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Ephemeris: 07/03/2024 – Where have the naked-eye planets wandered off to this week?

July 3, 2024 Comments off

This is Ephemeris for Wednesday, July 3rd. Today the Sun will be up for 15 hours and 28 minutes, setting at 9:31, and it will rise tomorrow at 6:03. The Moon, 2 days before new, will rise at 4:13 tomorrow morning.

Let’s find out where the naked-eye planets have wandered off to this week,. Venus is too close to the direction of the Sun to be seen. Mercury just might be seen very low in the west-northwest by 10 pm or so. Venus will appear in the evening sky next month. By 5:15 tomorrow morning, or about 45 minutes before sunrise, Saturn will be in the south-southeast and Mars will be lower in the east, and Jupiter will be low in the east-northeast. The skinny waning crescent Moon may be seen halfway between Jupiter and the northeastern horizon. Saturn will be a bit dimmer this year and next due to its rings being nearly edge on to us and not reflecting as much light. Saturn will rise at 12:40 am, Mars at 2:48 am, and Jupiter at 3:51 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

Mercury and Venus in the evening sky 1/2 an hour after sunset or 10 PM according to Stellarium . Spotting Mercury will be a real challenge and probably require binoculars. This is not a good elongation of Mercury for observers in the northern hemisphere so don’t worry if you can’t spot it. Venus, basically, is too close to the horizon to be spotted. Created using Stellarium.
The morning planets and the Moon are spread out from the east-northeast to the south in the morning sky at 5:15 AM, or about 45 minutes before sunrise, July 4, 2024. Also visible is the bright star Capella. Created using Stellarium.
This is the Moon according to Stellarium a day before new as it might appear tomorrow morning, July 4th 2024. The night side of the Moon will appear to be illuminated by earthshine, the reflection of the Sun’s light from off the Earth in the Moon’s sky. Created using Stellarium.
Telescopic Saturn and Jupiter (north up) as they would be seen in a small telescope at 5 AM July 4th 2024 with the same magnification. Apparent diameters: Saturn 18.0″, its rings 41.9″; Mars, too small to be represented here, is 5.4″; Jupiter 33.7″. Note the ” means seconds of arc, or 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 July 3, 2024. The night ends on the left with sunrise on the 4th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
This is an ephemeris of the Sun Moon and naked eye planet positions for today and tomorrow, July 3rd and 4th 2024. Some of the columns are self-explanatory, others 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. Dec is declination which is the north-south position of the object on the celestial sphere. The time of the positions is 8 pm EDT, (0 hr UT the next date). 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 by my Ephemeris Helper app.
Categories: Ephemeris Program, Naked-eye planets, Observing, Planets Tags: , , , , ,

Ephemeris Extra: 07/02/2024 – A closer look at Corona Borealis

July 2, 2024 Comments off

Adapted from an article that ran in the Stellar Sentinel, the July 2024 newsletter of the Grand Traverse Astronomical Society.

Corona Borealis in relation to some of its neighboring constellations and bright stars. Created using Stellarium.

A small constellation is getting a lot of attention this year because we expect a bright nova to appear in it sometime in the next few months. The constellation is Corona Borealis, the Northern Crown. It is a small constellation between the Boötes and the bright star Arcturus and Hercules, and farther off to the east the bright star Vega. Corona Borealis contains seven stars in the 2/3 circle of stars. Its brightest star is the third star from the right. It’s the second magnitude star called Alphecca. In Arabic, it means The Bright Star of the Broken Ring of Stars, which is a pretty good description of it. It is also known as Gemma though it sounds like a gem in a crown, it actually means blossom which would appear in a floral crown.

In Greek mythology the crown was given to the Princess Ariadne. The story goes like this. During the time of the Minoan civilization on Crete, It was ruled by King Minos, whose daughter was Ariadne. The Minoans apparently had defeated Athens in battle and had extracted tribute from them. That yearly tribute being the sacrifice of the young man or maiden to enter the Labyrinth which was home to a monster called the Minotaur. In this story a fellow by the name of Theseus from Athens was sent to Crete to face the Minotaur. He fell in love with Ariadne, but he had to enter the Labyrinth, so she provided him with a spool of thread so he could find his way back out again after he had slain the Minotaur, if he was able to. He entered the Labyrinth and found the Minotaur. Theseus was able to slay the beast, and was able to follow the thread back out. Theseus and Ariadne fled to the Island of Naxos where he married her. However, he soon abandoned her. As consolation, the god Dionysus gave her a crown. She kept the crown until she remarried, and it was placed in the sky where we see it today.

For the Anishinaabe native peoples of our area Corona Borealis becomes the Sweat Lodge. Other indigenous peoples of North America see these stars as circles of maidens, or other circles. To the Aborigines of Australia who see Corona Borealis very low in the north, it’s Woomera, the boomerang.

The location and expected brightness of T Coronae Borealis (T CrB) when it goes nova later this year.


The constellation has two famous variable stars. The one we’re expecting to flare up this year, up to second magnitude as a nova, is T Coronae Borealis (T CrB), sometimes called the Blaze Star. It was recorded in 1866 and at even earlier times, and was naked eye for eight days, dropping a half magnitude per day. It also blazed forth in 1946, making it one of the few known recurrent novas. In 1946 the star, normally 10th magnitude, barely visible in binoculars, underwent a slight dimming about 11 months before it blazed forth as a nova. This has already happened last year, so we are expecting it soon to blaze forth again. It will appear to the lower left, just outside the circle of stars in the crown, and will grow as bright as Alphecca.

Novas, also in the case of T CrB, are close binary stars containing a large star and a white dwarf. A white dwarf is a star at the end of its life, and has run out of hydrogen or other light elements in its core to keep it sustained. So it shrinks down to about the size of the Earth, even though it has the mass of the Sun or a little more. It orbits with the larger star and is basically siphoning off gas from that large star onto its surface, enough gases accumulate on the star for a thermonuclear reaction to occur, and it becomes a nova, brightening thousands of times for a few days. The white dwarf survives to do it all over again in some cases.

Corona Borealis, pointing out the location of variable stars R CrB and T CrB. Created using Stellarium.

Corona Borealis’ other famous variable star is R Coronae Borealis, a star that’s normally about 6th magnitude that irregularly dips down to 10th or even dimmer. The mechanism for this appears to be that the star is surrounded by clouds of dust that periodically block it from our view.

If you’re interested in observing variable stars, check out the American Association of Variable Star Observers: https://www.aavso.org/

Corona Australis finder
Corona Australis finder chart, for around midnight August 2nd.

If there’s a Northern Crown, there should be a Southern Crown, and there is. It is Corona Australis made of dim stars, and it is located just below the constellation of Sagittarius, right below the Teapot asterism, which is very low on our southern horizon after midnight this month, but better seen in August.

Categories: Constellations, Ephemeris Extra, Mythology, Nova

Ephemeris: 7/02/2024 – Antares and the scorpion

July 2, 2024 Comments off

This is Bob Moler with Ephemeris for Tuesday, July 2nd. Today the Sun will be up for 15 hours and 29 minutes, setting at 9:31, and it will rise tomorrow at 6:02. The Moon, 3 days before new, will rise at 3:26 tomorrow morning.

The constellation of Scorpius the scorpion is low in the south at 11 PM these nights. It’s bright star Antares will pass due south at 11:30 this evening. Antares is an interesting star in that it is a red giant star, and its name Antares* means “Rival of Mars” alluding to the fact that it and Mars appears to be the same color. And about every two years Mars passes near Antares, so unless you know your stars and planets you could mistake them for each other. Antares lies at the heart of the scorpion. To its upper right is the front part of its body and claws, and the trail of stars running down the other way, nearly to the horizon, in the south and back up in the south-southeast to the two stars of its stinger make its characteristic tail.

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.

*Breaking down Antares: Ant (Anti, against) – Ares (The Greek god of war the Romans called Mars).

