
    30  We  7:25 am Moon Apogee: 404300 km
    30  We 10:23 am Moon-Saturn: 3.9° S
    31  Th 10:03 pm Moon South Dec.: 19.4° S
Sep 01  Fr          Venus: 31.7° W

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.

August Rising and Setting Events

LU                  Ephemeris of Sky Events for Interlochen/TC
August, 2017    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Tue  1| 06:29a  09:08p  14:38 | 10:23p  05:13a |      Set  02:21a   72%|
|Wed  2| 06:30a  09:06p  14:36 | 10:21p  05:15a |      Set  03:00a   80%|
|Thu  3| 06:31a  09:05p  14:34 | 10:20p  05:16a |      Set  03:43a   87%|
|Fri  4| 06:32a  09:04p  14:31 | 10:18p  05:18a |      Set  04:32a   93%|
|Sat  5| 06:33a  09:02p  14:29 | 10:16p  05:19a |      Set  05:26a   97%|
+------+-----------------------+----------------+-----------------------+
|Sun  6| 06:34a  09:01p  14:26 | 10:15p  05:21a |      Set  06:24a   99%|
|Mon  7| 06:36a  09:00p  14:23 | 10:13p  05:22a |Full  Rise 09:01p  100%|
|Tue  8| 06:37a  08:58p  14:21 | 10:11p  05:24a |      Rise 09:35p   98%|
|Wed  9| 06:38a  08:57p  14:18 | 10:09p  05:25a |      Rise 10:06p   95%|
|Thu 10| 06:39a  08:55p  14:16 | 10:07p  05:27a |      Rise 10:36p   89%|
|Fri 11| 06:40a  08:54p  14:13 | 10:06p  05:28a |      Rise 11:06p   81%|
|Sat 12| 06:41a  08:52p  14:10 | 10:04p  05:30a |      Rise 11:36p   72%|
+------+-----------------------+----------------+-----------------------+
|Sun 13| 06:43a  08:51p  14:08 | 10:02p  05:31a |      Rise 12:09a   62%|
|Mon 14| 06:44a  08:49p  14:05 | 10:00p  05:33a |L Qtr Rise 12:46a   51%|
|Tue 15| 06:45a  08:48p  14:02 | 09:58p  05:34a |      Rise 01:28a   39%|
|Wed 16| 06:46a  08:46p  13:59 | 09:56p  05:36a |      Rise 02:16a   28%|
|Thu 17| 06:47a  08:44p  13:57 | 09:54p  05:37a |      Rise 03:13a   18%|
|Fri 18| 06:49a  08:43p  13:54 | 09:52p  05:39a |      Rise 04:16a   10%|
|Sat 19| 06:50a  08:41p  13:51 | 09:50p  05:40a |      Rise 05:24a    4%|
+------+-----------------------+----------------+-----------------------+
|Sun 20| 06:51a  08:39p  13:48 | 09:48p  05:42a |      Rise 06:35a    1%|
|Mon 21| 06:52a  08:38p  13:45 | 09:47p  05:43a |New   Set  08:44p    0%|
|Tue 22| 06:53a  08:36p  13:42 | 09:45p  05:44a |      Set  09:18p    2%|
|Wed 23| 06:54a  08:34p  13:39 | 09:43p  05:46a |      Set  09:49p    6%|
|Thu 24| 06:56a  08:33p  13:37 | 09:41p  05:47a |      Set  10:18p   12%|
|Fri 25| 06:57a  08:31p  13:34 | 09:39p  05:49a |      Set  10:46p   20%|
|Sat 26| 06:58a  08:29p  13:31 | 09:37p  05:50a |      Set  11:15p   28%|
+------+-----------------------+----------------+-----------------------+
|Sun 27| 06:59a  08:27p  13:28 | 09:35p  05:52a |      Set  11:46p   37%|
|Mon 28| 07:00a  08:26p  13:25 | 09:33p  05:53a |      Set  12:19a   47%|
|Tue 29| 07:01a  08:24p  13:22 | 09:31p  05:54a |F Qtr Set  12:56a   56%|
|Wed 30| 07:03a  08:22p  13:19 | 09:29p  05:56a |      Set  01:38a   65%|
|Thu 31| 07:04a  08:20p  13:16 | 09:27p  05:57a |      Set  02:24a   74%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise