Archive

Archive for the ‘Ephemeris Program’ Category

Ephemeris: 07/09/2024 – The Moon Tonight – Mare Crisium

July 9, 2024 Comments off

This is Ephemeris for Tuesday, July 9th. Today the Sun will be up for 15 hours and 22 minutes, setting at 9:29, and it will rise tomorrow at 6:07. The Moon, halfway from new to first quarter, will set at 11:53 this evening.

Tonight’s four-day old crescent Moon will be seen in the west at about 10:30 PM, though it’s visible much earlier than that. Binoculars will show a small gray round area near the right edge of the Moon which is seen in the full moon as the eye of the Man in the Moon. The feature is called Mare Crisium or the Sea of Crises. And is an Oval 385 by 354 miles in extent. However, it is elongated east to west rather than what it appears to be, north to south. That is due to foreshortening because it is near the limb of the Moon and thus curved away from us. So we are looking at it at an oblique angle. Mare Crisium is thought to be the result of an impact of an asteroid that occurred nearly 4 billion years ago during the Late Heavy Bombardment.

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 four day old Moon
The four day old Moon as it might be seen in binoculars or small telescope tonight, July 9th 2024. I’m highlighting Mare Crisium that lies near the limb of the Moon from Earth’s vantage point. Compare it with the images below taken from the Apollo 11 spacecraft and another one looking at the Moon from Earth’s side at the same phase as the Apollo 11 photograph. Created using Stellarium, LibreOffice Draw, and GIMP.
Mare Crisium from the side of the Moon taken by the Apollo 11 crew
Mare Crisium from the side of the Moon taken by the Apollo 11 crew as they departed the Moon, showing its true shape. Credit: NASA/Apollo 11 Crew.
The nearly first quarter Moon as seen from the Earth
The nearly first quarter Moon as seen from the Earth at the same scale and phase as the Apollo picture above. See if you can match the maria or seas to the Apollo 11 picture . Created using stellarium.
Categories: Ephemeris Program, The Moon Tags: ,

Ephemeris: 07/08/2024 – The Summer Triangle dominates the eastern sky

July 8, 2024 Comments off

This is Ephemeris for Monday, July 8th. Today the Sun will be up for 15 hours and 23 minutes, setting at 9:29, and it will rise tomorrow at 6:06. The Moon, 3 days past new, will set at 11:34 this evening.

We’re two weeks into summer, and the asterism or informal constellation called the Summer Triangle can be seen in the eastern sky as it gets dark. The highest of the three bright stars is Vega in the constellation Lyra the harp, whose body is seen in a narrow parallelogram just below it. The second star of the triangle is Deneb, in Cygnus the swan, lower and left of Vega, It appears dimmer than Vega because it is by far the most distant of the three. The third star of the Summer Triangle is seen farther below and a right of Vega. It is Altair in Aquila the eagle, and the closest. Altair is 16.5 light years away, Vega is 27 light years, while Deneb may be a whopping 2,600 light years away. One light year by the way, is 6 trillion miles (9 trillion kilometers).

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

Finder animation for the Summer Triangle
Finder animation for the Summer Triangle. Created using Stellarium and GIMP.
The Milky Way in the Summer Triangle
Something that we are going to be missing in the next couple of weeks with the Moon being out in the evening will be the Milky Way that runs through the Summer Triangle. This photograph by Daniel Dell’Olmo emphasizes the Milky Way that can be seen under moonless skies.
Categories: Asterism, Ephemeris Program, Observing, Stars

Ephemeris: 07/05/2024 – GTAS meeting: processing astrophotographs

July 5, 2024 Comments off

This is Ephemeris for Friday, July 5th. 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 is new today, and won’t be visible.

Tonight’s meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers observatory, which starts at 9 PM tonight, will feature a talk by Dan Dall’Olmo, one of our successful astrophotographers in the society. He will discuss image processing. Taking the picture is only the beginning. He will show how to bring out and sharpen images taken with digital cameras. Back in my day processing photographs involved chemicals in the darkroom. “I love the smell of Hypo in the morning”. Now it involves computers and software. Afterward if it’s, clear we’ll be viewing the sky. Note the later start time for the meeting. We follow the later sunsets this time of year, so viewing starts after sunset. The observatory is located south of Traverse City on Birmley Rd. Between Garfield and Keystone roads.

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

Here are a couple of Dan’s photographs of celestial objects visible this time of year. The eaw images do not look this good, hence the image processing to bring out the image brightness and detail.

Trifid Nebula
Messier 20 or M20 the Trifid Nebula in Sagittarius. Click or tap on the image to enlarge it. Credit Dan Dall’Olmo.
The Summer Triangle and the Milky Way
The Summer Triangle of the three brightest stars in this image, as if it was overheaad and one is facing south.. At the top is Deneb in Cygnus the swan, who’s other stars are overpowered by the Milky Way. Just to the left of Deneb is the North American Nebula in red. On the left is Vega in Lyra the harp. Its parallelogram of stars can seen below it. At the bottom is Altair in Aquila the eagle which is flanked by two stars. Crossing through the Summer Triangle is the Milky Way with the dark clouds of the Great Rift bisecting it. Click or tap on the image to enlarge it. Credit Dan Dall’Olmo.
Categories: Ephemeris Program, GTAS Outreach Event, Star Party Tags: , , ,

Ephemeris: 07/04/2024 – The Earth at aphelion

July 4, 2024 Comments off

This is Ephemeris for Independence Day, Thursday, July 4th. Today the Sun will be up for 15 hours and 27 minutes, setting at 9:31, and it will rise tomorrow at 6:03. The Moon, 1 day before new, will rise at 5:10 tomorrow morning.

Tomorrow morning at 1:59 AM , actually overnight tonight, the Earth will reach aphelion from the Sun, the farthest it gets from it during the year. Earth will be 94 and a half million miles away from the Sun, a bit farther than our normal 93 million. In a planet’s orbit of the Sun, the Earth is no exception, it moves slowest when farthest from the Sun than when it’s nearest. It doesn’t make much difference in the amount of heat we get from the Sun being only 1 1/2% farther than average. But it makes summer the longest season at 94 days, versus winter’s 89 days. OK, I know it doesn’t feel like it here in Northern Michigan, but count the days between each solstice and the next equinox.

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

A highly exaggerated look at the orbit of the Earth showing perihelion and aphelion, also the equinoxes and solstices and the relation thereof. Periapsis and apoapsis are general terms, for any orbit. For a satellite orbiting the Earth the terms would be perigee and apogee. Source unknown.
This is a diagram of the true shape of the Earth’s orbit and position of the Sun showing aphelion and perihelion for the year 2024. The dates do vary by up to couple of days each year as do the distances a little bit. The date difference is a bit more than the date change of the solstices and equinoxes year to year. Created using my LookingUp app, LibreOffice Draw for captions, and GIMP.

Categories: Astronomical Event, Earth, Ephemeris Program, Sun Tags:

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: 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:

Ephemeris: 06/28/2024 – Solar viewing at Sleeping Bear Dunes tomorrow

June 28, 2024 Comments off

This is Ephemeris for Friday, June 28th. 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, at last quarter today, will rise at 1:37 tomorrow morning.

Tomorrow, Saturday, June 29th there will be solar viewing at the Sleeping Bear Dunes National Lakeshore, at the Dune Climb from 3 to 6 PM. Park Rangers will be joined by members of the Grand Traverse Astronomical Society with their specially filtered telescopes to view the Sun safely. This is a period of great solar activity. Remember the Aurora Borealis of a few weeks ago. Solar filtered telescopes will safely view the surface of the sun, called the photosphere and sunspots, while the society also has two special solar telescopes with which to view the layer of gas above the surface called the chromosphere and prominences which look like flames coming off the chromosphere. This is one of two solar observing opportunities this summer.

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 white light Sun
The white light Sun as of Thursday gives us a preview of what it will look like on Saturday. Most solar telescopes we use will give a mirror image. The sunspots will move and change from Thursday’s appearance, seen here. White light filters generally give the Sun an orange hue. It’s really white. Credit: NASA/Solar Dynamics Observatory.
The Sun in the light of hydrogen
The Sun in the light of hydrogen taken late Thursday our time (11:16 pm). The color is truly red in this photograph and in our hydrogen alpha solar telescopes. The alpha radiation of hydrogen is in the red part of the spectrum. What we are looking at is the chromosphere was a which is a layer of gas above the photosphere, which is the bright ball of the Sun that we see through white light telescopes. It gives us a very different view of the Sun which is much less smooth and with a lot of detail. The dark clouds over the photosphere are called filaments and if they were at the edge of the Sun we’d see them as bright features called prominences, though dimmer than the chromosphere which is why they appear dark when silhouetted over the chromosphere. The bright areas are called pledges and are magnetically active areas as are the sunspots. These are areas which may produce sunspots later. The chromosphere changes a lot more than the white light Sun and its sunspots. Credit: NISP / Learmouth, Australia.

