Archive
05/12/2023 – Ephemeris – Finding Virgo the virgin in the evening sky
This is Ephemeris for Friday, May 12th. Today the Sun will be up for 14 hours and 42 minutes, setting at 9:00, and it will rise tomorrow at 6:17. The Moon, at last quarter today, will rise at 3:44 tomorrow morning.
One of the large constellations we see in the south at 11 p.m. can be found using the Big Dipper overhead, follow the arc of the handle to the bright star Arcturus, then straighten the arc to a spike to reach Spica, a bright blue-white star in the south. Spica is the brightest star in the constellation Virgo, the virgin. She represents the goddess of the harvest, Virgo is holding a sheaf of wheat in depictions of her, and Spica is placed at the head of the sheaf. In the space between Spica and Leo the lion to her upper right is, a great cluster of thousands of galaxies just below naked eye visibility. The Virgo Cluster. Inside that cluster is galaxy M87, in whose center lies a black hole with the mass of 6.5 billion suns. The center of the cluster is at about 54 million light years away.
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

Finding Virgo from the Big Dipper at 11 pm, May 12. There are no planetary interlopers this year. The small + sign marks the zenith, and the image faces south. Created using my LookingUp app, with captions added using LibreOffice Draw.
05/11/2023 – Ephemeris – Finding Hydra the water snake
This is Ephemeris for Thursday, May 11th. Today the Sun will be up for 14 hours and 40 minutes, setting at 8:59, and it will rise tomorrow at 6:18. The Moon, 1 day before last quarter, will rise at 3:17 tomorrow morning.
Low in the south and southwestern sky at 10 p.m. and later can be found the constellation of Hydra the water snake, the longest constellation of all. Unlike the monster of the same name, this Hydra has but one head, which is its most distinctive part. At 11 p.m. the head of Hydra is located between the bright stars Procyon in the west and Regulus in Leo the lion in the southwest. Hydra’s head is a small but distinctive group of 6 stars that make a drooping loop to the right. The rest of Hydra wends its way above the southern horizon below the bright blue star Spica in Virgo. Some delineations of Hydra have the tail tickling the constellation Libra, the balance which has just risen in the southeast.
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
05/10/2023 – Ephemeris – Let’s find where the naked-eye planets have wandered off to this week
This is Bob Moler with Ephemeris for Wednesday, May 10th. 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 before last quarter, will rise at 2:42 tomorrow morning.
Let’s find where the naked-eye planets have wandered off to this week. Venus is our blazing Evening Star, seen in the west all evening. It will set after midnight. The red planet Mars is in Gemini, left and a bit below Pollux, the leftmost of the namesake stars of the twins, with Castor on the right. Mars is above and left of Venus. By 20 degrees, or two times the width of one’s fist held at arm’s length. Venus is closing the gap between them, but will never quite reach Mars while they are in the evening sky. The closest they will get is three and a half degrees or 7 moon diameters apart, before Venus pulls back toward the Sun faster than Mars will. In the morning, Saturn will be visible and low in the east-southeast by 5 am, rising at 3:37 am. Both Jupiter and Mercury are too close to the direction of the Sun to be seen.
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

Venus and Mars among the setting winter stars at 10 pm tonight, May 10, 2023. Created using Stellarium, LibreOffice Draw and GIMP.

Saturn and the Moon in the morning sky at 5:30 am. Note the Sagittarius’ Teapot asterism on the right. Created using Stellarium.

Waning gibbous Moon animation with selected features labeled. Labels are centered on their feature. Created using Stellarium, LibreOffice, and GIMP.

Telescopic Venus and Saturn (north up) as they would be seen in a small telescope, with the same magnification tonight, the night of May 10/11, 2023. Apparent diameters: Venus 18.45″ and is 62.1% illuminated; Saturn 16.58″, its rings 38.61″. Mars, too small to be represented here, is 5.12″ in diameter. Both Venus and Saturn are getting larger as they approach us. Created using Cartes du Ciel (Sky Charts).
05/09/2023 – Ephemeris – The planet Uranus’ rings
This is Ephemeris for Tuesday, May 9th. Today the Sun will be up for 14 hours and 35 minutes, setting at 8:57, and it will rise tomorrow at 6:20. The Moon, 3 days before last quarter, will rise at 1:56 tomorrow morning.
Today, the planet Uranus is in conjunction with the Sun. I don’t talk about Uranus that much, because it can’t be spotted in the sky with the naked eye. However, the James Webb Space Telescope observed it, and gave our clearest view of the planet since Voyager 2 flew past it in January 1986. Uranus has a system of rings, which were discovered in March 1977. Though not visible, they blocked the light of a star. Astronomers at the time were trying to get a more accurate diameter of the planet by timing the disappearance of a star behind the planet. Extra short dips in brightness before and after the main occultation revealed the existence of the rings. Uranus also has an extreme axial tilt of 98 degrees.
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
05/08/2023 – Ephemeris – How to find Leo the lion in the sky
This is Ephemeris for Monday, May 8th. Today the Sun will be up for 14 hours and 32 minutes, setting at 8:56, and it will rise tomorrow at 6:22. The Moon, 3 days past full, will rise at 12:57 tomorrow morning.
At 10 p.m. the spring constellation of Leo the lion will be high in the south. It can be found by locating the Big Dipper high overhead and imagining that a hole were drilled in the bottom of the bowl to let the water leak out. It would drip on the back of this giant cat. The Lion is standing or lying facing westward. His head and mane are seen in the stars as a backwards question mark. This group of stars is also called the sickle. The bright star Regulus is at the bottom, the dot at the bottom of the question mark. A triangle of stars, to the left of Regulus, is the lion’s haunches. Leo contains some nice galaxies visible in moderate sized telescopes. The stars in Leo’s part of the sky are fewer than those in the winter sky.
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

Finding Leo the lion from the Big Dipper with no lines. The orientation is for 10 pm, May 8th. Can you find Leo? The Big Dipper? Created using Cartes du Ciel (Sky Charts).

Using the Big Dipper to find Leo. The orientation is for 10 pm on May 8th. For any other time, the orientation would be different, as would the position of the zenith (overhead point). Created using my LookingUp app.
Note the star at the left end of Leo is named Denebola. There are several stars that start with “Deneb”. Deneb must mean tail in Arabic because most star names are Arabic in origin. Denebola is the tail of the lion. Deneb Kaitos is the tail of the autumn constellation of Cetus the whale, and Deneb itself is the tail of the summer constellation of Cygnus the swan.
05/05/2023 – Ephemeris – Learn about the upcoming total solar eclipse tonight
This is Ephemeris for Cinco de Mayo, Friday, May 5th. Today the Sun will be up for 14 hours and 25 minutes, setting at 8:52, and it will rise tomorrow at 6:25. The Moon, at full today, will rise at 9:13 this evening.
Eleven months is not too early to plan for a total solar eclipse. On April 8th next year there will be such an eclipse whose path of totality clips the southeastern corner of Michigan. Indianapolis, Toledo and Cleveland also lie in the path of totality. The path runs from Texas to Maine. Member Dan Dall’Olmo will have all the particulars at this month’s meeting of the Grand Traverse Astronomical Society, starting at 8 pm tonight at Northwestern Michigan College’s Joseph H. Rogers Observatory. For those staying home, the Sun for this eclipse will be a bit more covered by the Moon than the 2017 August solar eclipse. We’ll also have another partial solar eclipse to practice on this October 14th.
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
05/04/2023 – Ephemeris – The Moon is not quite as dry as we thought
This is Ephemeris for Thursday, May 4th. Today the Sun will be up for 14 hours and 22 minutes, setting at 8:51, and it will rise tomorrow at 6:27. The Moon, 1 day before full, will set at 6:18 tomorrow morning.
The Moon appears to be bone dry. The Apollo astronauts found no rocks with any water in them, or bound to them chemically. However, remote sensing satellites and an infrared flying observatory have detected hints that water does indeed exist on the Moon. Indeed, water would be worth its weight in gold if discovered there. The South Pole of the Moon has permanently shadowed craters which seem to have water ice in them. Recently the, since decommissioned, SOFIA aircraft, sporting an infrared telescope detected water on the daytime side of the Moon, in quantities, to mix units of measurement, 12 ounces of water per cubic meter of soil in the crater Clavius. It’s a large crater in the Southern Hemisphere of the Moon, and incidentally one of my favorite craters.
Also, recently, the Chinese Chang’e 5 lunar sample return mission detected water in the tiny glass beads that were part of the soil it brought back. The beads were the result of meteorite impacts. Maybe NASA might have another look at the lunar soil the Apollo astronauts brought back.
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
05/03/2023 – Ephemeris – Let’s find where the naked-eye planets have wandered off to this week
This is Ephemeris for Wednesday, May 3rd. Today the Sun will be up for 14 hours and 19 minutes, setting at 8:49, and it will rise tomorrow at 6:28. The Moon, 2 days before full, will set at 5:56 tomorrow morning.
Let’s find where the naked-eye planets have wandered off to this week. Venus is our blazing Evening Star, seen in the west all evening. It will set after midnight. The red planet Mars is in Gemini, below Pollux, left of Castor, the namesake stars of the twins. Mars is above and left of Venus by 24 degrees, or almost two and a half times the width of one’s fist held at arm’s length. Venus is closing the gap between them, but will never quite reach Mars while they are in the evening sky. The closest they will get is three and a half degrees or 7 moon diameters apart, before Venus pulls back toward the Sun faster than Mars will. Saturn, low in the southeast by 6 am, is emerging from morning twilight, rising at 4:07 am. Both Jupiter and Mercury are too close to the direction of the Sun to be seen.
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

