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Posts Tagged ‘April 2021’

04/01/2021 – Ephemeris – Previewing April Skies

April 1, 2021 Comments off

This is Bob Moler with Ephemeris for Wednesday, March 31st. Today the Sun will be up for 12 hours and 44 minutes, setting at 8:09, and it will rise tomorrow at 7:23. The Moon, 3 days past full, will rise at 12:11 tomorrow morning.

Let’s search for the naked-eye planets for this week. Unfortunately the only one you’ll find in the evening is Mars. It can be found in the west-southwest at 9 pm tonight, above the orange star Aldebaran in the face of Taurus the bull. Mars will set at 1:54 am. Right now three of the other four naked eye planets are just west of the Sun in the Morning sky. Venus is now below and just a bit east of the Sun, setting four minutes after sunset. Only Saturn and Jupiter are at a far enough angle from the Sun to be just spotted in the morning twilight. Saturn will rise at 5:10 am, with Jupiter rising 31 minutes later. By 6:30 am they will be low in the southeast. The Sun is rising earlier by 2 minutes a day now, while sunset is nearly matching that pace in the opposite direction.

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

Addendum

April Evening Star Chart

April evening star chart
Star Chart for March 2021 (10 p.m. EDT April 15, 2021). Click on image to enlarge. Created using my LookingUp program. 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. The brilliant planet Venus is our Evening Star in the West at chart time. Note that Traverse City is located approximately 45 minutes behind our time meridian, West 75° longitude. (An hour and 45 minutes behind our daylight saving time meridian during EDT).

April Morning Star Chart

April morning star chart
Star Chart for April mornings 2021 (5 a.m. EDT April 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 appears in red.
  • LyrR is the radiant of the Lyrid meteor shower which will reach peak on the morning of the 22nd.
  • the 22nd.

Twilight Limits, Nautical and Astronomical

MorningTwilightEveningTwilightDarkNightMoon
DateAstro.NauticalNauticalAstro.StartEndIllum.
2021-04-015h46m6h23m21h18m21h54m21h54m0h11m0.74
2021-04-025h44m6h21m21h19m21h56m21h56m1h29m0.64
2021-04-035h42m6h19m21h20m21h57m21h57m2h42m0.52
2021-04-045h39m6h17m21h22m21h59m21h59m3h44m0.42
2021-04-055h37m6h15m21h23m22h01m22h01m4h35m0.31
2021-04-065h35m6h13m21h25m22h02m22h02m5h16m0.22
2021-04-075h33m6h11m21h26m22h04m22h04m5h33m0.14
2021-04-085h31m6h09m21h27m22h05m22h05m5h31m0.08
2021-04-095h28m6h07m21h29m22h07m22h07m5h28m0.03
2021-04-105h26m6h05m21h30m22h09m22h09m5h26m0.01
2021-04-115h24m6h03m21h32m22h10m22h10m5h24m0
2021-04-125h22m6h01m21h33m22h12m22h12m5h22m0.01
2021-04-135h20m5h59m21h35m22h14m22h14m5h20m0.04
2021-04-145h17m5h57m21h36m22h16m23h12m5h17m0.08
2021-04-155h15m5h55m21h38m22h17m5h15m0.14
2021-04-165h13m5h53m21h39m22h19m0h14m5h13m0.22
2021-04-175h11m5h51m21h41m22h21m1h15m5h11m0.3
2021-04-185h09m5h49m21h42m22h23m2h12m5h09m0.39
2021-04-195h06m5h47m21h44m22h24m3h03m5h06m0.49
2021-04-205h04m5h45m21h45m22h26m3h47m5h04m0.59
2021-04-215h02m5h43m21h47m22h28m4h25m5h02m0.7
2021-04-225h00m5h41m21h48m22h30m4h56m5h00m0.79
2021-04-234h57m5h39m21h50m22h32m0.88
2021-04-244h55m5h37m21h51m22h34m0.94
2021-04-254h53m5h35m21h53m22h35m0.99
2021-04-264h51m5h34m21h55m22h37m1
2021-04-274h49m5h32m21h56m22h39m0.98
2021-04-284h46m5h30m21h58m22h41m22h41m23h06m0.94
2021-04-294h44m5h28m21h59m22h43m22h43m0.87
2021-04-304h42m5h26m22h01m22h45m22h45m0h25m0.78

