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Ephemeris: 05/08/2026 – The story of Boötes and Ursa Major

May 8, 2026 Comments off

This is Ephemeris for Friday, May 8th. Today the Sun will be up for 14 hours and 33 minutes, setting at 8:56, and it will rise tomorrow at 6:21. The Moon, 1 day before last quarter, will rise at 2:55 tomorrow morning.

Appearing in the eastern sky at 10 p.m. tonight is the kite shaped constellation of Boötes the herdsman. The bright star Arcturus is at the bottom of the kite which is horizontal to the left, pointed to by the arc of the handle of the Big Dipper, higher in the east. The Big Dipper is the hind end of the constellation Ursa Major, the Great Bear. In one story, Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young woman who had the misfortune of being loved by god Zeus. Zeus’ wife, Hera, found out about the affair, and since she couldn’t punish Zeus, turned the poor woman into a bear. Arcas, many years later, unaware of why his mother disappeared, was about to kill the bear when Zeus intervened and placed them both in the sky, where he continues to chase her across the sky nightly.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

A GIF finder image for the constellations Boötes, Ursa Major, and Canes Venatici. It shows, in three frames: the sky as it would appear high in the east, the same image with constellation lines, and the art from the Stellariam app. See the caption for the image below for the inclusion of Canis Venatici.
A Google Gemini AI image created from a prompt I made which encapsulated the encounter of Arcas and the bear.
This is a Google Gemini AI image created from a prompt I made which encapsulated the encounter of Arcas and the bear in very sketchy terms. The source that it referenced turned out to be my April 26, 2019 Ephemeris post which is virtually identical to the one today. It was illustrated with a 17th century woodcut, which looked nothing like this image. I was kinda hoping it would have found another source, somewhere. I can’t be the only one. This is the second mythological image I requested from Gemini, and in both cases it created an image in the style of a renaissance painter. I noticed too that the bear has a look of recognition on its face. Gemini also included hunting dogs. Of course, Arcas would have had hunting dogs, and there is a constellation of the hunting dogs nearby. It’s just two stars, called Canes Venatici. I’ve ignored its part of the story all these years, so starting now I’m adding it in.
Categories: Constellations, Ephemeris Program, Mythology, Observing Tags: , , , , ,

Ephemeris: 05/07/2026 – A constellation of a real person: Coma Berenices

May 7, 2026 Comments off

This is Ephemeris for Thursday, May 7th. Today the Sun will be up for 14 hours and 30 minutes, setting at 8:55, and it will rise tomorrow at 6:22. The Moon, 2 days before last quarter, will rise at 2:28 tomorrow morning.

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. Berenice was a real queen, whose husband, the Pharaoh Ptolemy III, was away at war. Those were the days when the Greeks ruled Egypt. 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. Later, the constellation of Coma Berenices has been made to commemorate the queen’s sacrifice.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

A Coma Berenices finder. The Babylonians, who predated Queen Berenice, saw the cluster of stars as the tuft at the end of Leo the lion’s tail. The constellation, as we know it now was given by Tycho Brahe, the prominent 16th century observational astronomer. Created using Stellarium and LibreOffice Draw.
Coma Berenices cluster binocular view.
Approximate 7 power binocular field of view (FOV) of the Coma Berenices Cluster. Created using Cartes du Ciel (Sky Charts).

Categories: Constellations, Ephemeris Program, Mythology, Observing Tags:

Ephemeris: 05/06/2026 – Taking our weekly look at the whereabouts of the naked-eye planets

May 6, 2026 Comments off

This is Ephemeris for Wednesday, May 6th. Today the Sun will be up for 14 hours and 28 minutes, setting at 8:53, and it will rise tomorrow at 6:24. The Moon, 3 days before last quarter, will rise at 1:55 tomorrow morning.

