Archive

Archive for the ‘Ephemeris Program’ Category

07/07/223 – Ephemeris – GTAS meeting and presentation: Observing the summer skies with the naked-eye

July 7, 2023 Comments off

This is Ephemeris for Friday, July 7th. Today the Sun will be up for 15 hours and 25 minutes, setting at 9:30, and it will rise tomorrow at 6:05. The Moon, 2 days before last quarter, will rise at 12:38 tomorrow morning.

Viewing Summer skies with just your Eyes will be the presentation by Robert Carroll at tonight’s meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers Observatory at 9 pm. Bob is one of the charter members of the society. He will show artist’s interpretation of the heavens. Then, focusing on Hercules, the Summer Triangle, and the Milky Way. Hopefully, he “will inspire young parents, and their children, to go OUTSIDE, leave the screens and tablets behind, and LOOK UP to see the night sky.” 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

The Milky Way from Cygnus to Scutum
The Milky Way from Cygnus to Scutum. In this image, actually a stack of 5 images, on August 12, 2018. I was hoping to record Perseid meteors. It was a poor showing, as non appeared in these images. We were hampered that year by smoke from the western US wildfires, which really affected the lower part of this image, which was still pretty high up in the sky. Featured here is the Great Rift, a series of dust clouds that split the Milky Way into two sections. Credit Bob Moler (me).
Categories: Ephemeris Program, GTAS Outreach Event Tags: , , ,

07/06/2023 – Ephemeris – Today the Earth is farther from the Sun than anytime this year

July 6, 2023 3 comments

This is Ephemeris for Thursday, July 6th. Today the Sun will be up for 15 hours and 26 minutes, setting at 9:30, and it will rise tomorrow at 6:04. The Moon, halfway from full to last quarter, will rise at 12:16 tomorrow morning.

Today, the Sun is at its farthest distance from the Earth. It’s called aphelion. The exact time actually occurred at 4:59 this morning at a distance of 94 and a half million miles away. Because of the gravitational pull of the Moon and planets on the Earth, especially Jupiter and Venus and gravitational pull of the planets, especially Jupiter on the Sun, the aphelion and perihelion, the closest date in January don’t occur on the same date or same distance every year. The date wanders by a day or two each year. The entire distance variation of the Earth from the Sun is plus or minus 1.5 million miles (2.4 million kilometers) over the year, makes summer the longest season by a few days because the Earth moves slower when farther from the Sun, than when it is nearer.

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.

Earth’s perihelion and aphelion and seasons are seen in this exaggerated diagram. The angles between the equinoxes and solstices are 90 degrees. The Earth’s distance from the Sun is 93 million miles, plus or minus 1.5 million miles. Click on the image to enlarge it. Credit: Gothika/Duoduoduo/Wikimedia commons 3.0 license.

Note: Apoapsis and Periapsis are generic terms for the farthest and nearest points in an orbit to the central body. For a body orbiting the Sun, it’s aphelion and perihelion. For a satellite of the Earth, it’s apogee and perigee.

Categories: Concepts, Earth, Ephemeris Program, Seasons, Sun Tags:

07/05/2023 – Ephemeris – Let’s find out where the naked-eye planets have wandered off to this week

July 5, 2023 Comments off

This is Ephemeris for Wednesday, July 5th. Today the Sun will be up for 15 hours and 27 minutes, setting at 9:31, and it will rise tomorrow at 6:04. The Moon, 2 days past full, will rise at 11:49 this evening.

