Bob Moler's Ephemeris Blog

This is Ephemeris for April Fools’ Day, Tuesday, April 1st. Today the Sun will be up for 12 hours and 47 minutes, setting at 8:10, and it will rise tomorrow at 7:21. The Moon, halfway from new to first quarter, will set at 1:03 tomorrow morning.

The second quarter of the year begins today. Daylight hours in the Interlochen/Traverse City area and will increase from 12 hours and 47 minutes today to 14 hours 13 minutes on the 30th as spring really takes hold. The altitude, or angle, of the sun above the southern horizon at local noon will be 50 degrees today and will ascend to 60 degrees on April 3 The altitude of the Sun in the Straits area will be a degree lower. The actual time of local apparent noon at mid-month for the Interlochen/Traverse City area, when the sun passes due south, will be about 1:42 p.m. Jupiter and Mars will still be our evening planets this month. The Pleiades, tonight, will be just below the crescent Moon.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.

Addendum

April Evening Star Chart

The planets and stars are plotted for the 15th at 10 PM EST in the evening and 5 AM 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). To duplicate the star positions on a planisphere (rotating star finder) you may have to set it to 45 minutes or one hour 45 minutes (Daylight Time) earlier than the current time.

Note the chart times of 10 PM and 6 AM are for the 15th and 16th. For each week before these dates, add ½ hour (28 minutes if you’re picky). For each week after, subtract ½ hour. Planet positions on dates other than the 15/16th can be found in the Wednesday planet posts on this blog.

April Morning Star Chart

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.

Twilight Limits, Nautical and Astronomical

			EDT
	Morning	Twilight	Evening	Twilight	Dark	Night	Moon
Date	Astro.	Nautical	Nautical	Astro.	Start	End	Illum.
2025-04-01	5h42m	6h19m	21h18m	21h54m	–	5h42m	0.20
2025-04-02	5h40m	6h17m	21h19m	21h56m	1h03m	5h40m	0.30
2025-04-03	5h38m	6h15m	21h21m	21h57m	2h20m	5h38m	0.40
2025-04-04	5h36m	6h13m	21h22m	21h59m	3h23m	5h36m	0.51
2025-04-05	5h34m	6h11m	21h23m	22h01m	4h12m	5h34m	0.62
2025-04-06	5h32m	6h09m	21h25m	22h02m	4h49m	5h32m	0.71
2025-04-07	5h29m	6h07m	21h26m	22h04m	5h17m	5h29m	0.80
2025-04-08	5h27m	6h05m	21h28m	22h06m	–	–	0.87
2025-04-09	5h25m	6h03m	21h29m	22h07m	–	–	0.93
2025-04-10	5h23m	6h01m	21h31m	22h09m	–	–	0.97
2025-04-11	5h21m	5h59m	21h32m	22h11m	–	–	0.99
2025-04-12	5h18m	5h57m	21h34m	22h12m	–	–	1.00
2025-04-13	5h16m	5h55m	21h35m	22h14m	–	–	0.99
2025-04-14	5h14m	5h53m	21h36m	22h16m	22h16m	22h37m	0.96
2025-04-15	5h12m	5h51m	21h38m	22h17m	22h17m	23h43m	0.91
2025-04-16	5h09m	5h49m	21h39m	22h19m	22h19m	–	0.85
2025-04-17	5h07m	5h47m	21h41m	22h21m	22h21m	0h48m	0.78
2025-04-18	5h05m	5h45m	21h42m	22h23m	22h23m	1h48m	0.69
2025-04-19	5h03m	5h43m	21h44m	22h25m	22h25m	2h40m	0.59
2025-04-20	5h01m	5h41m	21h45m	22h26m	22h26m	3h23m	0.49
2025-04-21	4h58m	5h39m	21h47m	22h28m	22h28m	3h57m	0.38
2025-04-22	4h56m	5h38m	21h49m	22h30m	22h30m	4h25m	0.28
2025-04-23	4h54m	5h36m	21h50m	22h32m	22h32m	4h48m	0.18
2025-04-24	4h52m	5h34m	21h52m	22h34m	22h34m	4h52m	0.10
2025-04-25	4h50m	5h32m	21h53m	22h36m	22h36m	4h50m	0.04
2025-04-26	4h47m	5h30m	21h55m	22h37m	22h37m	4h47m	0.01
2025-04-27	4h45m	5h28m	21h56m	22h39m	22h39m	4h45m	0.00
2025-04-28	4h43m	5h26m	21h58m	22h41m	22h41m	4h43m	0.03
2025-04-29	4h41m	5h25m	21h59m	22h43m	23h56m	4h41m	0.09
2025-04-30	4h39m	5h23m	22h01m	22h45m	–	4h39m	0.16

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  Tu            Venus: 16.3° W
     1  Tu   4:28 PM  Moon-Pleiades: 0.6° S
     3  Th   6:15 PM  Moon North Dec.: 28.7° N
     4  Fr  10:14 PM  First Quarter
     5  Sa  12:46 PM  Moon-Pollux: 2.1° N
     5  Sa   3:04 PM  Moon-Mars: 2.3° S
     6  Su  12:44 PM  Moon-Beehive: 2.8° S
     8  Tu   7:51 AM  Moon-Regulus: 2.4° S
    10  Th   8:19 AM  Mercury-Saturn: 2.1° N
    10  Th   3:56 PM  Moon Descending Node
    12  Sa   8:22 PM  Full Moon
    12  Sa   9:39 PM  Moon-Spica: 0.4° N
    13  Su   6:48 PM  Moon Apogee: 406300 km
    16  We   6:19 PM  Moon-Antares: 0.4° N
    18  Fr   9:24 AM  Moon South Dec.: 28.6° S
    20  Su   9:35 PM  Last Quarter
    21  Mo   2:59 PM  Mercury Elongation: 27.4° W
    22  Tu   8:53 AM  Lyrid Shower: ZHR = 20
    24  Th   9:21 PM  Moon-Venus: 2.4° N
    24  Th  10:23 PM  Moon Ascending Node
    25  Fr  12:15 AM  Moon-Saturn: 2.3° S
    25  Fr   9:05 PM  Moon-Mercury: 4.3° S
    27  Su  12:15 PM  Moon Perigee: 357100 km
    27  Su   3:31 PM  New Moon
    28  Mo   3:27 PM  Venus-Saturn: 3.7° N
    29  Tu   2:35 AM  Moon-Pleiades: 0.5° S
May  1  Th            Venus: 40.9° W

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

LU                  Ephemeris of Sky Events for Interlochen/TC
April, 2025    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Tue  1| 07:23a  08:10p  12:47 | 09:15p  06:18a |      Set  01:03a   18%|
|Wed  2| 07:21a  08:12p  12:50 | 09:17p  06:16a |      Set  02:19a   27%|
|Thu  3| 07:19a  08:13p  12:53 | 09:18p  06:14a |      Set  03:23a   38%|
|Fri  4| 07:17a  08:14p  12:57 | 09:19p  06:12a |F Qtr Set  04:12a   49%|
|Sat  5| 07:15a  08:15p  13:00 | 09:21p  06:10a |      Set  04:48a   60%|
+------+-----------------------+----------------+-----------------------+
|Sun  6| 07:13a  08:17p  13:03 | 09:22p  06:08a |      Set  05:16a   69%|
|Mon  7| 07:12a  08:18p  13:06 | 09:24p  06:06a |      Set  05:38a   78%|
|Tue  8| 07:10a  08:19p  13:09 | 09:25p  06:04a |      Set  05:57a   86%|
|Wed  9| 07:08a  08:20p  13:12 | 09:27p  06:02a |      Set  06:13a   92%|
|Thu 10| 07:06a  08:22p  13:15 | 09:28p  06:00a |      Set  06:29a   96%|
|Fri 11| 07:04a  08:23p  13:18 | 09:30p  05:58a |      Set  06:44a   99%|
|Sat 12| 07:03a  08:24p  13:21 | 09:31p  05:56a |Full  Rise 08:25p  100%|
+------+-----------------------+----------------+-----------------------+
|Sun 13| 07:01a  08:25p  13:24 | 09:33p  05:54a |      Rise 09:30p   99%|
|Mon 14| 06:59a  08:27p  13:27 | 09:34p  05:52a |      Rise 10:36p   96%|
|Tue 15| 06:57a  08:28p  13:30 | 09:35p  05:50a |      Rise 11:43p   92%|
|Wed 16| 06:56a  08:29p  13:33 | 09:37p  05:48a |      Rise 12:48a   86%|
|Thu 17| 06:54a  08:30p  13:36 | 09:39p  05:46a |      Rise 01:48a   79%|
|Fri 18| 06:52a  08:32p  13:39 | 09:40p  05:44a |      Rise 02:40a   70%|
|Sat 19| 06:51a  08:33p  13:42 | 09:42p  05:42a |      Rise 03:22a   61%|
+------+-----------------------+----------------+-----------------------+
|Sun 20| 06:49a  08:34p  13:45 | 09:43p  05:40a |L Qtr Rise 03:57a   51%|
|Mon 21| 06:47a  08:35p  13:47 | 09:45p  05:38a |      Rise 04:25a   40%|
|Tue 22| 06:46a  08:37p  13:50 | 09:46p  05:36a |      Rise 04:48a   30%|
|Wed 23| 06:44a  08:38p  13:53 | 09:48p  05:35a |      Rise 05:09a   20%|
|Thu 24| 06:43a  08:39p  13:56 | 09:49p  05:33a |      Rise 05:29a   11%|
|Fri 25| 06:41a  08:40p  13:59 | 09:51p  05:31a |      Rise 05:50a    5%|
|Sat 26| 06:39a  08:42p  14:02 | 09:52p  05:29a |      Rise 06:14a    1%|
+------+-----------------------+----------------+-----------------------+
|Sun 27| 06:38a  08:43p  14:04 | 09:54p  05:27a |New   Set  09:05p    0%|
|Mon 28| 06:36a  08:44p  14:07 | 09:55p  05:25a |      Set  10:33p    2%|
|Tue 29| 06:35a  08:45p  14:10 | 09:57p  05:23a |      Set  11:56p    7%|
|Wed 30| 06:33a  08:46p  14:13 | 09:59p  05:22a |      Set  01:08a   15%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

Generated using my LookingUp for DOS program.