Addendum

Scorpius Finder in four frames
Scorpius Finder in four frames. The 1st frame is the star field above the southern horizon as it might appear at 11 pm, July 2nd. The 2nd frame shows the constellation lines of Scorpius. I differ a bit from Stellarium in the lines above right of Antares. The 3rd frame is the constellation art that comes with Stellarium of Scorpius. The 4th frame is the star field again with the constellation lines, but seen without the horizon or atmospheric extinction getting in the way. The Arabs may have thought Scorpius was a larger constellation. There are two stars at the upper right corner of the frame that they saw belonged to Scorpius, which now belong to Libra. The upper one, nearest the top, is Zubeneschamali which means northern claw. The one below it and nearest the right edge of the image is Zubenelgenubi, the southern claw. These names predate Libra being its own constellation.

Note for trivia fans: Zubeneschamali is the longest star name at 14 letters.

Categories: Constellations, Observing Tags: ,

Ephemeris: 07/01/2024 – Previewing July’s skies

July 1, 2024 Comments off

This is Bob Moler with Ephemeris for Monday, July 1st. Today the Sun will be up for 15 hours and 30 minutes, setting at 9:31, and it will rise tomorrow at 6:02. The Moon, 3 days past last quarter, will rise at 2:50 tomorrow morning.

Let’s preview July’s skies. The Sun, having reached its northern solstice, is beginning to slide southward again, at first imperceptibly, then with greater speed. The daylight hours will decrease from 15 hours and 30 minutes today to 14 hours 40 minutes at month’s end. The daylight hours will be slightly shorter south of Interlochen, and slightly longer to the north. The altitude of the Sun at local noon, when it is due south will decrease from 68 degrees tomorrow to 63 degrees at month’s end. Despite the warmth, the Earth will reach its greatest distance from the Sun on Friday the 5th. Finally, a planet in the evening sky. Saturn will rise before midnight by mid-month, and Venus may be visible shortly after sunset by month’s end.

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

July Evening Star Chart

Star Chart for July 2024
Star Chart for July 2024 (11 p.m. EDT, July 15, 2024). 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.

July Morning Star Chart

Star Chart for July mornings, 2024
Star Chart for July mornings, 2024 (4 am EDT, July 15, 2024). 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.
  • The Summer Triangle is in red.
  • DAqR is the radiant of the South Delta Aquariid meteor shower (Peaks on the afternoon of the 27th)

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning Twilight Evening Twilight Dark Night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2024-07-01 3h35m 4h38m 23h00m 0h02m 0h02m 2h22m 0.16
2024-07-02 3h36m 4h38m 22h59m 0h01m 0h01m 2h51m 0.09
2024-07-03 3h37m 4h39m 22h59m 0h01m 0h01m 3h27m 0.04
2024-07-04 3h39m 4h40m 22h58m 0h00m 0h00m 3h39m 0.01
2024-07-05 3h40m 4h41m 22h58m 23h59m 23h59m 3h40m 0.00
2024-07-06 3h41m 4h42m 22h57m 23h58m 23h58m 3h41m 0.02
2024-07-07 3h43m 4h43m 22h56m 23h57m 23h57m 3h43m 0.05
2024-07-08 3h44m 4h44m 22h56m 23h55m 23h55m 3h44m 0.11
2024-07-09 3h46m 4h45m 22h55m 23h54m 23h54m 3h46m 0.17
2024-07-10 3h47m 4h46m 22h54m 23h53m – 3h47m 0.25
2024-07-11 3h49m 4h47m 22h53m 23h52m 0h11m 3h49m 0.34
2024-07-12 3h51m 4h48m 22h52m 23h50m 0h27m 3h51m 0.43
2024-07-13 3h52m 4h50m 22h51m 23h49m 0h42m 3h52m 0.53
2024-07-14 3h54m 4h51m 22h50m 23h47m 0h59m 3h54m 0.62
2024-07-15 3h56m 4h52m 22h49m 23h46m 1h18m 3h56m 0.71
2024-07-16 3h58m 4h53m 22h48m 23h44m 1h41m 3h58m 0.80
2024-07-17 3h59m 4h55m 22h47m 23h42m 2h10m 3h59m 0.88
2024-07-18 4h01m 4h56m 22h46m 23h41m 2h49m 4h01m 0.94
2024-07-19 4h03m 4h57m 22h45m 23h39m 3h41m 4h03m 0.98
2024-07-20 4h05m 4h59m 22h44m 23h37m – – 1.00
2024-07-21 4h07m 5h00m 22h42m 23h36m – – 0.99
2024-07-22 4h09m 5h01m 22h41m 23h34m – – 0.96
2024-07-23 4h10m 5h03m 22h40m 23h32m – – 0.90
2024-07-24 4h12m 5h04m 22h38m 23h30m – – 0.81
2024-07-25 4h14m 5h06m 22h37m 23h28m 23h28m 23h43m 0.71
2024-07-26 4h16m 5h07m 22h35m 23h26m 23h26m – 0.60
2024-07-27 4h18m 5h08m 22h34m 23h24m 23h24m 0h03m 0.49
2024-07-28 4h20m 5h10m 22h32m 23h22m 23h22m 0h26m 0.38
2024-07-29 4h22m 5h11m 22h31m 23h20m 23h20m 0h53m 0.28
2024-07-30 4h24m 5h13m 22h29m 23h18m 23h18m 1h26m 0.18
2024-07-31 4h26m 5h14m 22h28m 23h16m 23h16m 2h08m 0.11

