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07/01/2021 – Ephemeris – Looking ahead at July’s skies

July 1, 2021 Comments off

This is Ephemeris for Thursday, July 1st. Today the Sun will be up for 15 hours and 30 minutes, setting at 9:32, and it will rise tomorrow at 6:01. The Moon, at last quarter today, will rise at 1:54 tomorrow morning.

Let’s preview July’s skies. The Sun, having reached its northern solstice, is beginning to slide southward again, at first imperceptibly, then with greater speed. The daylight hours will decrease from 15 hours and 30 minutes today to 14 hours 41 minutes at month’s end. The daylight hours will be slightly shorter south of Interlochen, and slightly longer to the north. The altitude of the Sun at local noon, when it is due south, will decrease from 68 degrees today to 63 degrees at month’s end. The Sun will be a degree lower in the Straits area. Despite the warmth, the Earth will reach its greatest distance from the Sun late Monday. That’s called aphelion where the Sun will be almost 94.5 million miles (152 million kilometers) away, which makes summer the longest season.

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

Addendum

July Evening Star Chart

July Evening Star Chart

Star Chart for July 2021 (11 p.m. EDT, July 15, 2021). Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 11 p.m. EDT in the evening and 4:30 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.

July Morning Star Chart

July Morning Star Chart

Star Chart for July mornings, 2021 (4:30 a.m. EDT July 15, 2021). 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 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.
  • DAqR is the radiant of the South Delta Aquariid meteor shower (Peaks on the 27th)

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning Twilight Evening Twilight Dark Night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2021-07-01 3h38m 4h41m 23h00m 0h03m 0h03m 1h35m 0.47
2021-07-02 3h39m 4h42m 22h59m 0h02m 0h02m 1h55m 0.37
2021-07-03 3h40m 4h42m 22h59m 0h01m 0h01m 2h14m 0.28
2021-07-04 3h41m 4h43m 22h58m 0h00m 0h00m 2h35m 0.2
2021-07-05 3h43m 4h44m 22h58m 23h59m 23h59m 2h57m 0.13
2021-07-06 3h44m 4h45m 22h57m 23h58m 23h58m 3h24m 0.07
2021-07-07 3h45m 4h46m 22h57m 23h57m 23h57m 3h45m 0.03
2021-07-08 3h47m 4h47m 22h56m 23h56m 23h56m 3h47m 0.01
2021-07-09 3h48m 4h48m 22h55m 23h55m 23h55m 3h48m 0
2021-07-10 3h50m 4h49m 22h54m 23h53m 23h53m 3h50m 0.01
2021-07-11 3h52m 4h50m 22h54m 23h52m 23h52m 3h52m 0.05
2021-07-12 3h53m 4h51m 22h53m 23h51m 23h51m 3h53m 0.1
2021-07-13 3h55m 4h53m 22h52m 23h49m 0h00m 3h55m 0.17
2021-07-14 3h57m 4h54m 22h51m 23h48m 3h57m 0.26
2021-07-15 3h58m 4h55m 22h50m 23h46m 0h23m 3h58m 0.37
2021-07-16 4h00m 4h56m 22h49m 23h45m 0h46m 4h00m 0.48
2021-07-17 4h02m 4h58m 22h47m 23h43m 1h08m 4h02m 0.59
2021-07-18 4h04m 4h59m 22h46m 23h41m 1h33m 4h04m 0.7
2021-07-19 4h06m 5h00m 22h45m 23h40m 2h01m 4h06m 0.8
2021-07-20 4h07m 5h02m 22h44m 23h38m 2h35m 4h07m 0.89
2021-07-21 4h09m 5h03m 22h43m 23h36m 3h18m 4h09m 0.95
2021-07-22 4h11m 5h04m 22h41m 23h34m 0.99
2021-07-23 4h13m 5h06m 22h40m 23h32m 1
2021-07-24 4h15m 5h07m 22h39m 23h31m 0.98
2021-07-25 4h17m 5h09m 22h37m 23h29m 0.94
2021-07-26 4h19m 5h10m 22h36m 23h27m 0.88
2021-07-27 4h21m 5h11m 22h34m 23h25m 23h25m 23h37m 0.81
2021-07-28 4h23m 5h13m 22h33m 23h23m 23h23m 23h58m 0.72
2021-07-29 4h25m 5h14m 22h31m 23h21m 23h21m 0.63
2021-07-30 4h27m 5h16m 22h30m 23h19m 23h19m 0h17m 0.53
2021-07-31 4h29m 5h17m 22h28m 23h17m 23h17m 0h38m 0.44