Let’s take our weekly look at the whereabouts of the naked-eye planets. By 9:30 PM tonight or about 35 minutes or so after sunset, Venus may be seen very low in the West. A telescope will show a very tiny disc on Venus, because it is still pretty much beyond the Sun, 131 million miles (211 million kilometers) away from us. Over the next 5½ months it will be moving closer to us and becoming much larger. Jupiter is the brilliant star-like object in the western before 10 PM. It is above and left of the brighter Venus. Venus will set at 11:26 PM, while Jupiter will hold out until 1:40 AM. Saturn may be glimpsed starting about next Monday just after it rises in the east around 5:15 AM, and before morning twilight overwhelms it sometime later.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

Jupiter, and Venus with fading winter stars at 10 PM tonight, May 6, 2026.
Jupiter, and Venus with fading winter stars at 10 PM tonight, May 6, 2026. Jupiter and Venus are appearing to approach each other. They will be in conjunction on the evening of June 8th. Created using Stellarium.
The Moon, 2 days before last quarter, as seen at 5 AM tomorrow morning, May 7, 2026. A view visible in small telescopes showing an image with and without selected features labeled. Created using Stellarium, LibreOffice Draw, and GIMP.
Telescopic Jupiter and Venus (north up) as they would be seen in a small telescope with the same magnification.
Telescopic Jupiter and Venus (north up) as they would be seen in a small telescope with the same magnification. Venus will be visible for a short time near the western horizon, while Jupiter will be visible until after midnight. Venus’ apparent diameter will be 11.9″, and be 86.5% illuminated. It’s on the far side of the Sun. Jupiter will be 35.0″ in diameter, with its moons shown here for 10 PM, tonight May 6, 2026. Callisto will begin to transit the face of Jupiter at 10:31 PM.. Europa will pass behind the planet (an occultation) beginning at 11:36 PM. The moons can shift noticably over an hour, especially Io and Europa. The (”) symbol means seconds of arc, or 1/3600th of a degree. Created using Cartes du Ciel (Sky Charts), LibreOffice Draw and GIMP.
The naked-eye planets at sunset and sunrise on a single night.
The naked-eye planets at sunset and sunrise on a single night, starting with sunset on the right on May 6, 2026. The night ends on the left with sunrise on the 7th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
A low precision ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, May 6 and 7th, 2026.
This is a low precision ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, May 6 and 7th, 2026. Some of the columns are self-explanatory, others are not. The transit column is the time that the body crosses the meridian and is due south. Elong, for elongation, is the angle between the Sun and that body. RA is right ascension, which is the object’s east-west position on the celestial sphere in hours and minutes. Dec is declination which is the north-south position of the object on the celestial sphere in degrees and minutes. R is the distance of that object from the Sun in astronomical units. An astronomical unit is about 93 million miles or 150 million kilometers. And Delta is the distance of that object from the Earth, also in astronomical units. I omit the ‘m’ in am and pm for compactness. The data was generated using my LookingUp for DOS app and displayed as a table by my Ephemeris Helper app.

Categories: Ephemeris Program, Naked-eye planets, Observing Tags: , , , , ,

Ephemeris: 05/05/2026 – The constellation of Hydra the water snake slithers along the southern horizon

May 5, 2026 Comments off

This is Bob Moler with Ephemeris for Cinco de Mayo, Tuesday, 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, halfway from full to last quarter, will rise at 1:15 tomorrow morning.

Low in the southwest to the southeastern sky in the evening one can spot 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 actually its most distinctive part. At 10 p.m. the head of Hydra is found below a line from brilliant Jupiter in the west and 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 and Corvus the crow. Some delineations of Hydra have its tail tickling the constellation Libra, the balance, or scales, which has just risen in the southeast.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

How to find the hydra the water snake 2026 edition. The head of Hydra the water snake can be found this spring by imagining a line between Jupiter and Leo the lion, specifically the bright star Regulus. Dropping below about the center of that line and find Hydra’s distinctive head. From there follow the stars down to the lower left towards the horizon, under Corvus and the crow, and the star Spica. I’ll talk about Corvus later this week. The snake’s tail ends near the horizon in the southeast near the constellation of Libra the scales. Also off the lower right-hand side of the image is the brilliant planet Venus, so don’t confuse that with Jupiter. Created using Stellarium, LibreOffice Draw, and GIMP.