Let’s find out where the naked-eye planets have wandered off to this week. Venus is our blazing Evening Star, seen low in the west most of the evening. It sets tonight at 11:28 pm, and by three minutes earlier each night. The red planet Mars is seen left of and above Venus. And left of Mars is the brighter star Regulus in Leo the lion. Venus is pulling away from Mars now. Mars is much fainter than Venus and difficult to spot in twilight. Saturn will rise shortly after midnight. And by 5:15 am will appear in the south, the brightest “star” in that direction. It will appear above and left of the waning gibbous Moon at that hour. Jupiter will be in the east at that hour. It 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 10:15 pm EDT, or about 45 minutes after sunset, tonight July 5, 2023. Created using Stellarium.
Jupiter, Saturn and the waning gibbous Moon seen at 5:15 am, about an hour before sunrise tomorrow morning, July 6, 2023. Fomalhaut, the loneliest star in the sky, is also visible. It’s kept company by Saturn for a few years every 30 years. Click or tap on the image to enlarge it. Created using Stellarium.
Waning gibbous Moon with labels as it might be seen at 5:15 am, about one hour before sunrise tomorrow, July 5, 2023. Created using Stellarium, LibreOffice Draw, and GIMP.
Telescopic Venus, Saturn and Jupiter (north up) as they would be seen in a small telescope, with the same magnification at 10:15 pm July 5, 2023, for Venus and 5:15 am July 6, 2023, for Jupiter and Saturn. Apparent diameters: Venus 36.21″ and is 28.1% illuminated; Saturn 18.18″, its rings 42.35″; Jupiter 37.04″. Mars, too small to be represented here, is 4.18″ in diameter. Venus, Saturn and Jupiter are approaching us, so their apparent diameters are growing. Europa is transiting in front of Jupiter. Normally it would not be visible. 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 July 5, 2023. The night ends on the left with sunrise on the 6th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.

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

07/04/2023 – Ephemeris – The Bicentennial space mission

July 4, 2023 Comments off

This is Bob Moler with Ephemeris for Independence Day, Tuesday, July 4th. 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, 1 day past full, will rise at 11:14 this evening.

To celebrate our nation’s 200th birthday, NASA attempted to land the Viking 1 lander on the planet Mars on July 4th, 1976. The Viking was a combination orbiter and lander and had a twin spacecraft arriving almost two months later. Viking 1 entered orbit on June 19th and began to survey the prime landing area, that radar from the Earth suggested would be smooth, to land on the day of the Bicentennial. However, images from orbit showed too many obstructions, so another area was surveyed. The mission planners from JPL found a spot and sent the Viking lander down to land on Mars on another historic date, July 20, 1976, the 7th anniversary of the Apollo 11 landing on the Moon.

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

Model of the Viking lander
Model of the Viking lander. Credit NASA/JPL.
July 20, 1976
First image sent back from Viking 1 after landing on Mars, July 20, 1976. Credit: NASA/JPL.

NASA did finally make a historic landing on July 4th,

the Mars Pathfinder mission, with the first rover to operate on Mars, the Sojourner rover, landed on July 4, 1997. It was a microwave sized rover. The mission on the surface lasted 85 days.

Pathfinder_collage
Pathfinder collage, Left to right, the collapsed Sojourner rover attached to one of the lander’s tetrahedron petals; 24 inflated airbags, attached 6 to a side of the Pathfinder tetrahedron; launch of the Delta II rocket carrying Pathfinder to Mars. Credit NASA/JPL.
Sojourner rover investigates Yogi
Sojourner rover investigates a rock named Yogi with its Alpha Particle X-ray Spectrometer to determine its composition. Credit NASA/JPL.
Pathfinder Lander from Sojourner
The Pathfinder Lander/Base Station and its deflated airbags from Sojourner. All communication from Sojourner to Earth was relayed through the Base Station. Credit NASA/JPL.
Categories: Ephemeris Program, History, Mars, NASA Tags: , , , , ,

07/03/2023 – Ephemeris – The Sun is more massive than most stars

July 3, 2023 Comments off

This is Bob Moler with Ephemeris for Monday, July 3rd. 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, at full today, will rise at 10:28 this evening.

The Sun appears to be a singular object in the sky. There is none other. But is that true? No, it’s not. The Sun is a star, middle-aged for a star of its mass. The Sun is bigger than most stars, because most stars are runty red dwarf stars. In fact the closest star to our Sun is a red dwarf, called Proxima Centauri, the third, outlying star in the triple star system whose brightest star is called Rigil Kentaurus, though better known by its 1603 Bayer catalog designation, Alpha Centauri. Proxima is a challenge to spot even with binoculars. It turns out that stars visible to the naked eye are all brighter than the Sun. As far as the range of stellar masses go, the Sun is pretty much in the middle. Rigil Kentaurus itself is 8 percent more massive than the Sun and 50 percent brighter. Both Rigil Kentaurus and Proxima are too far south to see from Michigan.

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 Hertzsprung-Russell Diagram showing the stars by luminosity (actual brightness) and surface temperature. There are a lot more stars at the bottom of the main sequence (Stars that create helium from hydrogen to produce energy) than anywhere above them. Credit NASA/Chandra with an addition by the author.
Categories: Ephemeris Program, Stars Tags: , , , ,

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: ,