Twilight calendar was generated using Cartes du Ciel (Sky Charts).

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

Jul  1  Mo            Venus: 7.4° E
     1  Mo   2:27 pm  Moon-Mars: 4.2° S
     2  Tu  11:31 am  Moon-Pleiades:  .3° N
     4  Th   8:08 pm  Moon North Dec.: 28.4° N
     5  Fr   1:59 am  Aphelion: 1.0167 AU
     5  Fr   6:57 pm  New Moon
     6  Sa   5:12 pm  Mercury-Beehive:  .1° S
     7  Su  12:04 pm  Moon-Beehive: 3.3° S
     7  Su   2:33 pm  Moon-Mercury: 3.5° S
     8  Mo   4:14 am  Jupiter-Aldebaran: 4.8° N
    12  Fr   4:12 am  Moon Apogee: 404400 km
    12  Fr   6:27 pm  Moon Descending Node
    13  Sa   6:49 pm  First Quarter
    13  Sa   9:48 pm  Moon-Spica: 1° S
    17  We   3:37 pm  Moon-Antares:  .2° S
    19  Fr   6:59 am  Moon South Dec.: 28.4° S
    20  Sa   3:35 pm  Mars-Pleiades: 4.8° S
    21  Su   6:17 am  Full Moon
    22  Mo   2:59 am  Mercury Elongation: 26.9° E
    24  We   1:43 am  Moon Perigee: 364900 km
    24  We   4:38 pm  Moon-Saturn:  .4° S
    24  We   9:40 pm  Mercury-Regulus: 2° S
    26  Fr   1:33 am  Moon Ascending Node
    27  Sa   5:44 pm  Delta Aquarid Shower: ZHR = 20
    27  Sa  10:52 pm  Last Quarter
    29  Mo   5:13 pm  Moon-Pleiades:  .1° N
Aug  1  Th            Venus: 15.9° E

All event times are given for UTC-4:00 Eastern Daylight Saving Time thereafter.

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html

If you go to the above site you can print out a list like the above for the entire year or calendar pages for your time zone.

Note that the site is now kept up for archival purposes. Fred Espenak retired from NASA several years ago and has his own site, AstroPixels, which contain the same information: http://astropixels.com/almanac/almanac.html. However it uses standard time all year.