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      
Apr  1  Th            Venus: 2° E
     1  Th  10:41 pm  Moon Descending Node
     3  Sa  10:08 pm  Moon South Dec.: 25.4° S
     4  Su   6:02 am  Last Quarter
     6  Tu   4:34 am  Moon-Saturn: 4.2° N
     7  We   3:15 am  Moon-Jupiter: 4.7° N
    11  Su  10:31 pm  New Moon
    14  We   1:47 pm  Moon Apogee: 406100 km
    16  Fr   1:53 am  Moon Ascending Node
    17  Sa   8:09 am  Moon-Mars: 0.1° N, 
                         Occultation Africa-Asia
    18  Su  12:02 pm  Moon North Dec.: 25.5° N
    18  Su   9:31 pm  Mercury Superior Conj.
    20  Tu   2:59 am  First Quarter
    20  Tu   2:25 pm  Moon-Beehive: 3° S
    22  Th   8:16 am  Lyrid Shower: ZHR = 20
    26  Mo  11:31 pm  Full Moon - Supermoon
    27  Tu  11:24 am  Moon Perigee: 357400 km
    29  Th   5:17 am  Moon Descending Node
    30  Fr   5:15 pm  Uranus Conjunction
May  1  Sa            Venus: 9.4° E

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html.

Sun and Moon Rising and Setting Events

              Ephemeris of Sky Events for Interlochen/TC
April, 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| 07:23a  08:10p  12:47 | 09:15p  06:18a |      Rise 01:29a   76%|
|Fri  2| 07:21a  08:12p  12:50 | 09:17p  06:16a |      Rise 02:42a   66%|
|Sat  3| 07:19a  08:13p  12:53 | 09:18p  06:14a |      Rise 03:44a   55%|
+------+-----------------------+----------------+-----------------------+
|Sun  4| 07:17a  08:14p  12:56 | 09:19p  06:12a |L Qtr Rise 04:35a   44%|
|Mon  5| 07:15a  08:15p  13:00 | 09:21p  06:10a |      Rise 05:15a   33%|
|Tue  6| 07:13a  08:17p  13:03 | 09:22p  06:08a |      Rise 05:48a   24%|
|Wed  7| 07:12a  08:18p  13:06 | 09:24p  06:06a |      Rise 06:14a   16%|
|Thu  8| 07:10a  08:19p  13:09 | 09:25p  06:04a |      Rise 06:37a    9%|
|Fri  9| 07:08a  08:20p  13:12 | 09:27p  06:02a |      Rise 06:57a    4%|
|Sat 10| 07:06a  08:22p  13:15 | 09:28p  06:00a |      Rise 07:17a    1%|
+------+-----------------------+----------------+-----------------------+
|Sun 11| 07:05a  08:23p  13:18 | 09:30p  05:58a |New   Set  08:03p    0%|
|Mon 12| 07:03a  08:24p  13:21 | 09:31p  05:56a |      Set  09:05p    1%|
|Tue 13| 07:01a  08:25p  13:24 | 09:32p  05:54a |      Set  10:08p    3%|
|Wed 14| 06:59a  08:27p  13:27 | 09:34p  05:52a |      Set  11:11p    7%|
|Thu 15| 06:58a  08:28p  13:30 | 09:35p  05:50a |      Set  12:14a   13%|
|Fri 16| 06:56a  08:29p  13:33 | 09:37p  05:48a |      Set  01:15a   20%|
|Sat 17| 06:54a  08:30p  13:36 | 09:38p  05:46a |      Set  02:12a   28%|
+------+-----------------------+----------------+-----------------------+
|Sun 18| 06:52a  08:32p  13:39 | 09:40p  05:44a |      Set  03:03a   37%|
|Mon 19| 06:51a  08:33p  13:42 | 09:41p  05:42a |      Set  03:47a   47%|
|Tue 20| 06:49a  08:34p  13:44 | 09:43p  05:40a |F Qtr Set  04:24a   57%|
|Wed 21| 06:47a  08:35p  13:47 | 09:45p  05:38a |      Set  04:56a   67%|
|Thu 22| 06:46a  08:37p  13:50 | 09:46p  05:37a |      Set  05:24a   77%|
|Fri 23| 06:44a  08:38p  13:53 | 09:48p  05:35a |      Set  05:49a   86%|
|Sat 24| 06:43a  08:39p  13:56 | 09:49p  05:33a |      Set  06:14a   93%|
+------+-----------------------+----------------+-----------------------+
|Sun 25| 06:41a  08:40p  13:59 | 09:51p  05:31a |      Set  06:39a   98%|
|Mon 26| 06:39a  08:41p  14:02 | 09:52p  05:29a |Full  Rise 08:19p  100%|
|Tue 27| 06:38a  08:43p  14:04 | 09:54p  05:27a |      Rise 09:43p   99%|
|Wed 28| 06:36a  08:44p  14:07 | 09:55p  05:25a |      Rise 11:06p   95%|
|Thu 29| 06:35a  08:45p  14:10 | 09:57p  05:23a |      Rise 12:25a   88%|
|Fri 30| 06:33a  08:46p  14:13 | 09:59p  05:22a |      Rise 01:34a   80%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.