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
Jul  1  Th            Venus: 25.4° E
     1  Th   5:11 pm  Last Quarter
     2  Fr  10:45 pm  Venus-Beehive: 0.1° N
     4  Su   3:59 pm  Mercury Elongation: 21.6° W
     5  Mo  10:48 am  Moon Apogee: 405300 km
     5  Mo  10:59 pm  Aphelion: 1.0167 AU
     6  Tu   6:41 pm  Moon Ascending Node
     8  Th  12:38 am  Moon-Mercury: 4.1° S
     9  Fr   6:05 am  Moon North Dec.: 25.6° N
     9  Fr   9:16 pm  New Moon
    12  Mo   5:10 am  Moon-Venus: 3.5° S
    12  Mo   6:10 am  Moon-Mars: 4° S
    13  Tu   9:17 am  Venus-Mars: 0.5° N
    17  Sa   6:11 am  First Quarter
    20  Tu   9:22 am  Moon Descending Node
    21  We   6:30 am  Moon Perigee: 364500 km
    21  We   5:21 pm  Venus-Regulus: 1.1° N
    22  Th  11:12 am  Moon South Dec.: 25.6° S
    23  Fr  10:37 pm  Full Moon
    24  Sa  12:42 pm  Moon-Saturn: 3.9° N
    25  Su   9:17 pm  Moon-Jupiter: 4.3° N
    27  Tu  11:17 pm  Delta Aquariid Shower: ZHR = 20
    29  Th  10:09 am  Mars-Regulus: 0.6° N
    31  Sa   9:16 am  Last Quarter
Aug  1  Su            Venus: 33.1° 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 Events

LU                  Ephemeris of Sky Events for Interlochen/TC
July, 2021    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Thu  1| 06:01a  09:32p  15:30 | 10:57p  04:35a |L Qtr Rise 01:54a   49%|
|Fri  2| 06:01a  09:31p  15:29 | 10:56p  04:36a |      Rise 02:14a   39%|
|Sat  3| 06:02a  09:31p  15:29 | 10:56p  04:37a |      Rise 02:34a   30%|
+------+-----------------------+----------------+-----------------------+
|Sun  4| 06:03a  09:31p  15:28 | 10:55p  04:38a |      Rise 02:57a   22%|
|Mon  5| 06:03a  09:30p  15:27 | 10:55p  04:39a |      Rise 03:24a   15%|
|Tue  6| 06:04a  09:30p  15:26 | 10:54p  04:40a |      Rise 03:56a    9%|
|Wed  7| 06:05a  09:30p  15:24 | 10:53p  04:40a |      Rise 04:36a    4%|
|Thu  8| 06:05a  09:29p  15:23 | 10:53p  04:42a |      Rise 05:23a    1%|
|Fri  9| 06:06a  09:29p  15:22 | 10:52p  04:43a |New   Set  09:42p    0%|
|Sat 10| 06:07a  09:28p  15:21 | 10:51p  04:44a |      Set  10:26p    1%|
+------+-----------------------+----------------+-----------------------+
|Sun 11| 06:08a  09:28p  15:19 | 10:50p  04:45a |      Set  11:02p    4%|
|Mon 12| 06:09a  09:27p  15:18 | 10:49p  04:46a |      Set  11:33p    9%|
|Tue 13| 06:09a  09:26p  15:16 | 10:48p  04:47a |      Set  11:59p   16%|
|Wed 14| 06:10a  09:26p  15:15 | 10:47p  04:48a |      Set  12:23a   24%|
|Thu 15| 06:11a  09:25p  15:13 | 10:46p  04:49a |      Set  12:45a   34%|
|Fri 16| 06:12a  09:24p  15:11 | 10:45p  04:51a |      Set  01:08a   45%|
|Sat 17| 06:13a  09:23p  15:10 | 10:44p  04:52a |F Qtr Set  01:32a   57%|
+------+-----------------------+----------------+-----------------------+
|Sun 18| 06:14a  09:23p  15:08 | 10:43p  04:53a |      Set  02:00a   68%|
|Mon 19| 06:15a  09:22p  15:06 | 10:42p  04:55a |      Set  02:35a   78%|
|Tue 20| 06:16a  09:21p  15:04 | 10:40p  04:56a |      Set  03:18a   87%|
|Wed 21| 06:17a  09:20p  15:02 | 10:39p  04:57a |      Set  04:13a   94%|
|Thu 22| 06:18a  09:19p  15:00 | 10:38p  04:59a |      Set  05:18a   98%|
|Fri 23| 06:19a  09:18p  14:58 | 10:37p  05:00a |Full  Rise 09:35p  100%|
|Sat 24| 06:20a  09:17p  14:56 | 10:35p  05:02a |      Rise 10:16p   99%|
+------+-----------------------+----------------+-----------------------+
|Sun 25| 06:21a  09:16p  14:54 | 10:34p  05:03a |      Rise 10:49p   95%|
|Mon 26| 06:22a  09:15p  14:52 | 10:32p  05:04a |      Rise 11:15p   90%|
|Tue 27| 06:23a  09:14p  14:50 | 10:31p  05:06a |      Rise 11:37p   82%|
|Wed 28| 06:24a  09:13p  14:48 | 10:29p  05:07a |      Rise 11:58p   74%|
|Thu 29| 06:25a  09:11p  14:45 | 10:28p  05:09a |      Rise 12:17a   65%|
|Fri 30| 06:27a  09:10p  14:43 | 10:26p  05:10a |      Rise 12:38a   55%|
|Sat 31| 06:28a  09:09p  14:41 | 10:25p  05:12a |L Qtr Rise 01:00a   46%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset