06/02/2023 – Ephemeris – A South Pole adventure and a comet collision presentation – Tonight!

June 2, 2023 Leave a comment

This is Bob Moler with Ephemeris for Friday, June 2nd. Today the Sun will be up for 15 hours and 22 minutes, setting at 9:22, and it will rise tomorrow at 5:59. The Moon, 1 day before full, will set at 5:14 tomorrow morning.

An Antarctic Odyssey: Winter-Over at South Pole Station will be the presentation by John W. Briggs, via Zoom, at tonight’s meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers Observatory at 9 pm. John was a team member building a 24-inch infrared telescope and related experiments that were set up at the South Pole in time for him and colleagues to observe the July 1994, explosive crash of fragmented comet Shoemaker-Levy 9 into the planet Jupiter. There are two ways to attend: In person at the observatory, south of Traverse City on Birmley Road, or via Zoom with a link provided by the society’s website gtastro.org just prior to the meeting.

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

Images of Jupiter in the infrared before and after Fragment C of Comet Shoemaker-Levy 9 struck Jupiter. The brightness reveals temperature of the atmosphere. Credit: University of Chicago.

About the Program

An Antarctic Odyssey: Winter-Over at South Pole Station

A presentation via Zoom by John W. Briggs

Abstract:
In a lavishly illustrated presentation, John W. Briggs of New Mexico will describe his year-long experience living at the Geographic South Pole while working for the Center for Astrophysical Research in Antarctica. In preparation for this at Yerkes Observatory of the University of Chicago, John was a team member building a 24-inch infrared telescope and related experiments that were set up at the Pole in time for him and colleagues to observe the July 1994, explosive crash of fragmented comet Shoemaker-Levy 9 into the planet Jupiter.

John weathered the “winter-over” with 26 other members of the U.S. Antarctic Program in an experience that many believe approximates what life will be like someday at a lunar or Martian outpost. Once begun, South Pole winter-over is an irreversible commitment, since the Program’s special LC-130 ski planes can’t land in the winter temperatures — in 1994, sometimes as low as 107 degrees F. below zero (with windchill, as low as -180 degrees). John will delight the audience with his perspective on the total South Pole experience — the strange natural environment, the odd social atmosphere, and the challenging, ongoing science.

06/01/2023 – Ephemeris – Previewing June Skies

June 1, 2023 Leave a comment

This is Bob Moler with Ephemeris for Thursday, June 1st. Today the Sun will be up for 15 hours and 20 minutes, setting at 9:21, and it will rise tomorrow at 5:59. The Moon, 2 days before full, will set at 4:43 tomorrow morning.

Let’s begin this program’s 49th trip around the Sun by previewing the skies of June. There will be a lot of Sun in June and very little night. The daylight hours will increase a bit from 15 hours and 20 minutes today to 15 hours and 34 minutes on the 21st, retreating back to 15 hours 31 minutes at month’s end. At this time of the year the sunset times for Ludington, Interlochen, Petoskey and Mackinaw City are very nearly the same. However, the sunrise times are at their most divergent. With Ludington’s sunrise being 14 minutes later than Mackinaw City’s. The altitude of the Sun above the southern horizon at local noon around 1:43 p.m. will hover around 68 to 69 degrees. Summer will start on the 21st at 10:58 a.m. Venus will look great in our skies and in telescopes this month.

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

June Evening Star Chart

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

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 Interlochen/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.

June Morning Star Chart

Star Chart for June mornings, 2023 (4 am EDT, June 15, 2023). Created using my LookingUp program. Click or tap on the image to enlarge it.

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,

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning Twilight Evening Twilight Dark Night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2023-06-01 3h44m 4h43m 22h46m 23h45m 0.95
2023-06-02 3h43m 4h42m 22h48m 23h47m 0.99
2023-06-03 3h41m 4h41m 22h49m 23h48m 1.00
2023-06-04 3h40m 4h40m 22h50m 23h50m 0.98
2023-06-05 3h39m 4h40m 22h51m 23h51m 0.94
2023-06-06 3h38m 4h39m 22h52m 23h53m 23h53m 0.87
2023-06-07 3h37m 4h38m 22h53m 23h54m 23h54m 0h39m 0.79
2023-06-08 3h36m 4h38m 22h53m 23h55m 23h55m 1h18m 0.68
2023-06-09 3h35m 4h38m 22h54m 23h56m 23h56m 1h49m 0.57
2023-06-10 3h35m 4h37m 22h55m 23h58m 23h58m 2h13m 0.46
2023-06-11 3h34m 4h37m 22h56m 23h59m 23h59m 2h34m 0.35
2023-06-12 3h33m 4h36m 22h57m 0h00m 0h00m 2h54m 0.25
2023-06-13 3h33m 4h36m 22h57m 0h01m 0h01m 3h13m 0.16
2023-06-14 3h32m 4h36m 22h58m 0h01m 0h01m 3h32m 0.09
2023-06-15 3h32m 4h36m 22h58m 0h02m 0h02m 3h32m 0.04
2023-06-16 3h32m 4h36m 22h59m 0h03m 0h03m 3h32m 0.01
2023-06-17 3h32m 4h36m 22h59m 0h04m 0h04m 3h32m 0.00
2023-06-18 3h32m 4h36m 23h00m 0h04m 0h04m 3h32m 0.01
2023-06-19 3h32m 4h36m 23h00m 0h04m 0h04m 3h32m 0.04
2023-06-20 3h32m 4h36m 23h00m 0h05m 0h05m 3h32m 0.08
2023-06-21 3h32m 4h36m 23h01m 0h05m 0h05m 3h32m 0.15
2023-06-22 3h32m 4h37m 23h01m 0h05m 0h28m 3h32m 0.22
2023-06-23 3h32m 4h37m 23h01m 0h05m 0h51m 3h32m 0.30
2023-06-24 3h33m 4h37m 23h01m 0h05m 1h11m 3h33m 0.39
2023-06-25 3h33m 4h38m 23h01m 0h05m 1h29m 3h33m 0.49
2023-06-26 3h34m 4h38m 23h01m 0h05m 1h46m 3h34m 0.59
2023-06-27 3h35m 4h39m 23h01m 0h05m 2h03m 3h35m 0.68
2023-06-28 3h35m 4h39m 23h01m 0h04m 2h22m 3h35m 0.78
2023-06-29 3h36m 4h40m 23h01m 0h04m 2h43m 3h36m 0.86
2023-06-30 3h37m 4h40m 23h00m 0h03m 3h10m 3h37m 0.93

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

  Date       Time     Event
Jun  1  Th            Venus: 45.4° E
     1  Th   2:22 am  Moon Descending Node
     1  Th  11:30 pm  Mars-Beehive:  0.1° S
     3  Sa   5:19 pm  Moon-Antares: 1.6° S
     3  Sa  11:42 pm  Full Strawberry Moon
     4  Su   6:59 am  Venus Elongation: 45.4° E
     5  Mo  12:21 pm  Moon South Dec.: 27.9° S
     6  Tu   7:07 pm  Moon Perigee: 364,900 km
     9  Fr   4:19 pm  Moon-Saturn: 3° N
    10  Sa   3:31 pm  Last Quarter
    11  Su   1:50 pm  Mercury-Pleiades: 6.2° S
    13  Tu   7:05 am  Venus-Beehive:  0.5° N
    13  Tu   8:05 pm  Moon Ascending Node
    14  We   2:33 am  Moon-Jupiter: 1.6° S
    15  Th   8:47 pm  Moon-Pleiades: 2° N
    16  Fr   4:18 pm  Mercury-Aldebaran: 4.3° N
    18  Su  12:37 am  New Moon
    18  Su   5:07 pm  Moon North Dec.: 27.8° N
    20  Tu   5:10 am  Moon-Pollux: 1.9° N
    21  We   6:38 am  Moon-Beehive: 4° S
    21  We  10:58 am  Summer Solstice
    21  We   8:47 pm  Moon-Venus: 4.1° S
    22  Th   6:09 am  Moon-Mars: 4.2° S
    22  Th   2:31 pm  Moon Apogee: 405,400 km
    26  Mo   3:50 am  First Quarter
    28  We   8:22 am  Moon Descending Node
Jul  1  Sa            Venus: 41.7° 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
June, 2023    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Thu  1| 06:00a  09:21p  15:20 | 10:44p  04:37a |      Set  04:43a   94%|
|Fri  2| 05:59a  09:22p  15:22 | 10:45p  04:36a |      Set  05:14a   98%|
|Sat  3| 05:59a  09:22p  15:23 | 10:46p  04:35a |Full  Rise 09:27p  100%|
+------+-----------------------+----------------+-----------------------+
|Sun  4| 05:59a  09:23p  15:24 | 10:47p  04:35a |      Rise 10:42p   99%|
|Mon  5| 05:58a  09:24p  15:25 | 10:48p  04:34a |      Rise 11:47p   95%|
|Tue  6| 05:58a  09:25p  15:26 | 10:49p  04:33a |      Rise 12:39a   89%|
|Wed  7| 05:57a  09:25p  15:27 | 10:50p  04:33a |      Rise 01:18a   80%|
|Thu  8| 05:57a  09:26p  15:28 | 10:51p  04:32a |      Rise 01:48a   70%|
|Fri  9| 05:57a  09:27p  15:29 | 10:52p  04:32a |      Rise 02:13a   59%|
|Sat 10| 05:57a  09:27p  15:30 | 10:53p  04:31a |L Qtr Rise 02:34a   48%|
+------+-----------------------+----------------+-----------------------+
|Sun 11| 05:56a  09:28p  15:31 | 10:53p  04:31a |      Rise 02:53a   37%|
|Mon 12| 05:56a  09:28p  15:31 | 10:54p  04:31a |      Rise 03:13a   27%|
|Tue 13| 05:56a  09:29p  15:32 | 10:55p  04:30a |      Rise 03:34a   18%|
|Wed 14| 05:56a  09:29p  15:33 | 10:55p  04:30a |      Rise 03:59a   10%|
|Thu 15| 05:56a  09:30p  15:33 | 10:56p  04:30a |      Rise 04:28a    5%|
|Fri 16| 05:56a  09:30p  15:33 | 10:56p  04:30a |      Rise 05:04a    2%|
|Sat 17| 05:56a  09:30p  15:34 | 10:57p  04:30a |      Rise 05:49a    0%|
+------+-----------------------+----------------+-----------------------+
|Sun 18| 05:56a  09:31p  15:34 | 10:57p  04:30a |New   Set  10:36p    1%|
|Mon 19| 05:56a  09:31p  15:34 | 10:57p  04:30a |      Set  11:22p    3%|
|Tue 20| 05:56a  09:31p  15:34 | 10:58p  04:30a |      Set  11:58p    8%|
|Wed 21| 05:57a  09:32p  15:34 | 10:58p  04:30a |      Set  12:27a   13%|
|Thu 22| 05:57a  09:32p  15:34 | 10:58p  04:31a |      Set  12:51a   20%|
|Fri 23| 05:57a  09:32p  15:34 | 10:58p  04:31a |      Set  01:11a   28%|
|Sat 24| 05:57a  09:32p  15:34 | 10:58p  04:31a |      Set  01:29a   37%|
+------+-----------------------+----------------+-----------------------+
|Sun 25| 05:58a  09:32p  15:34 | 10:58p  04:32a |      Set  01:45a   47%|
|Mon 26| 05:58a  09:32p  15:33 | 10:58p  04:32a |F Qtr Set  02:02a   57%|
|Tue 27| 05:59a  09:32p  15:33 | 10:58p  04:33a |      Set  02:21a   66%|
|Wed 28| 05:59a  09:32p  15:32 | 10:58p  04:33a |      Set  02:43a   76%|
|Thu 29| 05:59a  09:32p  15:32 | 10:58p  04:34a |      Set  03:10a   84%|
|Fri 30| 06:00a  09:32p  15:31 | 10:57p  04:34a |      Set  03:45a   92%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