The head of Hydra and the front part of Leo are parts of a constellation of the original inhabitants of our area, the Anishinaabek peoples. The constellation is the Great Underwater Panther, and the front part of the Leo is its curly tail. For more information about it check my blog post here.

Categories: Constellations, Ephemeris Program, Observing Tags:

Ephemeris: 05/04/2026 – Looking out of the Milky Way

May 4, 2026 Comments off

This is Bob Moler with Ephemeris for Monday, May 4th. Today the Sun will be up for 14 hours and 23 minutes, setting at 8:51, and it will rise tomorrow at 6:26. The Moon, 3 days past full, will rise at 12:25 tomorrow morning.

The May evening sky, when it finally gets dark, contains fewer stars than those of winter. And they’re much dimmer. The main reason for that is that we are looking out the plane of the Milky Way Galaxy. The Milky Way is no nowhere to be seen, because it rings the horizon. A bit is visible in the north. The summer triangle of bright stars is not completely up in the evening, and it straddles the Milky Way. So we are looking out to the universe beyond the Milky Way, for the most part. Even amateur telescopes will reveal a great number of galaxies, because there’s a huge cluster of galaxies in the constellation Virgo which is right behind and below Leo the lion in the sky. However, just about 90° from the plane of the Milky Way is a star cluster that looks like strands of hair.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

May sky dome for 11 PM May 15th, showing constellations and deep sky objects. It shows how galaxies dominate the spring sky.
May sky dome for 11 PM May 15th, showing constellations and deep sky objects. It shows how galaxies dominate the spring sky. The tiny red circles are galaxies, other Milky Ways beyond our own. The other symbols are also what we call deep sky objects, that are extended objects among and beyond the solar system, such as star clusters, nebulae and galaxies. Most of the other symbols cluster around the plane of the Milky Way, that can be seen along the northern half of the horizon. The little orange circles are galactic or open star clusters which are relatively young and born out of the nebulae (red squares) in the the galactic plane. The green circles with the cross inside are globular star clusters which are very old and compact and are aranged within a large spherical volume concentrated on the center of the Milky Way. The green circles will line through it are planetary nebulae which have nothing to do with planets but are dying stars who puffed out their outer layers of gas. Created using Cartes du Ciel (Sky Charts).
Categories: Ephemeris Program, Galaxies, Milky Way

Ephemeris: 05/01/2026 – Previewing May skies

May 1, 2026 Comments off

This is Ephemeris for Friday, May 1st. Today the Sun will be up for 14 hours and 15 minutes, setting at 8:47, and it will rise tomorrow at 6:31. The Moon, at full today, will rise at 9:17 this evening.

Before we look at the month of May’s skies, consider that it’s May Day, a Cross-Quarter day meaning that spring is about half over. Daylight hours in the Interlochen/Traverse City area will increase from 14 hours and 15 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, but the length of daylight will be a few minutes longer. Local apparent noon this month, when the Sun passes due south, will be about 1:38 p.m. The Eta Aquariid meteor shower will reach its peak on the 5th, but will be hindered by the bright moon.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

May Evening Star Chart

Star Chart for May 2026 (11 p.m. EDT, May 15, 2026). Created using my LookingUp app.

The planets and stars are plotted for the 15th at 11 p.m. EDT in the evening and 4:30 a.m. on the 16th 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 4:30 a.m. are for the night of the15/16th. For each week before then add ½ hour (28 minutes if you’re picky). For each week after then, 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 their weekly locations.