Categories: Ephemeris Program, GTAS Outreach Event, Observing, Sun Tags: , ,

Ephemeris: 06/27/2024 – Why do astronomers think a nova will appear this year?

June 27, 2024 Comments off

This is Ephemeris for Thursday, 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 before last quarter, will rise at 1:18 tomorrow morning.

Our expected nova this year, T Coronae Borealis, is expected by some astronomers to erupt sometime in September give or take, but nobody knows for sure. The last eruption was seen in 1946. And if the average time between outbursts is 80 years, it seems to be two years early this time. In 1946 there were observations showing that there were some precursor effects going on before the eruption, and those have been noticed this time too, which is which why we assume that the nova will occur this year. Stars that vary in brightness are denoted in a constellation by a letter starting with R through Z, then RR, RS, etcetera through ZZ. After that it’s V and a number plus the constellation name or abbreviation.

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

T Coronae Borealis Finder Chart
This animated GIF shows the constellations of Hercules, Corona Borealis and Boötes from left to right. Flashing on and off is T Coronae Borealis (T CrB). It is shown at its approximate maximum brightness, about the same as Alphecca (spelled Alphekka here). Created using Stellarium and GIMP.
Categories: Ephemeris Program, Nova, Observing Tags: , ,

Ephemeris: 06/26/2024 – Where are the naked-eye planets this week?

June 26, 2024 Comments off

This is Bob Moler with Ephemeris for Wednesday, 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, 2 days before last quarter, will rise at 12:58 tomorrow morning.

Let’s find out where the naked-eye planets have wandered off to this week. Venus and Mercury are too close to the direction of the Sun to be seen. Both are on the evening side of the Sun, but lost in its glare. 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 southeast just above and left of the Moon, and Mars will be lower in the east, and Jupiter will be very low in the east-northeast. 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 1:15 am, Mars at 3:07 am, and Jupiter at 4:19 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

The Moon as it might appear in binoculars or a small telescope at 5 AM tomorrow morning, June 27th 2024. Selected features are labeled. Created using Stellarium, LibreOffice Draw, and GIMP.
The Moon, Saturn, Mars and Jupiter as they might be seen low in the east and southeastern sky at 5:15 AM, or about 45 minutes before sunrise, tomorrow morning June 27, 2024. Saturn will rise at 1:03 AM, Mars at 2:59 AM, and Jupiter at 4:09 AM. Click or tap on the image to enlarge it. Created using Stellarium.
Telescopic Saturn and Jupiter (north up) as they would be seen in a small telescope at 5 AM June 27th 2024 with the same magnification. Apparent diameters: Saturn 17.8″, its rings 41.4″; Mars, too small to be represented here, is 5.3″; Jupiter 33.5″. 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 June 26, 2023. The night ends on the left with sunrise on the 27th. 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, June 26th and 27th 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. 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: 06/25/2024 – Three kinds of novas

June 25, 2024 Comments off

This is Ephemeris for Tuesday, June 25th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 3 days before last quarter, will rise at 12:35 tomorrow morning.

As I mentioned yesterday we’re expecting a nova or bright star that we expect to appear sometime this year, maybe in September according to some astronomers. A nova is a rapid brightening of a star due to some cataclysmic event happening to it. There are three kinds that we actually know of. A nova, which is what we’re expecting; a supernova, an explosion maybe a million times greater; and the recently discovered kilonova when two neutron stars collide, which is a thousand or so times brighter than an ordinary nova. A nova and one kind of supernova (Type 1) involve a binary star system which contains a white dwarf star near the end of its life close enough to a larger star to siphon off material. At some point enough has built up and an explosion occurs.

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 second type of Supernova is caused when a supermassive star’s core collapses when it’s made of iron and tries to fuse it into heaver elements. That process takes energy rather than producing it. Oops! The star collapses on itself, and… Kablooey!

Nova in a binary system


A red giant star and white dwarf orbit each other in this animation of a nova similar to T Coronae Borealis. The red giant is a large sphere in shades of red, orange, and white, with the side facing the white dwarf the lightest shades. The white dwarf is hidden in a bright glow of white and yellows, which represent an accretion disk around the star. A stream of material, shown as a diffuse cloud of red, flows from the red giant to the white dwarf. When the red giant moves behind the white dwarf, a nova explosion on the white dwarf ignites, creating a ball of ejected nova material shown in pale orange. After the fog of material clears, a small white spot remains, indicating that the white dwarf has survived the explosion. NASA/Goddard Space Flight Center.

Categories: Concepts, Ephemeris Program, Nova Tags: ,