Venus and Mars among the setting winter stars tonight, at 10 pm, May 3rd, 2023. Click or tap on the image to enlarge it. Created using Stellarium, Libreoffice Draw and GIMP.

Moon 2 days before full, annotated for 10 pm, May 3, 2023. Created using Stellarium, LibreOffice Draw, and GIMP.

Telescopic Venus and Saturn (north up) as they would be seen in a small telescope, with the same magnification. Apparent diameters: Venus 17.43″ and is 65.2% illuminated; Saturn 16.39″, its rings 38.19″. Mars, too small to be represented here, is 5.30″ in diameter. Created using Cartes du Ciel (Sky Charts).
05/02/2023 – Ephemeris – SpaceX finally launched its Super Heavy/Starship rocket
This is Ephemeris for Tuesday, May 2nd. Today the Sun will be up for 14 hours and 17 minutes, setting at 8:48, and it will rise tomorrow at 6:30. The Moon, 3 days before full, will set at 5:37 tomorrow morning.
On April 20th SpaceX finally launched their Starship atop the Super Heavy, which is the booster for the Starship for an attempted orbital test flight, from Star Base at Boca Chica, Texas. As we all know, it did not reach orbit. It made it about 36 kilometers up or about 22 miles before it lost control and had to be destroyed, however what it did to the launchpad and its surroundings is rather disheartening Elon Musk thought he could get away with not having a flame diverter underneath the launch mount. The Super heavy, which is undoubtedly the most powerful rocket in the world, dug a hole underneath the launch mount and threw big chunks of concrete all over the place damaging their launch infrastructure, and raining debris on a neighboring town. SpaceX will have to make lots of changes before they can launch 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
05/01/2023 – Ephemeris – Previewing May Skies
This is Ephemeris for Monday, the first of May. Today the Sun will be up for 14 hours and 14 minutes, setting at 8:47, and it will rise tomorrow at 6:31. The Moon, halfway from first quarter to full, will set at 5:20 tomorrow morning.
Let’s look ahead at the month of May, the month when the promise of spring is finally fulfilled. Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 14 minutes today 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 60 degrees today to 67 degrees at month’s end. The altitude of the Sun in the Straits area will be a degree lower than that. Local apparent noon this month, when the Sun passes due south, will be about 1:38 p.m. Early this month we’ll have The Eta Aquariid meteor shower early in the morning, though it will be hindered by a bright Moon. Venus and Mars are our evening planets. Venus will continue to approach Mars all month.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –4 hours). They may be different for your location.
Addendum
May Evening Star Chart

Star Chart for May 2023 (11 p.m. EDT, May 15, 2023). Click or tap on image to enlarge it. Created using my LookingUp program.
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

Star Chart for May mornings, 2023 (4 a.m. EDT, May 15, 2023). Click or tap on image to enlarge it. 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.
- 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. |
| 2023-05-01 | 4h41m | 5h26m | 22h02m | 22h46m | – | – | 0.87 |
| 2023-05-02 | 4h39m | 5h24m | 22h03m | 22h48m | – | – | 0.93 |
| 2023-05-03 | 4h37m | 5h22m | 22h05m | 22h50m | – | – | 0.97 |
| 2023-05-04 | 4h35m | 5h20m | 22h06m | 22h52m | – | – | 1.00 |
| 2023-05-05 | 4h33m | 5h19m | 22h08m | 22h54m | – | – | 1.00 |
| 2023-05-06 | 4h31m | 5h17m | 22h10m | 22h56m | – | – | 0.97 |
| 2023-05-07 | 4h29m | 5h15m | 22h11m | 22h58m | 22h58m | 23h48m | 0.93 |
| 2023-05-08 | 4h27m | 5h14m | 22h13m | 23h00m | 23h00m | – | 0.85 |
| 2023-05-09 | 4h24m | 5h12m | 22h14m | 23h02m | 23h02m | 0h58m | 0.76 |
| 2023-05-10 | 4h22m | 5h10m | 22h16m | 23h04m | 23h04m | 1h56m | 0.66 |
| 2023-05-11 | 4h20m | 5h09m | 22h17m | 23h06m | 23h06m | 2h42m | 0.55 |
| 2023-05-12 | 4h18m | 5h07m | 22h19m | 23h08m | 23h08m | 3h17m | 0.43 |
| 2023-05-13 | 4h16m | 5h06m | 22h20m | 23h10m | 23h10m | 3h45m | 0.32 |
| 2023-05-14 | 4h14m | 5h04m | 22h22m | 23h12m | 23h12m | 4h08m | 0.22 |
| 2023-05-15 | 4h12m | 5h03m | 22h23m | 23h14m | 23h14m | 4h12m | 0.14 |
| 2023-05-16 | 4h10m | 5h01m | 22h25m | 23h16m | 23h16m | 4h10m | 0.07 |
| 2023-05-17 | 4h09m | 5h00m | 22h26m | 23h18m | 23h18m | 4h09m | 0.02 |
| 2023-05-18 | 4h07m | 4h58m | 22h28m | 23h20m | 23h20m | 4h07m | 0.00 |
| 2023-05-19 | 4h05m | 4h57m | 22h29m | 23h22m | 23h22m | 4h05m | 0.00 |
| 2023-05-20 | 4h03m | 4h56m | 22h31m | 23h23m | 23h23m | 4h03m | 0.03 |
| 2023-05-21 | 4h01m | 4h54m | 22h32m | 23h25m | 23h51m | 4h01m | 0.07 |
| 2023-05-22 | 3h59m | 4h53m | 22h34m | 23h27m | – | 3h59m | 0.12 |
| 2023-05-23 | 3h58m | 4h52m | 22h35m | 23h29m | 0h43m | 3h58m | 0.20 |
| 2023-05-24 | 3h56m | 4h51m | 22h36m | 23h31m | 1h26m | 3h56m | 0.28 |
| 2023-05-25 | 3h54m | 4h49m | 22h38m | 23h33m | 1h59m | 3h54m | 0.37 |
| 2023-05-26 | 3h53m | 4h48m | 22h39m | 23h35m | 2h26m | 3h53m | 0.46 |
| 2023-05-27 | 3h51m | 4h47m | 22h40m | 23h37m | 2h48m | 3h51m | 0.55 |
| 2023-05-28 | 3h49m | 4h46m | 22h42m | 23h38m | 3h07m | 3h49m | 0.65 |
| 2023-05-29 | 3h48m | 4h45m | 22h43m | 23h40m | 3h25m | 3h48m | 0.74 |
| 2023-05-30 | 3h47m | 4h44m | 22h44m | 23h42m | 3h42m | 3h47m | 0.82 |
| 2023-05-31 | 3h45m | 4h43m | 22h45m | 23h44m | – | – | 0.90 |
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