May Morning Star Chart

Star Chart for May Mornings
Star Chart for May mornings, 2026 (4:30 a.m. EDT, May 16, 2026). Created using my LookingUp app

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning Twilight Evening Twilight Dark Night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2026-05-01 4h37m 5h21m 22h02m 22h46m – – 100%
2026-05-02 4h35m 5h20m 22h04m 22h48m – – 98%
2026-05-03 4h33m 5h18m 22h05m 22h50m 22h50m 23h28m 94%
2026-05-04 4h30m 5h16m 22h07m 22h52m 22h52m – 89%
2026-05-05 4h28m 5h14m 22h08m 22h54m 22h54m 0h26m 83%
2026-05-06 4h26m 5h13m 22h10m 22h56m 22h56m 1h15m 75%
2026-05-07 4h24m 5h11m 22h11m 22h58m 22h58m 1h56m 67%
2026-05-08 4h22m 5h09m 22h13m 23h00m 23h00m 2h29m 57%
2026-05-09 4h20m 5h08m 22h15m 23h02m 23h02m 2h55m 47%
2026-05-10 4h18m 5h06m 22h16m 23h04m 23h04m 3h18m 37%
2026-05-11 4h16m 5h04m 22h18m 23h06m 23h06m 3h38m 27%
2026-05-12 4h14m 5h03m 22h19m 23h08m 23h08m 3h57m 18%
2026-05-13 4h12m 5h01m 22h21m 23h10m 23h10m 4h12m 10%
2026-05-14 4h10m 5h00m 22h22m 23h12m 23h12m 4h10m 4%
2026-05-15 4h08m 4h58m 22h24m 23h14m 23h14m 4h08m 1%
2026-05-16 4h06m 4h57m 22h25m 23h16m 23h16m 4h06m 0%
2026-05-17 4h04m 4h55m 22h27m 23h18m 23h18m 4h04m 3%
2026-05-18 4h02m 4h54m 22h28m 23h20m – 4h02m 8%
2026-05-19 4h00m 4h53m 22h30m 23h22m 0h08m 4h00m 16%
2026-05-20 3h58m 4h51m 22h31m 23h24m 1h01m 3h58m 26%
2026-05-21 3h57m 4h50m 22h33m 23h26m 1h41m 3h57m 36%
2026-05-22 3h55m 4h49m 22h34m 23h28m 2h11m 3h55m 47%
2026-05-23 3h53m 4h48m 22h35m 23h30m 2h35m 3h53m 58%
2026-05-24 3h51m 4h46m 22h37m 23h32m 2h55m 3h51m 68%
2026-05-25 3h50m 4h45m 22h38m 23h33m 3h13m 3h50m 77%
2026-05-26 3h48m 4h44m 22h39m 23h35m 3h30m 3h48m 85%
2026-05-27 3h47m 4h43m 22h41m 23h37m – – 91%
2026-05-28 3h45m 4h42m 22h42m 23h39m – – 96%
2026-05-29 3h44m 4h41m 22h43m 23h41m – – 99%
2026-05-30 3h42m 4h40m 22h44m 23h42m – – 100%
2026-05-31 3h41m 4h39m 22h46m 23h44m – – 99%

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.blog/2018/09/27/.

