11/30/2021 – Ephemeris – Previewing December skies

This is Ephemeris for Tuesday, November 30th. Today the Sun will be up for 9 hours and 4 minutes, setting at 5:03, and it will rise tomorrow at 8:00. The Moon, 3 days past last quarter, will rise at 4:24 tomorrow morning.

Let’s look ahead at the skies of December. We are now in the holiday season and about to celebrate the southernmost travel of the Sun in the sky and its return northward. The Sun will stop its travel south, the winter solstice on the 21st at 10:59 a.m. That will make that day the shortest day in terms of daylight hours. However, the earliest sunset and latest sunrise don’t coincide with that date. The reason is the Earth is closer to the Sun than average and is moving faster in its orbit than it normally does. It skews the sunrise and sunset times, making them later than they would be on average. We have a comet, C/2021 A1 (Leonard), that will be bright enough to be visible in binoculars coming into view in the morning later this week and into the next.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

December Evening Star Chart

Star Chart for December 2021 (9 p.m. EST December 15, 2021). Click on image to enlarge. Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 9 pm EST in the evening and 6 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).

December Morning Star Chart

Star Chart for December mornings, 2021 (6 a.m. EST December 15, 2021). 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.
• The leaky bowl of the 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.
• GemR on the star charts is the radiant of the Geminid meteor shower, which peaks on the morning of the 14th.

Twilight Limits, Nautical and Astronomical

			EST
	Morning	Twilight	Evening	Twilight	Dark	Night	Moon
Date	Astro.	Nautical	Nautical	Astro.	Start	End	Illum.
2021-12-01	6h20m	6h56m	18h15m	18h51m	18h51m	4h24m	0.07
2021-12-02	6h21m	6h57m	18h15m	18h50m	18h50m	5h45m	0.02
2021-12-03	6h22m	6h57m	18h15m	18h50m	18h50m	6h22m	0
2021-12-04	6h23m	6h58m	18h15m	18h50m	18h50m	6h23m	0.01
2021-12-05	6h24m	6h59m	18h15m	18h50m	18h50m	6h24m	0.05
2021-12-06	6h25m	7h00m	18h15m	18h50m	19h27m	6h25m	0.12
2021-12-07	6h26m	7h01m	18h15m	18h50m	20h43m	6h26m	0.21
2021-12-08	6h27m	7h02m	18h15m	18h50m	22h00m	6h27m	0.31
2021-12-09	6h28m	7h03m	18h15m	18h50m	23h14m	6h28m	0.41
2021-12-10	6h28m	7h04m	18h15m	18h50m	–	6h28m	0.52
2021-12-11	6h29m	7h05m	18h15m	18h50m	0h25m	6h29m	0.62
2021-12-12	6h30m	7h05m	18h15m	18h51m	1h32m	6h30m	0.71
2021-12-13	6h31m	7h06m	18h15m	18h51m	2h38m	6h31m	0.79
2021-12-14	6h31m	7h07m	18h16m	18h51m	3h42m	6h31m	0.87
2021-12-15	6h32m	7h07m	18h16m	18h51m	4h46m	6h32m	0.92
2021-12-16	6h33m	7h08m	18h16m	18h52m	5h50m	6h33m	0.97
2021-12-17	6h29m	7h05m	18h13m	18h48m	–	–	0.99
2021-12-18	6h30m	7h05m	18h13m	18h48m	–	–	1
2021-12-19	6h30m	7h06m	18h13m	18h49m	–	–	0.99
2021-12-20	6h31m	7h07m	18h14m	18h49m	–	–	0.96
2021-12-21	6h31m	7h07m	18h14m	18h50m	18h50m	19h11m	0.92
2021-12-22	6h32m	7h07m	18h15m	18h50m	18h50m	20h16m	0.86
2021-12-23	6h32m	7h08m	18h15m	18h51m	18h51m	21h23m	0.78
2021-12-24	6h33m	7h08m	18h16m	18h51m	18h51m	22h31m	0.7
2021-12-25	6h33m	7h09m	18h17m	18h52m	18h52m	23h40m	0.6
2021-12-26	6h34m	7h09m	18h17m	18h53m	18h53m	–	0.49
2021-12-27	6h34m	7h09m	18h18m	18h53m	18h53m	0h50m	0.38
2021-12-28	6h34m	7h10m	18h19m	18h54m	18h54m	2h02m	0.27
2021-12-29	6h34m	7h10m	18h19m	18h55m	18h55m	3h18m	0.18
2021-12-30	6h35m	7h10m	18h20m	18h55m	18h55m	4h38m	0.1
2021-12-31	6h35m	7h10m	18h21m	18h56m	18h56m	6h00m	0.04