LU Ephemeris of Sky Events for Interlochen/TC May 2023 Local time zone: EDT +-----------------------------------------------------------------------+ | DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM | | | RISE SET HOURS | END START |PHASE SET** TIME FRACTN| +=======================================================================+ |Mon 1| 06:33a 08:47p 14:14 | 09:59p 05:21a | Set 05:20a 86%| |Tue 2| 06:31a 08:48p 14:17 | 10:01p 05:19a | Set 05:37a 92%| |Wed 3| 06:30a 08:49p 14:19 | 10:02p 05:17a | Set 05:56a 97%| |Thu 4| 06:28a 08:51p 14:22 | 10:04p 05:15a | Set 06:18a 99%| |Fri 5| 06:27a 08:52p 14:25 | 10:06p 05:14a |Full Rise 09:13p 100%| |Sat 6| 06:25a 08:53p 14:27 | 10:07p 05:12a | Rise 10:31p 98%| +------+-----------------------+----------------+-----------------------+ |Sun 7| 06:24a 08:54p 14:30 | 10:09p 05:10a | Rise 11:47p 94%| |Mon 8| 06:23a 08:56p 14:32 | 10:10p 05:08a | Rise 12:57a 87%| |Tue 9| 06:22a 08:57p 14:35 | 10:12p 05:07a | Rise 01:56a 78%| |Wed 10| 06:20a 08:58p 14:37 | 10:13p 05:05a | Rise 02:42a 68%| |Thu 11| 06:19a 08:59p 14:40 | 10:15p 05:04a | Rise 03:17a 57%| |Fri 12| 06:18a 09:00p 14:42 | 10:16p 05:02a |L Qtr Rise 03:44a 45%| |Sat 13| 06:17a 09:01p 14:44 | 10:18p 05:00a | Rise 04:07a 34%| +------+-----------------------+----------------+-----------------------+ |Sun 14| 06:15a 09:03p 14:47 | 10:19p 04:59a | Rise 04:28a 24%| |Mon 15| 06:14a 09:04p 14:49 | 10:21p 04:57a | Rise 04:47a 15%| |Tue 16| 06:13a 09:05p 14:51 | 10:23p 04:56a | Rise 05:08a 8%| |Wed 17| 06:12a 09:06p 14:53 | 10:24p 04:54a | Rise 05:30a 3%| |Thu 18| 06:11a 09:07p 14:55 | 10:25p 04:53a | Rise 05:56a 1%| |Fri 19| 06:10a 09:08p 14:58 | 10:27p 04:52a |New Set 09:38p 0%| |Sat 20| 06:09a 09:09p 15:00 | 10:28p 04:50a | Set 10:48p 2%| +------+-----------------------+----------------+-----------------------+ |Sun 21| 06:08a 09:10p 15:02 | 10:30p 04:49a | Set 11:50p 6%| |Mon 22| 06:07a 09:11p 15:04 | 10:31p 04:48a | Set 12:43a 11%| |Tue 23| 06:06a 09:12p 15:05 | 10:33p 04:46a | Set 01:25a 18%| |Wed 24| 06:06a 09:13p 15:07 | 10:34p 04:45a | Set 01:59a 26%| |Thu 25| 06:05a 09:14p 15:09 | 10:35p 04:44a | Set 02:26a 35%| |Fri 26| 06:04a 09:15p 15:11 | 10:37p 04:43a | Set 02:48a 44%| |Sat 27| 06:03a 09:16p 15:13 | 10:38p 04:42a |F Qtr Set 03:07a 53%| +------+-----------------------+----------------+-----------------------+ |Sun 28| 06:02a 09:17p 15:14 | 10:39p 04:41a | Set 03:24a 63%| |Mon 29| 06:02a 09:18p 15:16 | 10:40p 04:40a | Set 03:41a 72%| |Tue 30| 06:01a 09:19p 15:17 | 10:42p 04:39a | Set 03:59a 81%| |Wed 31| 06:01a 09:20p 15:19 | 10:43p 04:38a | Set 04:19a 88%| +-----------------------------------------------------------------------+ * Nautical Twilight ** Moonrise or moonset, whichever occurs between sunset and the next sunrise