NASA Calendar of Planetary Events

May  1  Fr            Venus: 27.8° E
     1  Fr   1:23 PM  Full Moon
     1  Fr   8:59 PM  Venus-Aldebaran: 6.4° N
     3  Su  10:20 PM  Moon-Antares: 0.5° N
     4  Mo   6:30 PM  Moon Apogee: 405800 km
     5  Tu   4:16 AM  Eta Aquariid Shower: ZHR = 60
     5  Tu   7:35 AM  Moon South Dec.: 28.1° S
     9  Sa   5:11 PM  Last Quarter
    11  Mo  12:36 AM  Moon Ascending Node
    14  Th  10:15 AM  Mercury Superior Conjunction
    16  Sa   4:01 PM  New Moon
    17  Su   9:48 AM  Moon Perigee: 358100 km
    18  Mo   3:38 PM  Moon North Dec.: 28.1° N
    18  Mo   9:50 PM  Moon-Venus: 2.9° S
    20  We   8:39 AM  Moon-Jupiter: 3.1° S
    21  Th  10:39 AM  Moon-Beehive: 0.8° S
    22  Fr  11:56 AM  Uranus Conjunction
    23  Sa   2:40 AM  Moon-Regulus: 0°
    23  Sa   7:11 AM  First Quarter
    23  Sa  11:26 AM  Moon Descending Node
    27  We  10:09 AM  Moon-Spica: 2.1° N
    31  Su   4:32 AM  Moon-Antares: 0.4° N
    31  Su   4:45 AM  Full Moon
Jun  1  Mo            Venus: 35° 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, 2026    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Fri  1| 06:32a  08:47p  14:15 | 10:00p  05:20a |Full  Rise 09:17p  100%|
|Sat  2| 06:31a  08:49p  14:17 | 10:01p  05:18a |      Rise 10:24p   98%|
+------+-----------------------+----------------+-----------------------+
|Sun  3| 06:29a  08:50p  14:20 | 10:03p  05:17a |      Rise 11:28p   95%|
|Mon  4| 06:28a  08:51p  14:23 | 10:04p  05:15a |      Rise 12:25a   90%|
|Tue  5| 06:26a  08:52p  14:25 | 10:06p  05:13a |      Rise 01:15a   84%|
|Wed  6| 06:25a  08:53p  14:28 | 10:08p  05:11a |      Rise 01:55a   77%|
|Thu  7| 06:24a  08:55p  14:30 | 10:09p  05:10a |      Rise 02:28a   68%|
|Fri  8| 06:22a  08:56p  14:33 | 10:11p  05:08a |      Rise 02:55a   59%|
|Sat  9| 06:21a  08:57p  14:35 | 10:12p  05:06a |L Qtr Rise 03:18a   49%|
+------+-----------------------+----------------+-----------------------+
|Sun 10| 06:20a  08:58p  14:38 | 10:14p  05:05a |      Rise 03:38a   39%|
|Mon 11| 06:19a  08:59p  14:40 | 10:15p  05:03a |      Rise 03:57a   29%|
|Tue 12| 06:17a  09:01p  14:43 | 10:17p  05:02a |      Rise 04:16a   19%|
|Wed 13| 06:16a  09:02p  14:45 | 10:18p  05:00a |      Rise 04:37a   11%|
|Thu 14| 06:15a  09:03p  14:47 | 10:20p  04:58a |      Rise 05:02a    5%|
|Fri 15| 06:14a  09:04p  14:49 | 10:21p  04:57a |      Rise 05:34a    1%|
|Sat 16| 06:13a  09:05p  14:52 | 10:23p  04:56a |New   Set  09:36p    0%|
+------+-----------------------+----------------+-----------------------+
|Sun 17| 06:12a  09:06p  14:54 | 10:24p  04:54a |      Set  10:57p    2%|
|Mon 18| 06:11a  09:07p  14:56 | 10:26p  04:53a |      Set  12:07a    7%|
|Tue 19| 06:10a  09:08p  14:58 | 10:27p  04:51a |      Set  01:01a   15%|
|Wed 20| 06:09a  09:09p  15:00 | 10:29p  04:50a |      Set  01:41a   24%|
|Thu 21| 06:08a  09:11p  15:02 | 10:30p  04:49a |      Set  02:11a   34%|
|Fri 22| 06:07a  09:12p  15:04 | 10:32p  04:47a |      Set  02:35a   45%|
|Sat 23| 06:06a  09:13p  15:06 | 10:33p  04:46a |F Qtr Set  02:54a   56%|
+------+-----------------------+----------------+-----------------------+
|Sun 24| 06:05a  09:14p  15:08 | 10:34p  04:45a |      Set  03:12a   66%|
|Mon 25| 06:05a  09:15p  15:10 | 10:36p  04:44a |      Set  03:30a   75%|
|Tue 26| 06:04a  09:16p  15:11 | 10:37p  04:43a |      Set  03:48a   83%|
|Wed 27| 06:03a  09:17p  15:13 | 10:38p  04:42a |      Set  04:08a   90%|
|Thu 28| 06:02a  09:17p  15:15 | 10:40p  04:41a |      Set  04:32a   95%|
|Fri 29| 06:02a  09:18p  15:16 | 10:41p  04:40a |      Set  05:01a   98%|
|Sat 30| 06:01a  09:19p  15:18 | 10:42p  04:39a |      Set  05:37a  100%|
+------+-----------------------+----------------+-----------------------+
|Sun 31| 06:00a  09:20p  15:19 | 10:43p  04:38a |Full  Rise 10:19p   99%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

Created using my LookingUp for DOS app.