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
Dec  1  We            Venus: 41.4° E
     3  Fr   9:58 am  Moon Descending Node
     4  Sa   2:34 am  Total Solar Eclipse (Antarctica, Southern Ocean)
     4  Sa   2:43 am  New Moon
     4  Sa   5:01 am  Moon Perigee: 356800 km
     5  Su   9:25 pm  Moon South Dec.: 26.3° S
     6  Mo   7:48 pm  Moon-Venus: 1.9° N
     7  Tu   8:52 pm  Moon-Saturn: 4.2° N
     9  Th   1:07 am  Moon-Jupiter: 4.6° N
    10  Fr   8:36 pm  First Quarter
    14  Tu   1:44 am  Geminid Shower: ZHR = 120
    16  Th   7:12 pm  Moon Ascending Node
    17  Fr   9:16 pm  Moon Apogee: 406300 km
    18  Sa  11:36 pm  Full Moon
    19  Su  11:32 pm  Moon North Dec.: 26.3° N
    21  Tu   4:20 am  Moon-Pollux: 2.9° N
    21  Tu  10:59 am  Winter Solstice
    22  We   5:28 am  Moon-Beehive: 3.6° S
    22  We  10:00 am  Ursid Shower: ZHR = 10
    26  Su   9:24 pm  Last Quarter
    27  Mo   4:17 am  Mars-Antares: 4.5° N
    28  Tu  11:49 pm  Mercury-Venus: 4.2° N
    30  Th   8:07 pm  Moon Descending Node
    31  Fr   3:13 pm  Moon-Mars: 0.9° N

All event times are given for UTC-5 Eastern Standard 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
December, 2021    Local time zone: EST
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Wed  1| 08:00a  05:03p  09:03 | 06:12p  06:50a |      Rise 05:45a    8%|
|Thu  2| 08:01a  05:03p  09:01 | 06:12p  06:51a |      Rise 07:09a    3%|
|Fri  3| 08:02a  05:02p  09:00 | 06:12p  06:52a |      Rise 08:33a    0%|
|Sat  4| 08:03a  05:02p  08:59 | 06:12p  06:53a |New   Set  05:18p    1%|
+------+-----------------------+----------------+-----------------------+
|Sun  5| 08:04a  05:02p  08:57 | 06:12p  06:54a |      Set  06:17p    4%|
|Mon  6| 08:05a  05:02p  08:56 | 06:12p  06:55a |      Set  07:27p   11%|
|Tue  7| 08:06a  05:02p  08:55 | 06:12p  06:56a |      Set  08:43p   19%|
|Wed  8| 08:07a  05:02p  08:54 | 06:12p  06:57a |      Set  10:00p   28%|
|Thu  9| 08:08a  05:02p  08:53 | 06:12p  06:58a |      Set  11:14p   39%|
|Fri 10| 08:09a  05:02p  08:52 | 06:12p  06:59a |F Qtr Set  12:25a   49%|
|Sat 11| 08:10a  05:02p  08:51 | 06:12p  06:59a |      Set  01:32a   60%|
+------+-----------------------+----------------+-----------------------+
|Sun 12| 08:11a  05:02p  08:51 | 06:12p  07:00a |      Set  02:37a   69%|
|Mon 13| 08:11a  05:02p  08:50 | 06:12p  07:01a |      Set  03:41a   78%|
|Tue 14| 08:12a  05:02p  08:49 | 06:13p  07:02a |      Set  04:45a   85%|
|Wed 15| 08:13a  05:02p  08:49 | 06:13p  07:02a |      Set  05:50a   91%|
|Thu 16| 08:14a  05:03p  08:49 | 06:13p  07:03a |      Set  06:53a   96%|
|Fri 17| 08:14a  05:03p  08:48 | 06:14p  07:04a |      Set  07:56a   99%|
|Sat 18| 08:15a  05:03p  08:48 | 06:14p  07:04a |Full  Rise 04:34p  100%|
+------+-----------------------+----------------+-----------------------+
|Sun 19| 08:16a  05:04p  08:48 | 06:14p  07:05a |      Rise 05:19p   99%|
|Mon 20| 08:16a  05:04p  08:48 | 06:15p  07:05a |      Rise 06:12p   97%|
|Tue 21| 08:17a  05:05p  08:48 | 06:15p  07:06a |      Rise 07:11p   93%|
|Wed 22| 08:17a  05:05p  08:48 | 06:16p  07:06a |      Rise 08:16p   87%|
|Thu 23| 08:18a  05:06p  08:48 | 06:16p  07:07a |      Rise 09:23p   80%|
|Fri 24| 08:18a  05:06p  08:48 | 06:17p  07:07a |      Rise 10:31p   71%|
|Sat 25| 08:18a  05:07p  08:48 | 06:18p  07:08a |      Rise 11:40p   62%|
+------+-----------------------+----------------+-----------------------+
|Sun 26| 08:19a  05:08p  08:49 | 06:18p  07:08a |L Qtr Rise 12:50a   51%|
|Mon 27| 08:19a  05:08p  08:49 | 06:19p  07:08a |      Rise 02:02a   40%|
|Tue 28| 08:19a  05:09p  08:50 | 06:20p  07:09a |      Rise 03:18a   30%|
|Wed 29| 08:19a  05:10p  08:50 | 06:20p  07:09a |      Rise 04:37a   20%|
|Thu 30| 08:19a  05:11p  08:51 | 06:21p  07:09a |      Rise 06:00a   11%|
|Fri 31| 08:20a  05:12p  08:52 | 06:22p  07:09a |      Rise 07:20a    5%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

Comet Leonard

Comet Leonard’s positions at 6:30 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for November 27th. The star field will be shifting to the upper right each morning at 6:30 from the November 27th date. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. Plus, the comet tails will not appear as long. The tail may not actually be visible visually. Created using Cartes du Ciel (Sky Charts). Reprinted from my article in the December 2021 issue of the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society.

This is our best shot at spotting the comet. After it passes the Sun and enters the evening sky, the comet will hug the southwest to southern horizon in twilight. I’ll have more on Comet Leonard in the rest of the programs this week.