05/31/2023 – Ephemeris – Let’s find where the naked-eye planets have wandered off to this week

May 31, 2023 Leave a comment

This is Bob Moler with Ephemeris for Wednesday, May 31st. Today the Sun will be up for 15 hours and 19 minutes, setting at 9:20 pm, and it will rise tomorrow at 6 am. The Moon, 3 days before full, will set at 4:19 am tomorrow.

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 has moved into Cancer, and is seen above and left of Venus by 12 degrees, or a bit more than 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 low in the southeast at 5 am, rising at 2:28 am. Jupiter makes its morning appearance and is low in the east-northeast at that hour, rising at 4:27 am.

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 with the stars Castor and Pollux in Gemini at 10:30 pm tonight, May 31, 2023. By tomorrow night, Venus will pull up to be in line with Castor and Pollux. Created using Stellarium.
The Moon as it might appear tonight t 10:30 pm, May 31, 2023, through binoculars or a small telescope. Created using Stellarium, LibreOffice Draw and GIMP.
Jupiter and Saturn at 5 am tomorrow morning, June 1, 2023. Click or tap on the image to enlarge it. Created using Stellarium.
Telescopic Venus, Saturn and Jupiter (north up) as they would be seen in a small telescope, with the same magnification at 10:30 pm for Venus and 5 am for Jupiter and Saturn. Apparent diameters: Venus 22.65″ and is 51.7% illuminated; Saturn 17.17″, its rings 39.99″; Jupiter 34.43″. Mars, too small to be represented here, is 4.68″ in diameter. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on May 31, 2023. The night ends on the left with sunrise on the June 1st. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.

05/30/2023 – Ephemeris – The Terminator… No, not Arnold Swartzenegger

May 30, 2023 Leave a comment

This is Ephemeris for Tuesday, May 30th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:19, and it will rise tomorrow at 6:01. The Moon, 3 days past first quarter, will set at 3:59 tomorrow morning.

The Moon tonight is getting to be a fatter and fatter gibbous phase, until Saturday, when it will be full. The Moon will be blindingly bright in telescopes of low magnification. As always the case with the Moon, the most detail is seen near the terminator. The terminator, in the case of the waxing moon, is the sunrise line. After full moon, the terminator becomes the sunset line. This is where the shadows are longest, showing the detail of the craters. Farther from the terminator, where the Sun is higher in the Moon’s sky, shadows are short or nonexistent. Giving the surface a flat appearance. Even lacking wind and water, there is still erosion on the Moon, coming from meteoroid and asteroid impacts and their ejecta. And the breakdown of rocks due to the extreme day-night temperature swings.

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

Moon First Quarter plus 3 days
The first quarter plus 3 day old Moon tonight at around 10 pm with labels of selected features. Gassendi is a great crater to check out with a telescope. It is only really visible when near the terminator. A hint: Mare (pronounced Mar-e) means sea. Created using Stellarium, LibreOffice Draw, and GIMP.

05/29/2023 – Ephemeris – Sinus Iridium, a hook into night

May 29, 2023 Comments off

This is Bob Moler with Ephemeris for Memorial Day, Monday, May 29th. Today the Sun will be up for 15 hours and 16 minutes, setting at 9:18, and it will rise tomorrow at 6:01. The Moon, 2 days past first quarter, will set at 3:41 tomorrow morning.

Let’s look at the Moon tonight. One of my favorite formations is coming into light. It is called Sinus Iridium or Bay of Rainbows. Sorry, there’s no color here. But if caught at right time, and tonight’s the night, this ruined crater will appear as a hook out into night off the upper left edge of the moon. Officially it’s a bay to the Sea of Showers or Mare Imbrium. The north edge of the bay are mountains called the Jura Mountains. The south edge disappears into Mare Imbrium. The floor of the Sinus Iridium is about twelve hundred feet lower than Mare Imbrium. The transition is gradual because it isn’t very noticeable. The formation is large enough to be seen in binoculars. Sinus Iridium is 242 miles wide, a good tenth the diameter of the Moon itself.

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

The northern (upper) part of the Moon tonight, May 29, 2023, at 10 pm. showing the Jura Mountains jutting into darkness at the morning terminator (sunrise line). Click or tap the image to enlarge it. Created using Virtual Moon Atlas, LibreOffice Draw and GIMP.

05/26/2023 – Ephemeris – Sun & Star Party tomorrow at the Sleeping Bear Dunes National Lakeshore

May 26, 2023 Comments off

This is Bob Moler with Ephemeris for Friday, May 26th. Today the Sun will be up for 15 hours and 11 minutes, setting at 9:15, and it will rise tomorrow at 6:03. The Moon, 1 day before first quarter, will set at 2:48 tomorrow morning.

Tomorrow, the Sleeping Bear Dunes National Lakeshore and the Grand Traverse Astronomical Society will host a Sun and Star Party at the Dune Climb area of the park. There will be a solar viewing period from 5 pm to about 7 pm. The society has two hydrogen alpha solar telescopes to view the Sun’s chromosphere and prominences. Plus, some members also have solar scopes and white light filtered telescopes to view sunspots on the face of the Sun. Night viewing will start at 9 pm, with the Moon and Venus featured, along with the brighter telescopic wonders of late spring. There will be a pass of the International Space Station from 10:11 to 10:18 pm. The rangers will have an alternate program if it’s cloudy.

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

DSC02269Dune Climb Sun Party

A Sun Party at the Dune Climb. Credit: Eileen Carlisle.


Preparing to start the star party

Preparing to start the May star party, several years ago at the Dune Climb. A few of the telescopes are visible, including the GTAS 25″ “Emmettron” telescope at the far right background. Credit: Eileen Carlisle.

 

05/25/2023 – Ephemeris – NASA awards contracts for a second lunar lander

May 25, 2023 Comments off

This is Ephemeris for Thursday, May 25th. Today the Sun will be up for 15 hours and 9 minutes, setting at 9:14, and it will rise tomorrow at 6:04. The Moon, 2 days before first quarter, will set at 2:26 tomorrow morning.

A week ago, NASA announced that the contract for the second Artemis moon lander would go to a group of companies headed by Blue Origin for 3.4 billion dollars. Unlike Apollo, the rocket that sens crews to the Moon will not contain a moon landing craft. It will be sent out separately before the crew. SpaceX’s Lunar Starship will be used on the first two landings, for Artemis III and IV, while the Blue Origin lander will be used for Artemis V, sometime around 2029 or later. Little detail has been released about the lander, except for an artist’s rendering. It appears to be shorter than the Boeing lander first proposed, which would require an astronaut to climb up and down a very long ladder. SpaceX’s Starship would be taller still, but will have an elevator on the side.

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

NASA picks Bezos' Blue Origin to build second lunar lander

NASA picks Bezos’ Blue Origin to build second lunar lander. The crew compartment is on the bottom, allowing for a shorter ladder to the surface. The liquid oxygen (LOX) and hydrogen (LH) tanks are on top. The LH tank is on top with sun shields, with the LOX tank below. I’m guessing here, since very little information has been released. Credit: NASA.

The craft is officially known as the Human Landing System (HLS).

05/24/2023 – Ephemeris – Let’s find where the naked-eye planets have wandered off to this week

May 24, 2023 Comments off

This is Ephemeris for Wednesday, May 24th. Today the Sun will be up for 15 hours and 7 minutes, setting at 9:13, and it will rise tomorrow at 6:05. The Moon, 3 days before first quarter, will set at 1:59 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 will appear below the Moon tonight. It has moved into Cancer, and is seen above and left of Venus by 14 degrees, or one 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. In the morning, Saturn will be visible and low in the southeast at 5 am, rising at 2:47 am. Jupiter makes its morning appearance and is very low in the east-northeast 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

Evening planets and the Moon

Evening planets and the Moon at 10 pm tonight, May 24, 2023. Created using Stellarium, LibreOffice Draw and GIMP.

5 day old moon annotated

5 day old Moon with selected features labeled for May 24, 2023, at 10 pm. Created using Stellarium, LibreOffice and GIMP.

Morning planets

Saturn and Jupiter in early morning twilight at 5:00 am tomorrow, May 25, 2023. Created using Stellarium.

Telescopic views of Venus, Saturn and Jupiter

Telescopic Venus, Saturn and Jupiter (north up) as they would be seen in a small telescope, with the same magnification. Apparent diameters: Venus 21.03″ and is 55.4% illuminated; Saturn 16.96″, its rings 39.52″; Jupiter 34.07″. Mars, too small to be represented here, is 4.81″ in diameter. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on May 24, 2023. The night ends on the left with sunrise on the 25th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.

05/23/2023 – Ephemeris – Let’s observe the four-day-old Moon

May 23, 2023 Comments off

This is Bob Moler with Ephemeris for Tuesday, May 23rd. Today the Sun will be up for 15 hours and 5 minutes, setting at 9:12, and it will rise tomorrow at 6:06. The Moon, halfway from new to first quarter, will set at 1:25 tomorrow morning.

The four-day-old Moon has uncovered a sea below Mare Crisium or Sea of Crises. It’s Mare Fecunditatis, or the Sea of Fertility. It appears to have been created in the first period of the Moon’s history from 4.55 billion years to 3.92 billion years ago, called the pre- Nectarian geological period, while Mare Crisium is a bit younger, from 3.92 to 3.85 billion years ago, the Nectarian period. Both periods were named for Mare Nectaris, or Sea of Nectar, a small sea next to the Sea of Fertility just coming into sunlight. There are two small, but remarkable craters in the Sea of Fertility called Messier and Messier A which appear to be the result of a double asteroid impact, where it looks like the Moon was struck at a low angle, sending debris out in one direction.

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

4 day old Moon annotated

4 day old Moon with selected features labeled for May 23, 2023, at 10 pm. Created using Stellarium, LibreOffice Draw and GIMP.

Messier craters finder

Mare Fecunditatis, 4 day old Moon with the 2 Messier craters labeled. Created using Stellarium, LibreOffice Draw and GIMP.

Messier craters from the Apollo astronauts

Messier craters from the Apollo astronauts. Credit NASA.

05/22/2023 – Ephemeris – Exploring the three-day-old Moon

May 22, 2023 Comments off

This is Ephemeris for Monday, May 22nd. Today the Sun will be up for 15 hours and 4 minutes, setting at 9:11, and it will rise tomorrow at 6:06. The Moon, 3 days past new, will set at 12:43 tomorrow morning.

Tonight we will see the three-day-old moon low in the west. It may exhibit earthshine. That is, its night side will be illuminated by the Earth’s day side. Just as the earthly night is illuminated by moonlight, especially when the Moon is near full, the night side of the Moon, when near new, is illuminated by earthlight. In binoculars or telescope, the large dark spot, on the Moon’s right edge, is Mare Crisium, or Sea of Crises. The large crater below and a bit left of that sea is Langrenus, named after a 17th century Belgian engineer and mathematician who produced the first lunar map with nomenclature. Langrenus appears as a bright spot as the Sun rises higher for it. Also check out the south end of the cusp of the crescent for a lone mountain peak catching the Sun.

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

Three day old moon, annotated

An annotated three old Moon as it might appear in binoculars or a small telescope tonight, May 22, 2023, at 10 pm. Click or tap on the image to enlarge it. Created using Stellarium, LibreOffice Draw and GIMP.