Categories: Ephemeris Program, Month preview Tags:

Ephemeris: 04/30/2026 – GTAS meeting tomorrow, The Space Race.

April 30, 2026 Comments off

This is Ephemeris for Thursday, April 30th. Today the Sun will be up for 14 hours and 12 minutes, setting at 8:46, and it will rise tomorrow at 6:32. The Moon, 1 day before full, will set at 6:03 tomorrow morning.

The Grand Traverse Astronomical Society will host its May meeting tomorrow, May 1st at 9 PM at Northwestern Michigan College’s Joseph H Rogers Observatory. The later meeting time through July allows us to have viewing after the meeting start in darker skies. The program is a video called the Space Race. I’m not sure if it was the one 6 decades ago in the 1960s or the current one, which is in doubt. It will be informative either way. Afterward, about 10 PM if it’s clear, there will be viewing of the heavens through the observatory’s telescopes, featuring Jupiter, its cloud bands and moons. The observatory is located on Birmley Rd. South of Traverse City. Also, available on ZOOM, see gtastro.org.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

Maybe we can contrast the 1960s space race with the 2020s. There are differences on many levels.
Maybe we can contrast the 1960s space race with the 2020s. There are differences on many levels.
Categories: Ephemeris Program, GTAS Outreach Event, Space Race Tags:

Ephemeris: 04/29/2026 – Taking our weekly look at the whereabouts of the naked-eye planets

April 29, 2026 Comments off

This is Ephemeris for Wednesday, April 29th. Today the Sun will be up for 14 hours and 9 minutes, setting at 8:45, and it will rise tomorrow at 6:34. The Moon, 2 days before full, will set at 5:42 tomorrow morning.

Let’s take our weekly look at the whereabouts of the naked-eye planets. By 9:30 PM tonight or about 45 minutes or so after sunset, Venus may be seen very low in the West. A telescope will show a very tiny disc on Venus, because it is still pretty much beyond the Sun, 136 million miles (217 million kilometers) away from us. Over the next 6 months it will be moving closer to us and becoming much larger. Jupiter is the brilliant star-like object in the western before 10 PM. It is above and left of the brighter Venus. Venus will set at 11:11 PM, while Jupiter will hold out until 2:12 AM. Meanwhile, Mercury, Mars and Saturn are breaking up just west of the Sun, but are still overwhelmed by bright morning twilight.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

Looking west to Jupiter, and Venus with fading winter stars at 9:30 PM tonight, April 29, 2026. Jupiter and Venus are appearing to approach each other. They will be in conjunction on the evening of June 8th.
Jupiter, and Venus with fading winter stars at 9:30 PM tonight, April 29, 2026. Jupiter and Venus are appearing to approach each other. They will be in conjunction on the evening of June 8th. Created using Stellarium.
The Moon, 2 days before full, as seen at 10 PM tonight, April 29, 2026. A view visible in small telescopes showing an image with and without selected features labeled. Created using Stellarium, LibreOffice Draw, and GIMP.
Telescopic Jupiter and Venus as they would be seen in a small telescope with the same magnification.
Telescopic Jupiter and Venus (north up) as they would be seen in a small telescope with the same magnification. Venus will be visible for a short time near the western horizon, while Jupiter will be visible until after midnight. Venus’ apparent diameter will be 11.6″, and be 88.2% illuminated. It’s on the far side of the Sun. Jupiter will be 35.7″ in diameter, with its moons shown here for 10 PM, tonight April 29, 2026. The moons can shift noticably over an hour, especially Io and Europa. The (”) symbol means seconds of arc, or 1/3600th of a degree. Created using Cartes du Ciel (Sky Charts), LibreOffice Draw and GIMP.
The naked-eye planets at sunset and sunrise on a single night.
The naked-eye planets at sunset and sunrise on a single night, starting with sunset on the right on April 29, 2026. The night ends on the left with sunrise on the 30th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
A low precision ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, April 29 and 30th, 2026.
This is a low precision ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, April 29 and 30th, 2026. Some of the columns are self-explanatory, others are not. The transit column is the time that the body crosses the meridian and is due south. Elong, for elongation, is the angle between the Sun and that body. RA is right ascension, which is the object’s east-west position on the celestial sphere in hours and minutes. Dec is declination which is the north-south position of the object on the celestial sphere in degrees and minutes. R is the distance of that object from the Sun in astronomical units. An astronomical unit is about 93 million miles or 150 million kilometers. And Delta is the distance of that object from the Earth, also in astronomical units. I omit the ‘m’ in am and pm for compactness. The data was generated using my LookingUp for DOS app and displayed as a table by my Ephemeris Helper app.
Categories: Ephemeris Program, Naked-eye planets, Observing Tags: , , , , ,

Ephemeris: 04/28/2026 – Stars spend most of their lives fueled by hydrogen

April 28, 2026 Comments off

This is Ephemeris for Tuesday, April 28th. Today the Sun will be up for 14 hours and 7 minutes, setting at 8:44, and it will rise tomorrow at 6:35. The Moon, 3 days before full, will set at 5:24 tomorrow morning.

A star is a gaseous ball made mostly of hydrogen, which due to its mass crushes down in its core to create heat in the millions of degrees. Under those temperatures and pressures hydrogen nuclei, stripped of their electrons can collide to convert into helium and in doing so lose a tiny bit of mass that turns into energy which is used to sustain the star’s light and keep it stable. This hydrogen burning, so to speak, takes place during the longest period of a star’s life. And stars have a characteristic color based on their mass. Stars with little mass are cooler and appear a dim red. We call them red dwarfs. The nearest star to our solar system is a red dwarf called Proxima Centauri. It’s so dim that it’d be difficult to find with a pair of binoculars. And it’s only four light years away.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

H-R diagram
The Hertzsprung-Russell (H-R) diagram of star luminosity vs. surface temperature. Credit: European Southern Observatory (ESO).

The HR diagram above shows the various types and brightness of stars. The relatively thin line of stars from upper left to lower right, called the main sequence, are stars that are running primarily on hydrogen as a fuel. At the bottom end of the main sequence small stars with a fraction of the sun’s mass. All these stars are near the sun. It doesn’t mean that we live in a bad neighborhood, but that the most numerous stars are red dwarfs, and we just can’t see them when they’re farther away. All the other stars are not using as hydrogen as their main fuel source. Stars the upper right are using heavier elements to produce energy from the fusion products of lighter elements, after having run out of hydrogen in their cores. The white dwarf stars in the lower part of the diagram no longer have active thermonuclear reactions in their cores and are cooling down and collapsing. A star with the mass of the sun, when it becomes a white dwarf, will shrink down to about the size of the earth.

Categories: Concepts, Ephemeris Program, Stars Tags: , ,

Ephemeris: 04/27/2026 – Mare Orientale made a splash!

April 27, 2026 Comments off

This is Ephemeris for Monday, April 27th. Today the Sun will be up for 14 hours and 4 minutes, setting at 8:42, and it will rise tomorrow at 6:37. The Moon, halfway from first quarter to full, will set at 5:06 tomorrow morning.

One of the pictures that the astronauts of Artemis 2 took of the far side of the moon was one that revealed chains of craters which appear to be emanating from the Sea on the edge of what we can see on the moon from the Earth, called Mare Orientale or the Eastern Sea. It was created by the impact of an asteroid onto the Moon’s surface, maybe 4 billion years ago, kicking out debris in all directions. Apparently the ejecta thrown out created chains of craters that appear to trace back to Orientale. They are most easily seen to the north and west of Orientale towards the terminator, the sunrise line, where the shadows are deeper. There’s probably chains of craters going in other directions, but they have no shadows.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

Addendum

Crater chains that can be traced back to Mare Orientale. Credit: NASA/CSA/Artemis II Crew

Categories: Artemis Program, Ephemeris Program, The Moon Tags: , ,