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Ephemeris: 05/10/2024 – Earthshine
This is Ephemeris for Friday, May 10th. Today the Sun will be up for 14 hours and 39 minutes, setting at 8:59, and it will rise tomorrow at 6:18. The Moon, 3 days past new, will set at 12:37 tomorrow morning.
The Moon tonight will appear as a thin sliver, with not much visible on the thin illuminated portion. However, if as you look at the moon tonight you have the funny feeling that the whole moon is visible, you are right. It’s easily confirmed with a pair of binoculars or a small telescope. What is illuminating the dark part of the Moon is earthshine. The Earth is big and bright in the Moon’s sky, and a fat waning gibbous from its vantage point. From the Moon the Earth has the opposite phase that we see of the Moon from the Earth. The effect used to be called by the term “Old moon in the new moon’s arms”. The effect was first explained by Leonardo da Vinci some 500 years ago. The effect will disappear in a few days as the Moon gets brighter and the Earth less so in the Moon’s sky. Earthshine will appear again when the Moon appears as a waning crescent in the morning. But not many of us are up to see it at that hour.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
Ephemeris: 05/09/2024 – How the Great Bear got her long tail
This is Ephemeris for Thursday, May 9th. Today the Sun will be up for 14 hours and 37 minutes, setting at 8:58, and it will rise tomorrow at 6:19. The Moon, 2 days past new, will set at 11:30 this evening.
As we see the Great Bear, Ursa Major in the sky with the Big Dipper as its hind end and tail, it seems apparent that the bear is unusual, because bears don’t have long tails. The peoples of the old world, Greeks and others, had a story of how the bear got his long tail. The God Zeus was responsible for the predicament that caused a young lady to be turned into the bear and placed her in the sky out of harm. Some question how he did this. To throw her into the sky, he probably didn’t want to grab the end with the teeth, so he grabbed the bear’s stubby tail whirled the bear around his head and threw her up into the sky where we see her today. Of course the tail was stretched. Some Native Americans did see a bear here too. But the three stars of the dipper’s handle were 3 hunters following the bear.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
For the story of why the young lady, Callisto, was turned into a bear, check out this post of a week ago: https://bobmoler.wordpress.com/2024/05/02/…
Ephemeris: 05/08/2024 – Saturn comes tottering into the morning twilight
This is Ephemeris for Wednesday, May 8th. Today the Sun will be up for 14 hours and 34 minutes, setting at 8:56, and it will rise tomorrow at 6:21. The Moon, 1 day past new, will set at 10:12 this evening.
Let’s find out where the naked-eye planets have wandered off to this week, and see what planets are left. Jupiter now is too close to the direction of the Sun to be seen. It will move to be in conjunction with the Sun on the 18th of this month and by late June may be visible in the morning sky in twilight. By 5:30 tomorrow morning, about 40 minutes before sunrise, Saturn will be low in the east-southeast and Mars will be lower yet in the east. In telescopes, Saturn will look fairly different this year and next with its rings nearly edge on to us. They will open up a bit through October before closing again. We won’t see the rings go exactly edge on because Saturn will be too close to the Sun in the sky on March 23rd next year. After that the rings will open up again.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
You may wonder why I use the word tottering in title. The planet Saturn is named after the Roman god of old age, probably because it takes nearly 30 years to orbit the Sun. Even though it’s moving away from twilight faster than Mars is, it’s just the fact that the Sun and Mars are moving faster to the east than it is, leaving him in the dust, so to speak.
Ephemeris: 05/07/2024 – Coma Berenices, a queen’s sacrifice
This is Ephemeris for Tuesday, May 7th. Today the Sun will be up for 14 hours and 32 minutes, setting at 8:55, and it will rise tomorrow at 6:22. The Moon is new today, and won’t be visible.
High in the south-southeast at 10:30 p.m. is a tiny and faint constellation of Coma Berenices, or Berenice’s Hair. In it are lots of faint stars arrayed to look like several strands of hair to the naked eye. The whole group will fit in the field of a pair of binoculars, which will also show many more stars. The story behind it was that Berenice was a real queen of Egypt, whose husband, the Pharaoh Ptolemy III, was away at war. This was in the days when the Greeks ruled Egypt after Alexander had conquered it. She offered her golden tresses to the gods for the king’s safe return. The hair, was placed in a temple. However, the offering disappeared when the king returned. Ever since then, the constellation of Coma Berenices has been seen to commemorate the queen’s sacrifice.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
Do not confuse the Coma Berenices star cluster (Melotte 111 and Collinder 256) with the Coma Cluster (actually a supercluster of galaxies up to 300 million light years away) in the northern part of the constellation. The Coma Cluster contains upwards of 10,000 galaxies.
Ephemeris: 05/06/2024 – The star Arcturus: Not from around here
This is Ephemeris for Monday, May 6th. Today the Sun will be up for 14 hours and 29 minutes, setting at 8:54, and it will rise tomorrow at 6:23. The Moon, 1 day before new, will rise at 5:53 tomorrow morning.
Arcturus, a red giant star in the constellation of Boötes the herdsman, is about two thirds the way up the sky in the east-southeast at 10 pm. It’s one of the earliest stars to appear in twilight, being nearly tied in brightness with Vega, a white star low in the northeast. A pointer to Arcturus is the handle of the Big Dipper, following the arc of the handle to Arcturus. Though only 37 light years away, it’s not from around here. It’s passing through the galactic disk from north to south. Arcturus is about 7 billion years old, and is about 8% more massive than our Sun. It appears to be starting its red giant phase, after running out of hydrogen to fuse into helium in its core, and is beginning to fuse the helium. It’s 25 times the size of the Sun and 170 times brighter, and a preview of our Sun when it gets that old.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
* Hertzsprung-Russell Diagram of a star’s surface (photosphere) temperature vs luminosity. The Main Sequence is where a star lives when it is burning hydrogen, and spends most of its life.
Ephemeris: 05/03/2024 – GTAS meeting tonight: Eclipse Tales
This is Ephemeris for Friday, May 3rd. Today the Sun will be up for 14 hours and 21 minutes, setting at 8:50, and it will rise tomorrow at 6:27. The Moon, 2 days past last quarter, will rise at 4:48 tomorrow morning.
The Grand Traverse Astronomical Society will meet this evening at 8:00 PM at the NMC’s Joseph Rogers observatory which is on Birmley Road, south of Traverse City. The program will consist of returning members from the total solar eclipse last month showing their photographs, and recounting their adventures of going down to the path of totality. And in my case a video of the changes in the sky at totality, as the Moon’s shadow passed over us. Afterward, if it’s clear, will be viewing the skies, though there will be no planets or the Moon out. In the morning hours before dawn tomorrow and Sunday morning there will be a meteor shower, the Eta Aquariid meteor shower of particles from Halley’s Comet striking the Earth’s atmosphere.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
There will be more photos and stories at the meeting.
Ephemeris: 05/02/2024 – All about the constellation of Boötes and Ursa Major
This is Ephemeris for Thursday, May 2nd. Today the Sun will be up for 14 hours and 19 minutes, setting at 8:49, and it will rise tomorrow at 6:29. The Moon, 1 day past last quarter, will rise at 4:27 tomorrow morning.
Seen in the east at 10:30 p.m. tonight is the kite shaped constellation of Boötes the herdsman. The bright star Arcturus is at the bottom of the kite to the right. It is pointed to by the arc of the handle of the Big Dipper, higher in the east. Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young lady who had the misfortune of being loved by Zeus the chief of the Greek gods. Zeus’ wife Hera, found out about it, and since she couldn’t punish Zeus, turned the poor woman into a bear. Arcas, many years later, unaware of the events surrounding his mother’s disappearance was about to kill the bear when Zeus intervened and placed them both in the sky to save her, as Arcas still pursues her across the sky nightly.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
Ephemeris: 05/01/2024 – Where are all naked eye planets?
This is Bob Moler with Ephemeris for Wednesday, May 1st. Today the Sun will be up for 14 hours and 16 minutes, setting at 8:48, and it will rise tomorrow at 6:30. The Moon, at last quarter today, will rise at 4:03 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week, and see what planets are left. Jupiter now is too close to the direction of the Sun to be seen. It will set at 9:49 pm. It will move to be in conjunction with the Sun on the 18th of this month and by late July may be visible in the morning sky in twilight. By 5:30 tomorrow morning, about an hour before sunrise, the Moon, Saturn and Mars will be visible low and spread out from the southeast to east. The fat waning crescent Moon will be highest in the southeast and to the left of it, and a bit lower, will be Saturn. Farther to the east, and lower yet will be dimmer Mars. In telescopes, Saturn will look fairly different this year and next with its rings nearly edge on to us.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
Ephemeris: 04/30/2024 – Previewing May Skies
This is Ephemeris for Tuesday, April 30th. Today the Sun will be up for 14 hours and 13 minutes, setting at 8:47, and it will rise tomorrow at 6:31. The Moon, 1 day before last quarter, will rise at 3:34 tomorrow morning.
The merry month of May starts tomorrow. Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 16 minutes tomorrow to 15 hours 20 minutes on the 31st. The altitude, or angle, of the Sun above the southern horizon at local noon will ascend from 60 degrees tomorrow to 67 degrees at month’s end. The altitude of the Sun in the Straits area will be a degree lower than that, but the daylight hours will be a few minutes longer. The evening sky in May is devoid of the Milky Way which nearly rings the horizon, so during this time we are looking out the thin side of the Milky Way towards intergalactic space. There is the Virgo cluster of galaxies, some of which are visible in decent size amateur telescopes.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). 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 4 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 4 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 Eta Aquariid meteor shower that peaks on the 5th.
Twilight Limits, Nautical and Astronomical
| EDT | |||||||
| Morning | Twilight | Evening | Twilight | Dark | Night | Moon | |
| Date | Astro. | Nautical | Nautical | Astro. | Start | End | Illum. |
| 2024-05-01 | 4h36m | 5h20m | 22h03m | 22h47m | 22h47m | 3h34m | 0.42 |
| 2024-05-02 | 4h34m | 5h19m | 22h04m | 22h49m | 22h49m | 4h03m | 0.31 |
| 2024-05-03 | 4h32m | 5h17m | 22h06m | 22h51m | 22h51m | 4h27m | 0.21 |
| 2024-05-04 | 4h29m | 5h15m | 22h08m | 22h53m | 22h53m | 4h29m | 0.12 |
| 2024-05-05 | 4h27m | 5h13m | 22h09m | 22h55m | 22h55m | 4h27m | 0.05 |
| 2024-05-06 | 4h25m | 5h12m | 22h11m | 22h57m | 22h57m | 4h25m | 0.01 |
| 2024-05-07 | 4h23m | 5h10m | 22h12m | 22h59m | 22h59m | 4h23m | 0.00 |
| 2024-05-08 | 4h21m | 5h08m | 22h14m | 23h01m | 23h01m | 4h21m | 0.02 |
| 2024-05-09 | 4h19m | 5h07m | 22h15m | 23h03m | 23h30m | 4h19m | 0.06 |