Sun and Moon Rising and Setting Events

LU             Ephemeris of Sky Events for Interlochen/TC
July, 2024    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Mon  1| 06:01a  09:31p  15:30 | 10:57p  04:36a |      Rise 02:50a   18%|
|Tue  2| 06:02a  09:31p  15:29 | 10:56p  04:36a |      Rise 03:26a   10%|
|Wed  3| 06:02a  09:31p  15:28 | 10:56p  04:37a |      Rise 04:13a    5%|
|Thu  4| 06:03a  09:31p  15:27 | 10:55p  04:38a |      Rise 05:10a    1%|
|Fri  5| 06:03a  09:30p  15:26 | 10:55p  04:39a |New   Set  09:59p    0%|
|Sat  6| 06:04a  09:30p  15:25 | 10:54p  04:40a |      Set  10:39p    1%|
+------+-----------------------+----------------+-----------------------+
|Sun  7| 06:05a  09:29p  15:24 | 10:53p  04:41a |      Set  11:10p    5%|
|Mon  8| 06:06a  09:29p  15:23 | 10:53p  04:42a |      Set  11:34p    9%|
|Tue  9| 06:06a  09:29p  15:22 | 10:52p  04:43a |      Set  11:53p   16%|
|Wed 10| 06:07a  09:28p  15:20 | 10:51p  04:44a |      Set  12:10a   23%|
|Thu 11| 06:08a  09:27p  15:19 | 10:50p  04:45a |      Set  12:26a   32%|
|Fri 12| 06:09a  09:27p  15:17 | 10:49p  04:46a |      Set  12:42a   41%|
|Sat 13| 06:10a  09:26p  15:16 | 10:48p  04:47a |F Qtr Set  12:58a   50%|
+------+-----------------------+----------------+-----------------------+
|Sun 14| 06:11a  09:25p  15:14 | 10:47p  04:49a |      Set  01:17a   60%|
|Mon 15| 06:12a  09:25p  15:13 | 10:46p  04:50a |      Set  01:40a   69%|
|Tue 16| 06:12a  09:24p  15:11 | 10:45p  04:51a |      Set  02:10a   78%|
|Wed 17| 06:13a  09:23p  15:09 | 10:44p  04:52a |      Set  02:49a   86%|
|Thu 18| 06:14a  09:22p  15:07 | 10:43p  04:54a |      Set  03:40a   92%|
|Fri 19| 06:15a  09:21p  15:06 | 10:41p  04:55a |      Set  04:45a   97%|
|Sat 20| 06:16a  09:21p  15:04 | 10:40p  04:56a |      Set  06:01a  100%|
+------+-----------------------+----------------+-----------------------+
|Sun 21| 06:17a  09:20p  15:02 | 10:39p  04:58a |Full  Rise 10:07p   99%|
|Mon 22| 06:18a  09:19p  15:00 | 10:38p  04:59a |      Rise 10:37p   97%|
|Tue 23| 06:19a  09:18p  14:58 | 10:36p  05:00a |      Rise 11:01p   91%|
|Wed 24| 06:20a  09:17p  14:56 | 10:35p  05:02a |      Rise 11:23p   83%|
|Thu 25| 06:21a  09:16p  14:54 | 10:33p  05:03a |      Rise 11:43p   74%|
|Fri 26| 06:23a  09:14p  14:51 | 10:32p  05:05a |      Rise 12:03a   63%|
|Sat 27| 06:24a  09:13p  14:49 | 10:30p  05:06a |L Qtr Rise 12:26a   51%|
+------+-----------------------+----------------+-----------------------+
|Sun 28| 06:25a  09:12p  14:47 | 10:29p  05:08a |      Rise 12:52a   40%|
|Mon 29| 06:26a  09:11p  14:45 | 10:27p  05:09a |      Rise 01:26a   30%|
|Tue 30| 06:27a  09:10p  14:42 | 10:26p  05:11a |      Rise 02:08a   20%|
|Wed 31| 06:28a  09:09p  14:40 | 10:24p  05:12a |      Rise 03:01a   12%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunset and sunrise

Generated using my LookingUp for DOS app.

Categories: Ephemeris Program, Month preview Tags: