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06/30/2023 – Ephemeris – Previewing July’s skies

June 30, 2023 Comments off

This is Bob Moler with Ephemeris for International Asteroid Day, Friday, June 30th. Today the Sun will be up for 15 hours and 31 minutes, setting at 9:32, and it will rise tomorrow at 6:01. The Moon, 3 days before full, will set at 3:45 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 31 minutes tomorrow to 14 hours 42 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 now to 63 degrees at month’s end. The Sun will be a degree lower in the Straits area. Despite the warmth, the Earth will reach its greatest distance from the Sun next Thursday, the 6th. On that day, the Earth will reach 94.5 million miles (152.1 million kilometers) from 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

July Evening Star Chart

Star Chart for July 2023 (11 p.m. EDT, July 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.

July Morning Star Chart

Star Chart for July mornings, 2023 (4 am EDT, July 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.
  • The Summer Triangle is in red.
  • DAqR is the radiant of the South Delta Aquariid meteor shower (Peaks on the morning of the 28th)

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning Twilight Evening Twilight Dark Night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2023-07-01 3h38m 4h41m 23h00m 0h03m – – 0.98
2023-07-02 3h39m 4h42m 23h00m 0h02m – – 1.00
2023-07-03 3h40m 4h43m 22h59m 0h01m – – 0.99
2023-07-04 3h42m 4h43m 22h59m 0h00m – – 0.96
2023-07-05 3h43m 4h44m 22h58m 0h00m – – 0.89
2023-07-06 3h44m 4h45m 22h58m 23h59m 23h59m – 0.81
2023-07-07 3h46m 4h46m 22h57m 23h57m 23h57m 0h16m 0.71
2023-07-08 3h47m 4h47m 22h56m 23h56m 23h56m 0h39m 0.60
2023-07-09 3h49m 4h48m 22h56m 23h55m 23h55m 0h59m 0.49
2023-07-10 3h50m 4h49m 22h55m 23h54m 23h54m 1h19m 0.38
2023-07-11 3h52m 4h50m 22h54m 23h53m 23h53m 1h40m 0.28
2023-07-12 3h53m 4h52m 22h53m 23h51m 23h51m 2h03m 0.19
2023-07-13 3h55m 4h53m 22h52m 23h50m 23h50m 2h30m 0.12
2023-07-14 3h57m 4h54m 22h51m 23h48m 23h48m 3h04m 0.06
2023-07-15 3h58m 4h55m 22h50m 23h47m 23h47m 3h46m 0.02
2023-07-16 4h00m 4h56m 22h49m 23h45m 23h45m 4h00m 0.00
2023-07-17 4h02m 4h58m 22h48m 23h44m 23h44m 4h02m 0.00
2023-07-18 4h04m 4h59m 22h47m 23h42m 23h42m 4h04m 0.02
2023-07-19 4h05m 5h00m 22h46m 23h40m 23h40m 4h05m 0.05
2023-07-20 4h07m 5h02m 22h44m 23h39m 23h39m 4h07m 0.10
2023-07-21 4h09m 5h03m 22h43m 23h37m 23h37m 4h09m 0.17
2023-07-22 4h11m 5h04m 22h42m 23h35m 23h51m 4h11m 0.25
2023-07-23 4h13m 5h06m 22h41m 23h33m – 4h13m 0.33
2023-07-24 4h15m 5h07m 22h39m 23h31m 0h07m 4h15m 0.43
2023-07-25 4h17m 5h08m 22h38m 23h30m 0h25m 4h17m 0.53
2023-07-26 4h19m 5h10m 22h36m 23h28m 0h44m 4h19m 0.63
2023-07-27 4h21m 5h11m 22h35m 23h26m 1h08m 4h21m 0.73
2023-07-28 4h23m 5h13m 22h33m 23h24m 1h39m 4h23m 0.83
2023-07-29 4h24m 5h14m 22h32m 23h22m 2h19m 4h24m 0.90
2023-07-30 4h26m 5h16m 22h30m 23h20m 3h14m 4h26m 0.96
2023-07-31 4h28m 5h17m 22h29m 23h18m 4h24m 4h28m 0.99

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  Sa            Venus: 41.7° E
     1  Sa  12:46 am  Mercury Superior Conj.
     1  Sa   2:48 am  Venus-Mars: 3.6° N Quasi-conjunction
     1  Sa   3:20 am  Moon-Antares: 1.5° S
     2  Su   9:23 pm  Moon South Dec.: 27.8° S
     3  Mo   7:39 am  Full Buck Moon
     4  Tu   6:28 pm  Moon Perigee: 360,200 km
     6  Th   4:59 am  Aphelion: 1.0167 AU
     6  Th  11:05 pm  Moon-Saturn: 2.7° N
     7  Fr            Venus greatest brilliancy, magnitude -4.7
     9  Su   9:48 pm  Last Quarter
    10  Mo   1:18 am  Mars-Regulus:  0.6° N
    10  Mo   9:23 pm  Moon Ascending Node
    11  Tu   5:18 pm  Moon-Jupiter: 2.3° S
    13  Th   2:31 am  Moon-Pleiades: 1.8° N
    14  Fr   6:33 pm  Mercury-Beehive:  0.2° N
    15  Sa  10:40 pm  Moon North Dec.: 27.8° N
    16  Su   3:49 am  Venus-Regulus: 3.3° S
    17  Mo   2:32 pm  New Moon
    20  Th   2:56 am  Moon Apogee: 406,300 km
    20  Th  12:00 am  Moon-Mars: 3.6° S
    25  Tu  11:05 am  Moon Descending Node
    25  Tu   6:07 pm  First Quarter
    27  Th   7:00 am  Mercury-Venus: 5.1° N
    28  Fr  11:35 am  Delta Aquariid Shower: ZHR = 20
    28  Fr   1:11 pm  Moon-Antares: 1.3° S
    28  Fr   2:21 pm  Mercury-Regulus:  0.1° S
    30  Su   7:13 am  Moon South Dec.: 27.9° S
Aug  1  Tu            Venus: 18.7° E

All event times are given for UTC-5:00: Eastern Standard Time before the 14th or UTC-4:00 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.

NASA Calendar of Planetary 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 

Created using my LookingUp for DOS output as text.

Categories: Ephemeris Program, Month preview, Observing Tags:

06/29/2023 – Ephemeris – Learning about the Sun – sunspots

June 29, 2023 Comments off

This is Ephemeris for Thursday, June 29th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 6:00. The Moon, 3 days past first quarter, will set at 3:10 tomorrow morning.

The face of the Sun is populated, from time to time, with dark spots, simply called sunspots. It is rare that a sunspot or sunspot group is large enough to see with eclipse glasses. Sunspots normally form in groups, and are called active regions, because they are sites of solar flares, explosions that would put the world’s entire nuclear arsenals to shame in a single explosion. The bright ball of the Sun that is sometimes called a surface is called the photosphere, a region of the Sun, where the gases are of low enough density so the transportation of energy from the Sun’s core changes from convection to radiation. It is within this convective region that magnetic fields form that cool the gas, making it darker, by restricting their movement.

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 Sun in visible light, actually toward the red end of the visible spectrum, showing the photosphere with a large Sunspot group near the center around 21:30 last night, June 28, 2023. There are other sunspots visible. Also note the brighter areas, which are called faculae. Credit: NASA/SDO.

Other features of the photosphere are faculae (plural of facula), brighter areas of the photosphere, often associated with or are a precursor to sunspots. Faculae are best seen near the Sun’s limb (edge), as can be seen above. If the photosphere doesn’t appear smooth, that’s because it isn’t. The photosphere lies atop the convective zone of the Sun. The photosphere is populated by the tops of convection cells called granules, approximately 600 miles, or 1,000 kilometers wide and last only about 20 minutes.

From NASA/Marshall Solar Physics webpage.
Categories: Ephemeris Program, The Sun Tags: , , ,

06/28/2023 – Ephemeris – Let’s find out where the naked-eye planets have wandered off to this week

June 28, 2023 Comments off

This is Ephemeris for Wednesday, June 28th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 2 days past first quarter, will set at 2:43 tomorrow morning.

Let’s find out where the naked-eye planets have wandered off to this week. Venus is our blazing Evening Star, seen in the west all evening. It sets tonight at 11:51 pm, and three minutes earlier each night. The red planet Mars is seen left of and above Venus by around a third the width of one’s fist held at arm’s length. Venus is closing the gap between them, They will be closest this Saturday, before Venus pulls away. Their paths will not cross while they are in the evening sky. Mars is much fainter than Venus and difficult to spot in twilight. In the morning, Saturn will be visible in the south-southeast at 5 am, the brightest “star” in that direction. Jupiter will be low in the east at that hour. Jupiter is the brightest star-like object in the morning sky now.

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, Mars and bright star Regulus can be seen low in the west at 10:30 pm EDT tonight, June 28, 2023. Created using Stellarium.
The nearly 11 day old Moon (2 days past first quarter) as it might appear at 10:30 pm tonight, June 28, 2023. Created using Stellarium, LibreOffice Draw and GIMP.
Jupiter and Saturn seen at 5 am, about an hour before sunrise tomorrow morning, June 29, 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 June 28, 2023, for Venus and 5 am June 29, 2023, for Jupiter and Saturn.
Apparent diameters: Venus 32.52″ and is 33.6% illuminated; Saturn 17.99″, its rings 41.91″; Jupiter 36.41″. Mars, too small to be represented here, is 4.26″ in diameter. Venus, Saturn and Jupiter are approaching us, so their apparent diameters are growing. The ” symbol means seconds of arc (1/3600th of a degree.) Click or tap on the image to enlarge it. 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 June 28, 2023. The night ends on the left with sunrise on the 29th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
Categories: Ephemeris Program, Naked-eye planets, Planets Tags: , , , ,

06/27/2023 – Ephemeris – Preparing to view the upcoming solar eclipses safely

June 27, 2023 Comments off

This is Ephemeris for Tuesday, June 27th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 1 day past first quarter, will set at 2:21 tomorrow morning.

In preparation for the two solar eclipses that will be visible in North America in the next 10 months, I’m going to spend some time describing what the Sun is, and how it appears to us. First point: Never look at the Sun without proper and approved filters. Inexpensive eclipse glasses work fine for the partial phase of a solar eclipse. However, most features, like sunspots, are generally too small to be seen with them. Do not use these glasses with binoculars or a telescope. The plastic filters will melt through in a fraction of a second. Glass filters can shatter from the heat. The only safe solar filter for telescopes is one placed in front of the telescope tube, so it’s only exposed to ambient light and heat. If confused, just ask your local amateur astronomer.

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 eclipse glasses must contain a statement that it “Conforms to and meets the Transmission Requirements of ISO 12312-2, Filters for Direct Observation of the Sun.” Click or tap on the image to enlarge it.
This is a filter for a small telescope that must fit snugly in front of the telescope. I bought this for the 2017 total solar eclipse and have used it occasionally ever since. Note the tiny scratches. I will have to check it out to see if they affect the image. Even a tiny pinhole can ruin the view. It’s not that they are dangerous, unless it’s a really big one. A single pinhole can be covered up, but too many will ruin the view.
Categories: Ephemeris Program, Observing, Sun Tags: , , ,

06/26/2023 – Ephemeris – After the latest sunset, a look at the Moon

June 26, 2023 Comments off

This is Ephemeris for Monday, June 26th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, at first quarter today, will set at 2:02 tomorrow morning.