| 2024-05-10 | 4h17m | 5h05m | 22h17m | 23h05m | – | 4h17m | 0.12 |
| 2024-05-11 | 4h15m | 5h04m | 22h18m | 23h07m | 0h38m | 4h15m | 0.20 |
| 2024-05-12 | 4h13m | 5h02m | 22h20m | 23h09m | 1h32m | 4h13m | 0.28 |
| 2024-05-13 | 4h11m | 5h01m | 22h21m | 23h11m | 2h13m | 4h11m | 0.38 |
| 2024-05-14 | 4h09m | 4h59m | 22h23m | 23h13m | 2h44m | 4h09m | 0.47 |
| 2024-05-15 | 4h07m | 4h58m | 22h24m | 23h15m | 3h09m | 4h07m | 0.57 |
| 2024-05-16 | 4h05m | 4h56m | 22h26m | 23h17m | 3h28m | 4h05m | 0.66 |
| 2024-05-17 | 4h03m | 4h55m | 22h27m | 23h19m | 3h46m | 4h03m | 0.75 |
| 2024-05-18 | 4h01m | 4h53m | 22h29m | 23h21m | – | – | 0.82 |
| 2024-05-19 | 3h59m | 4h52m | 22h30m | 23h23m | – | – | 0.89 |
| 2024-05-20 | 3h58m | 4h51m | 22h32m | 23h25m | – | – | 0.94 |
| 2024-05-21 | 3h56m | 4h49m | 22h33m | 23h27m | – | – | 0.98 |
| 2024-05-22 | 3h54m | 4h48m | 22h35m | 23h29m | – | – | 1.00 |
| 2024-05-23 | 3h52m | 4h47m | 22h36m | 23h31m | – | – | 1.00 |
| 2024-05-24 | 3h51m | 4h46m | 22h37m | 23h32m | – | – | 0.97 |
| 2024-05-25 | 3h49m | 4h45m | 22h39m | 23h34m | 23h34m | – | 0.92 |
| 2024-05-26 | 3h47m | 4h44m | 22h40m | 23h36m | 23h36m | 0h07m | 0.86 |
| 2024-05-27 | 3h46m | 4h43m | 22h41m | 23h38m | 23h38m | 0h57m | 0.77 |
| 2024-05-28 | 3h44m | 4h42m | 22h43m | 23h40m | 23h40m | 1h36m | 0.67 |
| 2024-05-29 | 3h43m | 4h41m | 22h44m | 23h41m | 23h41m | 2h07m | 0.56 |
| 2024-05-30 | 3h42m | 4h40m | 22h45m | 23h43m | 23h43m | 2h31m | 0.45 |
| 2024-05-31 | 3h40m | 4h39m | 22h46m | 23h45m | 23h45m | 2h53m | 0.33 |
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 We Venus: 9.2° W
1 We 7:27 am Last Quarter
3 Fr 6:26 pm Moon-Saturn: .8° N
4 Sa 3:58 pm Eta Aquarid Shower: ZHR = 60
4 Sa 10:26 pm Moon-Mars: .2° S
5 Su 5:54 pm Moon Ascending Node
5 Su 6:11 pm Moon Perigee: 363200 km
6 Mo 4:25 am Moon-Mercury: 3.8° S
7 Tu 11:22 pm New Moon
9 Th 4:59 pm Mercury Elongation: 26.4° W
11 Sa 3:45 am Moon North Dec.: 28.5° N
12 Su 6:17 pm Moon-Pollux: 1.7° N
13 Mo 6:45 am Uranus Conjunction
13 Mo 6:47 pm Moon-Beehive: 3.7° S
15 We 7:48 am First Quarter
17 Fr 3:00 pm Moon Apogee: 404600 km
18 Sa 2:02 pm Jupiter Conjunction
19 Su 12:35 pm Moon Descending Node
20 Mo 5:20 am Moon-Spica: 1.5° S
23 Th 9:53 am Full Moon
23 Th 10:31 pm Moon-Antares: .4° S
25 Sa 3:58 pm Moon South Dec.: 28.4° S
30 Th 1:13 pm Last Quarter
31 Fr 4:01 am Moon-Saturn: .4° N
Jun 1 Sa Venus: .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
May, 2024 Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM |
| | RISE SET HOURS | END START |PHASE SET** TIME FRACTN|
+=======================================================================+
|Wed 1| 06:31a 08:48p 14:16 | 10:00p 05:19a |L Qtr Rise 04:03a 44%|
|Thu 2| 06:30a 08:49p 14:19 | 10:02p 05:18a | Rise 04:27a 33%|
|Fri 3| 06:29a 08:50p 14:21 | 10:04p 05:16a | Rise 04:48a 22%|
|Sat 4| 06:27a 08:52p 14:24 | 10:05p 05:14a | Rise 05:08a 13%|
+------+-----------------------+----------------+-----------------------+
|Sun 5| 06:26a 08:53p 14:27 | 10:07p 05:12a | Rise 05:29a 6%|
|Mon 6| 06:24a 08:54p 14:29 | 10:08p 05:11a | Rise 05:53a 2%|
|Tue 7| 06:23a 08:55p 14:32 | 10:10p 05:09a |New Set 08:50p 0%|
|Wed 8| 06:22a 08:56p 14:34 | 10:11p 05:07a | Set 10:12p 1%|
|Thu 9| 06:21a 08:58p 14:37 | 10:13p 05:06a | Set 11:30p 5%|
|Fri 10| 06:19a 08:59p 14:39 | 10:15p 05:04a | Set 12:37a 10%|
|Sat 11| 06:18a 09:00p 14:41 | 10:16p 05:02a | Set 01:31a 18%|
+------+-----------------------+----------------+-----------------------+
|Sun 12| 06:17a 09:01p 14:44 | 10:18p 05:01a | Set 02:12a 26%|
|Mon 13| 06:16a 09:02p 14:46 | 10:19p 04:59a | Set 02:44a 36%|
|Tue 14| 06:15a 09:03p 14:48 | 10:21p 04:58a | Set 03:08a 45%|
|Wed 15| 06:13a 09:05p 14:51 | 10:22p 04:56a |F Qtr Set 03:28a 55%|
|Thu 16| 06:12a 09:06p 14:53 | 10:24p 04:55a | Set 03:45a 64%|
|Fri 17| 06:11a 09:07p 14:55 | 10:25p 04:53a | Set 04:01a 73%|
|Sat 18| 06:10a 09:08p 14:57 | 10:27p 04:52a | Set 04:17a 81%|
+------+-----------------------+----------------+-----------------------+
|Sun 19| 06:09a 09:09p 14:59 | 10:28p 04:51a | Set 04:33a 88%|
|Mon 20| 06:08a 09:10p 15:01 | 10:29p 04:49a | Set 04:52a 93%|
|Tue 21| 06:07a 09:11p 15:03 | 10:31p 04:48a | Set 05:14a 97%|
|Wed 22| 06:07a 09:12p 15:05 | 10:32p 04:47a | Set 05:42a 100%|
|Thu 23| 06:06a 09:13p 15:07 | 10:34p 04:46a |Full Rise 09:58p 100%|
|Fri 24| 06:05a 09:14p 15:09 | 10:35p 04:44a | Rise 11:06p 98%|
|Sat 25| 06:04a 09:15p 15:10 | 10:36p 04:43a | Rise 12:07a 93%|
+------+-----------------------+----------------+-----------------------+
|Sun 26| 06:03a 09:16p 15:12 | 10:38p 04:42a | Rise 12:57a 87%|
|Mon 27| 06:03a 09:17p 15:14 | 10:39p 04:41a | Rise 01:36a 79%|
|Tue 28| 06:02a 09:18p 15:15 | 10:40p 04:40a | Rise 02:06a 69%|
|Wed 29| 06:01a 09:19p 15:17 | 10:41p 04:39a | Rise 02:31a 58%|
|Thu 30| 06:01a 09:20p 15:18 | 10:43p 04:38a |L Qtr Rise 02:52a 47%|
|Fri 31| 06:00a 09:21p 15:20 | 10:44p 04:37a | Rise 03:12a 35%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise
Ephemeris: 04/29/2024 – Corona Borealis, the Northern Crown
This is Ephemeris for Monday, April 29th. Today the Sun will be up for 14 hours and 11 minutes, setting at 8:46, and it will rise tomorrow at 6:33. The Moon, 2 days before last quarter, will rise at 2:58 tomorrow morning.
About a third of the way up the sky in the east at 10 p.m. can be found a small but easily spotted constellation of Corona Borealis, the Northern Crown. It is located just below the kite shaped constellation of Boötes, with its bright star Arcturus at the right. The Northern Crown is a three-quarter circle of stars, like a tiara, with a brighter star Alphecca at the bottom. Alphecca in Arabic means “The bright star of the broken ring of stars”, which is an accurate description of it. Check it out now for later this year we expect to have a bright star appear just below it. That star is T Coronae Borealis a recurrent Nova or exploding star. They occur when a white dwarf star is orbiting with a large red giant star and accumulating gas from that red giant star until it explodes.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). They may be different for your location.
Addendum
Bob Moler's Ephemeris Blog 
