Archive
04/30/2021 – Ephemeris – Previewing May skies
This is Bob Moler with Ephemeris for Arbor Day, Friday, April 30th. Today the Sun will be up for 14 hours and 13 minutes, setting at 8:46, and it will rise tomorrow at 6:32. The Moon, 3 days before last quarter, will rise at 1:34 tomorrow morning.
The month of May starts tomorrow, when spring really gets going. Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 15 minutes tomorrow to 15 hours 19 minutes on the 31st. The altitude, or angle, of the Sun above the southern horizon at local noon will ascend from 61 degrees now to 67 degrees at month’s end. The altitude of the Sun in the Straits area will be a degree lower than that, but your daylight hours will be a few minutes longer. Local apparent noon this month, when the Sun passes due south, will be about 1:38 p.m. This is the month of the Eta Aquariid meteor shower which will reach its peak next week Thursday morning. There will be about a 2-hour viewing period starting at 3:15 am. We will get a chance to see the beginning of a lunar eclipse near sunrise on Wednesday the 26th.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
May Evening Star Chart
The planets and stars are plotted for the 15th at 11 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, 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 of 11 p.m. and 5 a.m. 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, or 28 minutes. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog for weekly positions.
May 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.
- 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,
- EaqR is the radiant of the Aquariid meteor shower that peaks on the 5th. Best viewing is before the peak this year due to the bright Moon.
Twilight Limits, Nautical and Astronomical
| EDT | |||||||
| Morning | Twilight | Evening | Twilight | Dark | Night | Moon | |
| Date | Astro. | Nautical | Nautical | Astro. | Start | End | Illum. |
| 2021-05-01 | 4h40m | 5h24m | 22h02m | 22h47m | 22h47m | 1h35m | 0.67 |
| 2021-05-02 | 4h38m | 5h23m | 22h04m | 22h49m | 22h49m | 2h32m | 0.57 |
| 2021-05-03 | 4h36m | 5h21m | 22h05m | 22h51m | 22h51m | 3h17m | 0.46 |
| 2021-05-04 | 4h33m | 5h19m | 22h07m | 22h53m | 22h53m | 3h52m | 0.36 |
| 2021-05-05 | 4h31m | 5h17m | 22h09m | 22h55m | 22h55m | 4h20m | 0.27 |
| 2021-05-06 | 4h29m | 5h16m | 22h10m | 22h57m | 22h57m | 4h29m | 0.18 |
| 2021-05-07 | 4h27m | 5h14m | 22h12m | 22h59m | 22h59m | 4h27m | 0.11 |
| 2021-05-08 | 4h25m | 5h12m | 22h13m | 23h01m | 23h01m | 4h25m | 0.06 |
| 2021-05-09 | 4h23m | 5h11m | 22h15m | 23h03m | 23h03m | 4h23m | 0.02 |
| 2021-05-10 | 4h21m | 5h09m | 22h16m | 23h05m | 23h05m | 4h21m | 0 |
| 2021-05-11 | 4h19m | 5h07m | 22h18m | 23h07m | 23h07m | 4h19m | 0 |
| 2021-05-12 | 4h17m | 5h06m | 22h19m | 23h09m | 23h09m | 4h17m | 0.02 |
| 2021-05-13 | 4h15m | 5h04m | 22h21m | 23h11m | 23h11m | 4h15m | 0.05 |
| 2021-05-14 | 4h13m | 5h03m | 22h23m | 23h13m | – | 4h13m | 0.1 |
| 2021-05-15 | 4h11m | 5h01m | 22h24m | 23h15m | 0h07m | 4h11m | 0.17 |
| 2021-05-16 | 4h09m | 5h00m | 22h26m | 23h17m | 1h00m | 4h09m | 0.25 |
| 2021-05-17 | 4h07m | 4h58m | 22h27m | 23h19m | 1h46m | 4h07m | 0.34 |
| 2021-05-18 | 4h05m | 4h57m | 22h28m | 23h21m | 2h25m | 4h05m | 0.44 |
| 2021-05-19 | 4h03m | 4h56m | 22h30m | 23h23m | 2h58m | 4h03m | 0.54 |
| 2021-05-20 | 4h01m | 4h54m | 22h31m | 23h24m | 3h26m | 4h01m | 0.65 |
| 2021-05-21 | 4h00m | 4h53m | 22h33m | 23h26m | 3h51m | 4h00m | 0.76 |
| 2021-05-22 | 3h58m | 4h52m | 22h34m | 23h28m | – | – | 0.85 |
| 2021-05-23 | 3h56m | 4h51m | 22h36m | 23h30m | – | – | 0.92 |
| 2021-05-24 | 3h54m | 4h49m | 22h37m | 23h32m | – | – | 0.98 |
| 2021-05-25 | 3h53m | 4h48m | 22h38m | 23h34m | – | – | 1 |
| 2021-05-26 | 3h51m | 4h47m | 22h40m | 23h36m | – | – | 0.99 |
| 2021-05-27 | 3h49m | 4h46m | 22h41m | 23h38m | – | – | 0.95 |
| 2021-05-28 | 3h48m | 4h45m | 22h42m | 23h39m | 23h39m | – | 0.89 |
| 2021-05-29 | 3h46m | 4h44m | 22h43m | 23h41m | 23h41m | 0h19m | 0.81 |
| 2021-05-30 | 3h45m | 4h43m | 22h45m | 23h43m | 23h43m | 1h11m | 0.72 |
| 2021-05-31 | 3h44m | 4h42m | 22h46m | 23h44m | 23h44m | 1h52m | 0.61 |
The twilight calendar was generated using Cartes du Ciel (Sky Charts), with some corrections.
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
May 1 Sa Venus: 9.4° E
1 Sa 5:37 am Moon South Dec.: 25.6° S
3 Mo 1:02 pm Moon-Saturn: 4.4° N
3 Mo 3:50 pm Last Quarter
3 Mo 11:01 pm Mercury-Pleiades: 2.2° S
4 Tu 5:00 pm Moon-Jupiter: 4.9° N
4 Tu 9:30 pm Eta Aquariid Shower: ZHR = 60
11 Tu 3:00 pm New Moon
11 Tu 5:54 pm Moon Apogee: 406500 km
13 Th 6:29 am Moon Ascending Node
13 Th 1:59 pm Moon-Mercury: 2.4° N
15 Sa 6:25 pm Moon North Dec.: 25.6° N
16 Su 12:47 am Moon-Mars: 1.6° S
17 Mo 1:59 am Mercury Elongation: 22° E
17 Mo 9:08 pm Moon-Beehive: 3.1° S
19 We 3:13 pm First Quarter
25 Tu 9:52 pm Moon Perigee: 357300 km
26 We 7:14 am Full Moon
26 We 7:19 am Total Lunar Eclipse (Start is visible here)
26 We 3:38 pm Moon Descending Node
28 Fr 3:21 pm Moon South Dec.: 25.6° S
28 Fr 11:01 pm Mercury-Venus: 0.4° N
30 Su 9:22 pm Moon-Saturn: 4.3° N
31 Mo 7:39 am Mars-Pollux: 5.3° S
Jun 1 Tu Venus: 17.5° 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
LU Ephemeris of Sky Events for Interlochen/TC May, 2021 Local time zone: EDT +-----------------------------------------------------------------------+ | DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM | | | RISE SET HOURS | END START |PHASE SET** TIME FRACTN| +=======================================================================+ |Sat 1| 06:32a 08:48p 14:15 | 10:00p 05:20a | Rise 02:32a 70%| +------+-----------------------+----------------+-----------------------+ |Sun 2| 06:30a 08:49p 14:18 | 10:02p 05:18a | Rise 03:17a 59%| |Mon 3| 06:29a 08:50p 14:21 | 10:03p 05:16a |L Qtr Rise 03:52a 48%| |Tue 4| 06:28a 08:51p 14:23 | 10:05p 05:14a | Rise 04:20a 38%| |Wed 5| 06:26a 08:53p 14:26 | 10:06p 05:13a | Rise 04:44a 28%| |Thu 6| 06:25a 08:54p 14:28 | 10:08p 05:11a | Rise 05:04a 20%| |Fri 7| 06:24a 08:55p 14:31 | 10:09p 05:09a | Rise 05:24a 13%| |Sat 8| 06:22a 08:56p 14:33 | 10:11p 05:08a | Rise 05:43a 7%| +------+-----------------------+----------------+-----------------------+ |Sun 9| 06:21a 08:57p 14:36 | 10:13p 05:06a | Rise 06:03a 3%| |Mon 10| 06:20a 08:58p 14:38 | 10:14p 05:04a | Rise 06:25a 1%| |Tue 11| 06:18a 09:00p 14:41 | 10:16p 05:03a |New Set 09:03p 0%| |Wed 12| 06:17a 09:01p 14:43 | 10:17p 05:01a | Set 10:06p 1%| |Thu 13| 06:16a 09:02p 14:45 | 10:19p 05:00a | Set 11:08p 4%| |Fri 14| 06:15a 09:03p 14:48 | 10:20p 04:58a | Set 12:07a 9%| |Sat 15| 06:14a 09:04p 14:50 | 10:22p 04:57a | Set 01:00a 15%| +------+-----------------------+----------------+-----------------------+ |Sun 16| 06:13a 09:05p 14:52 | 10:23p 04:55a | Set 01:46a 23%| |Mon 17| 06:12a 09:06p 14:54 | 10:25p 04:54a | Set 02:25a 32%| |Tue 18| 06:11a 09:08p 14:56 | 10:26p 04:52a | Set 02:57a 42%| |Wed 19| 06:10a 09:09p 14:59 | 10:28p 04:51a |F Qtr Set 03:26a 52%| |Thu 20| 06:09a 09:10p 15:01 | 10:29p 04:50a | Set 03:51a 63%| |Fri 21| 06:08a 09:11p 15:03 | 10:30p 04:48a | Set 04:14a 73%| |Sat 22| 06:07a 09:12p 15:04 | 10:32p 04:47a | Set 04:38a 83%| +------+-----------------------+----------------+-----------------------+ |Sun 23| 06:06a 09:13p 15:06 | 10:33p 04:46a | Set 05:04a 91%| |Mon 24| 06:05a 09:14p 15:08 | 10:35p 04:45a | Set 05:33a 97%| |Tue 25| 06:04a 09:15p 15:10 | 10:36p 04:44a | Set 06:09a 100%| |Wed 26| 06:04a 09:16p 15:12 | 10:37p 04:42a |Full Rise 09:57p 100%| |Thu 27| 06:03a 09:17p 15:13 | 10:39p 04:41a | Rise 11:14p 96%| |Fri 28| 06:02a 09:18p 15:15 | 10:40p 04:40a | Rise 12:19a 91%| |Sat 29| 06:01a 09:19p 15:17 | 10:41p 04:39a | Rise 01:11a 83%| +------+-----------------------+----------------+-----------------------+ |Sun 30| 06:01a 09:19p 15:18 | 10:42p 04:38a | Rise 01:52a 74%| |Mon 31| 06:00a 09:20p 15:19 | 10:43p 04:38a | Rise 02:23a 64%| +-----------------------------------------------------------------------+ * Nautical Twilight ** Moonrise or moonset, whichever occurs between sunrise and sunset
Generated using my LookingUp for DOS program.
Bob Moler's Ephemeris Blog 