Tonight is the night of the latest sunset. From now to December 10th the Sun will be setting earlier than the night before. It won’t be noticeable at first, but the change will increase throughout the summer. The Moon actually arrived at first quarter phase early this morning, so by tonight it will appear slightly gibbous. The term gibbous actually means hump-backed, and the Moon will appear more so as it advances toward being fully illuminated a week from now. For me personally, I find that the best time to view the Moon with a telescope is within three or four days from its quarter phase, unless I’m looking at a specific feature. That’s when shadows are front and center on the moon. The Moon being gray on gray, shadows keep the Moon from appearing flat.

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 Moon, roughly 18 hours past first quarter tonight at 10:30 pm, June 26, 2023, with selected features labeled. I try, whenever possible, to center labels on the feature. Created using Stellarium, LibreOffice Draw and GIMP.
Categories: Concepts, Ephemeris Program, Observing, Phases, The Moon Tags: ,

06/23/2023 – Ephemeris – Sun and Star Party scheduled for tomorrow at the Sleeping Bear Dunes

June 23, 2023 Comments off

This is Ephemeris for Friday, June 23rd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, 3 days before first quarter, will set at 1:11 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 6 pm to 8 pm. The society has two hydrogen alpha solar telescopes to view the Sun’s chromosphere and prominences. Plus some members also have solar scopes also white light filtered telescopes to view sunspots on the face of the Sun. Night viewing will start at 10 pm with the Moon and Venus featured, along with the brighter telescopic wonders of early summer. The park rangers will leave at midnight, but society members can stay later to view the fainter wonders in the darkened sky. All this will happen only if clouds permit.

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

Observing the Sun at the Sleeping Bear Dunes National Lakeshore’s Dune Climb.
Dune Climb Setup
This in the beginning of setup for the October 21, 2017 star party at the dune climb. Taken early while there was enough light. The dune blocks up to 12 degrees from the southwest to northwest, but the rest of the horizon is quite low. Venus will be high enough to clear the dune for most of the evening.

The Dune Climb is not the place to view the spectacular sunset. The best place is from the Lake Michigan Overlook stop on Pierce Stocking Scenic Drive.

Categories: Ephemeris Program, Events, GTAS Outreach Event, Star Party Tags: , , ,

06/22/2023 – Ephemeris – The lunar seas on tonight’s Moon

June 22, 2023 Comments off

This is Ephemeris for Thursday, June 22nd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, halfway from new to first quarter, will set at 12:51 tomorrow morning.

The crescent Moon tonight reveals two large seas. Astronomers using the first telescopes thought the darker flat areas on the moon may actually be filled with water. It turns out that they are flat lava plains, and since most of them are roughly circular, may be gigantic craters from impacts of asteroids. Examination of rocks brought back by the Apollo astronauts over 50 years ago suggest the age of the seas at around 4 billion years. This suggests some kind of disruption in the solar system, called the Late Heavy Bombardment. The reason the Earth does not have these scars is due to plate tectonics and the weathering of wind and water. The Moon has none of these, so it preserves the damage done to it.

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 Moon 4 days after new. for 10:30 pm tonight June 22, 2023 or 2:30 UT on the 23rd. The large gray areas whose names start with Mare (pronounced Mar-e) are lunar seas. Created using Stellarium, LibreOffice and GIMP. Labels from Virtual Moon Atlas.

Late Heavy Bombardment (Based on my August 4, 2022 post)

There are even more and larger seas on the east half of the Moon, as we see it. Most were created about 3.9 billion years ago by asteroid strikes. The same thing happened to the Earth, but plate tectonics destroyed the evidence. Not so on the Moon. The result, many planetary scientists think, was the Late Heavy Bombardment, caused by the shifting orbits of mainly Saturn, Uranus and Neptune that disrupted the smaller asteroids, and sending them careening through the solar system.

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

06/21/2023 – Ephemeris – Let’s find out where the naked-eye planets have wandered off to this week

June 21, 2023 Comments off

This is Ephemeris for Wednesday, June 21st. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, 3 days past new, will set at 12:27 tomorrow morning.

Let’s find out where the naked-eye planets have wandered off to this week. Looking below the horizon we see our planet, which will reach the June solstice and the beginning of summer in the northern hemisphere later this morning (10:58 am EDT, 14:58 UT). Venus is our blazing Evening Star seen in the west all evening. It will still set after midnight, but barely. Tonight it is seen below the Moon. The red planet Mars is seen left of and a bit higher than Venus by four and a half degrees, or a bit less than half 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. Both Mars and Venus are in Cancer. In the morning, Saturn will be visible low in the south-southeast at 5 am. Jupiter will be low in the east 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

Venus, Mars and the thin crescent Moon to be seen at 10:30 pm EDT tonight, June 21, 2023. Created using Stellarium.
The moon as it might appear tonight, June 21, 2023, with selected features labeled. Created using Stellarium, LibreOffice Draw and GIMP.
Jupiter and Saturn seen at 5 am, about an hour before sunrise. 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 29.41″ and is 38.7% illuminated; Saturn 17.79″, its rings 41.44″; Jupiter 35.83″. Mars, too small to be represented here, is 4.35″ in diameter. Venus, Saturn and Jupiter are approaching us, so their apparent diameters are growing. 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 June 21, 2023. The night ends on the left with sunrise on the 22nd. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
Categories: Ephemeris Program, Observing, Planets Tags: , , , ,

06/20/2023 – Ephemeris – Summer starts tomorrow!

June 20, 2023 Comments off

This is Bob Moler with Ephemeris for Tuesday, June 20th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, 2 days past new, will set at 11:58 this evening.

Tomorrow is the day of the longest daylight hours, the summer solstice. The exact time of the summer solstice will occur at 10:58 am. One really can’t tell where the Sun is against the constellations and its eastward motion along the ecliptic because when the Sun’s out the sky is blue and the stars are invisible. However the ancients could notice that the Sun changed its height in the South over the year and the summer solstice was the time that the Sun was highest in the sky. The word solstice means “Sun standstill”. All through winter and spring the Sun has been moving northward in the sky at local noon. This has slowed down and tomorrow it will stop. After that it will begin to descend in the South at local noon until the winter solstice on December 21st.

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

Solstices
Comparing the sun’s path in the sky at the summer and winter solstices for the Grand Traverse Region. This is a stereographic representation of the whole sky which distorts the sky and magnifies the size of the sun’s path near the horizon.
Categories: Ephemeris Program, Seasons, Summer Solstice

06/19/2023 – Ephemeris – Juneteenth and the flight to freedom

June 19, 2023 Comments off

This is Bob Moler with Ephemeris for Juneteenth, Monday, June 19th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:56. The Moon, 1 day past new, will set at 11:22 this evening.

In 1865, it was on June 19th that the Union soldiers, led by Major General Gordon Granger, landed at Galveston, Texas with news that the war had ended and that the slaves were now free. Until then about the only path to freedom for the slaves was “To follow the Drinking Gourd”, or the Big Dipper, northward. The Big Dipper and the Great Bear, Ursa Major, has, for the last few millennia been the constellation of the north, being closer to the North Pole of the sky than it is now. The Earth’s axis has a slow wobble, called precession, caused by the gravitational pull of the Moon and Sun on Earth’s slight equatorial bulge of 30 miles wider than the pole to pole distance. That wobble period is nearly 26 thousand years.

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 path of the north pole of the sky (celestial sphere) over time. The celestial north pole is still approaching Polaris. In the past the Big Dipper was closer to the north pole of the sky than it is now. Polaris will be it closest to the north pole around the year 2110. Source: taichifuture.com/cosmology.html.
Runaway slaves following the Drinking Gourd
“Follow the Drinking Gourd,” a show at the Virginia Living Museum’s Abbit Planetarium based on Jeanette Winter’s children’s book of the same name, tells the story of a slave family who used the stars to make their way north. Visitors can watch the free show Saturdays in February. (Courtesy of Virginia Living Museum) Via Daily Press, Newport News, VA.
Categories: Constellations, History, Holiday Tags: , , , ,