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Ephemeris: 09/06/2023 – Let’s find out where the naked-eye planets and comet Nishimura have wandered off to

September 6, 2023 Comments off

This is Ephemeris for Wednesday, September 6th. Today the Sun will be up for 12 hours and 59 minutes, setting at 8:10, and it will rise tomorrow at 7:12. The Moon, at last quarter today, will rise at 11:40 this evening.

Let’s find out where the naked-eye planets have wandered off to. Three of those five planets are now visible but Mars and Mercury are too close to the Sun to be seen. Saturn is the sole evening planet visible. Jupiter and Venus are officially the only visible morning planets. Saturn can be spotted in the southeast in the evening. And it will still be visible throughout the morning hours morning until twilight starts. Saturn is in retrograde or westward motion against the stars of Aquarius. Jupiter will rise at 10:54pm. It is slowing its eastward motion and will become stationary tomorrow. Venus is our brilliant morning star. It will rise at 4:43 tomorrow morning. Comet Nishimura is left and a bit below Venus in the east-northeast.

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

Saturn, at 10 pm tonight
Saturn, at 10 pm tonight, September 6, 2023, and the zodiacal constellations, from left to right, part of Pisces, Aquarius and Capricornus. Click or tap on the image to enlarge it. Created using Stellarium and GIMP.
Morning planets and winter stars
Morning planets and winter stars. Click or tap on the image to enlarge it. Created using Stellarium and GIMP.
The Moon as it might appear at 6 am, tomorrow, September 7, 2023, about 12 hours after being at the last quarter phase, with selected features labeled. If you want to know where Hell is, I found it. The crater commemorates an 18th century Hungarian Jesuit priest and astronomer Maximilian Hell.
Telescopic Saturn, Jupiter and Venus (north up) as they would be seen in a small telescope, with the same magnification at 10 pm September 6, 2023, for Saturn and midnight September 7, 2023, for Jupiter and 6 am September 7, 2023, for Venus. Apparent diameters: Saturn 18.93″, its rings 44.10″; Jupiter 44.78″; and Venus 45.46″ and is 16.9% illuminated. 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
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on September 6, 2023. The night ends on the left with sunrise on the 7th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
Comet C/2023 P1 (Nishimura) at 6:00 am September 7, 2023, from Traverse City, MI, US. This is 1 hour 12 minutes before sunrise. Click or tap image to enlarge it. Created using Stellarium.
Categories: Comet, Ephemeris Program, Observing, Planets Tags: , , , , , ,

Ephemeris: 09/05/2023 – Where is Comet Nishimura tomorrow morning the 6th

September 5, 2023 Comments off

This is Bob Moler with Ephemeris for Tuesday, September 5th. Today the Sun will be up for 13 hours and 2 minutes, setting at 8:12, and it will rise tomorrow at 7:10. The Moon, 1 day before last quarter, will rise at 11:03 this evening.

Comet Nishimura is supposedly a very dim naked-eye comet now, best found and seen in binoculars, though it will get brighter in the next few days. On Ephemeris, when I talk about things that one can observe, it must be bright enough to be spotted with the naked eye, even though it may be best appreciated with binoculars or telescope. This comet is a little dubious in that regard. Comets, to my eyes at least, appear dimmer than what their magnitudes suggest. More specific information is on my blog at bobmoler.wordpress.com, an Ephemeris Extra post for August 31st. Tomorrow morning the comet is to the left of Venus in the east northeast. Comet Nishimura will be visible for our location through next Monday.

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

Comet C/2023 P1 (Nishimura) at 6:00 am September 6, 2023 from Traverse City, MI, US. This is 1 hour 10 minutes before sunrise. Click or tap image to enlarge it. Created using Stellarium.
Categories: Comet, Ephemeris Program, Observing Tags:

Ephemeris: 09/04/2023 – One more look at Saturn’s Rings

September 4, 2023 Comments off

This is Bob Moler with Ephemeris for Labor Day, Monday, September 4th. Today the Sun will be up for 13 hours and 5 minutes, setting at 8:14, and it will rise tomorrow at 7:09. The Moon, 2 days before last quarter, will rise at 10:32 this evening.

We are going to take one more look at Saturn’s rings, and these are the rings which are not visible from the Earth, but only from spacecraft in the vicinity of Saturn. We have the A, B and C rings which are visible from here Then there’s a D ring inside the C ring. There’s the F ring, a very thin ring which is controlled by a tiny moon called Prometheus, just outside the A ring. Farther out there’s an E ring which is a very diffuse ring, in the orbit of the moon Enceladus, which is an active satellite. It has geysers at the at its South Pole which vent water ice and organic compounds, which form the E ring. Saturn has many more rings and ring arcs in orbit around it, too numerous to mention here.

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 day the Earth smiled" image from Cassini
“The day the Earth smiled” image from the Cassini spacecraft. The spacecraft, at that time was behind Saturn, in its shadow, performing an eclipse of the Sun. The rings are seen from their unlit side. The bright areas in the rings are due to forward scattering of very small particles, like seeing dust in a sun beam. The innermost D and C rings are made of those small particles. The B ring is made-up of larger particles, more densely packed, so in this image it turns out to be black. Next out is the A ring, and the skinny ring on the outside of the A ring is the F ring. Farther out through the very faint the G ring. And the outermost is the E ring caused by the geysers from the moon Enceladus, which can be seen near the inner edge on the left side of the ring. Other than the A, B and C rings the other rings were lettered in order of their discovery, which is why they’re out of order physically. The image has to be enlarged to spot the Earth and all it’s smiling earthlings, packed into one pixel. The Earth is seen at 4 o’clock from Saturn, just outside the G ring. There is a better enlargement below. Tap or click on the image to enlarge it. Credit: NASA/JPL/Cassini/Carolyn Porco.

Off-topic

The Earth and above it, the Moon from the image above. Credit: NASA/JPL/Cassini/Carolyn Porco.
Categories: Ephemeris Program Tags:

Ephemeris: 09/01/2023 – GTAS meeting tonight – Dr. Jerry Dobek goes over to the dark side

September 1, 2023 1 comment

This is Ephemeris for Friday, September 1st. Today the Sun will be up for 13 hours and 14 minutes, setting at 8:19, and it will rise tomorrow at 7:06. The Moon, 2 days past full, will rise at 9:24 this evening.

Tonight at 8 p.m. at the meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers Observatory, and on Zoom. Observatory Director Dr. Jerry Dobek will be giving a talk on what he calls dark material. This is from a new book he collaborated on: The Barnard Objects – Then and Now, a look at dark nebulae, comparing E. E. Barnard’s Black and White photographic plates to modern color digital photography. Dark nebulae are clouds of gas and dust seen in the summer Milky Way. After the meeting, at 9 p.m. the society will host a star party to view a rather bright night sky including Saturn. The observatory is located south of Traverse City on Birmley Road between Garfield and Keystone roads. Zoom instructions will be at gtastro (dot) org.

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 book cover of The Barnard Objects Then and Now, which came out in July.
Categories: Ephemeris Program, GTAS Outreach Event Tags:

Ephemeris: 08/31/2023 – Looking ahead to September’s skies

August 31, 2023 Comments off

This is Ephemeris for Thursday, August 31st. Today the Sun will be up for 13 hours and 17 minutes, setting at 8:21, and it will rise tomorrow at 7:04. The Moon, 1 day past full, will rise at 9:02 this evening.

Let’s look at the skies of September which starts tomorrow. The Sun will be moving at its greatest speed in its retreat to the south. Daylight hours in the Interlochen/Traverse City area will drop from 13 hours and 14 minutes tomorrow to 11 hours 46 minutes on the 30th. The altitude of the Sun above the southern horizon at local noon will be 53 degrees tomorrow, and will descend to 42 degrees on the 30th. The Straits* area will see the Sun a degree lower. The season of summer is getting short, so enjoy it while you can. Summer ends and fall begins at 12:50 a.m. on the 23rd, the autumnal equinox. Venus is our brilliant Morning Star now, And on the 29th we’ll have the Harvest Moon, the nearest full moon to the autumnal equinox. There is a comet approaching the Sun in the first half of September, It will be described in an Ephemeris Extra later today.

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.

*For those not familiar with our area the Straits refer to the Straits of Mackinac (pronounced Mackinaw) that separate the Upper and Lower Peninsulas of Michigan.

Addendum

September Evening Star Chart

Star Chart for September 2023. Click or tap on the image to enlarge it. Created using my LookingUp program.

The planets and stars are plotted for the 15th at 10 p.m. EDT in the evening and 6 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian, West 75° longitude. (An hour 45 minutes behind our daylight saving time meridian during EDT). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes earlier than the current time.

September Morning Star Chart

Star Chart for September 2023 (6 am EDT, September 15, 2022). Click on the image to enlarge it. Created using my LookingUp program.

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.
  • The Summer Triangle is in red.

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning Twilight Evening Twilight Dark Night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2023-09-01 5h26m 6h04m 21h29m 22h08m – – 0.93
2023-09-02 5h27m 6h05m 21h27m 22h05m – – 0.86
2023-09-03 5h29m 6h07m 21h25m 22h03m 22h03m 22h07m 0.78
2023-09-04 5h30m 6h08m 21h23m 22h01m 22h01m 22h33m 0.68
2023-09-05 5h32m 6h09m 21h21m 21h59m 21h59m 23h03m 0.57
2023-09-06 5h34m 6h11m 21h19m 21h56m 21h56m 23h41m 0.47
2023-09-07 5h35m 6h12m 21h17m 21h54m 21h54m – 0.37
2023-09-08 5h37m 6h13m 21h15m 21h52m 21h52m 0h27m 0.28
2023-09-09 5h38m 6h15m 21h13m 21h50m 21h50m 1h21m 0.20
2023-09-10 5h40m 6h16m 21h11m 21h48m 21h48m 2h22m 0.13
2023-09-11 5h41m 6h17m 21h09m 21h46m 21h46m 3h27m 0.07
2023-09-12 5h42m 6h19m 21h07m 21h43m 21h43m 4h32m 0.03
2023-09-13 5h44m 6h20m 21h05m 21h41m 21h41m 5h38m 0.01
2023-09-14 5h45m 6h21m 21h03m 21h39m 21h39m 5h45m 0.00
2023-09-15 5h47m 6h23m 21h01m 21h37m 21h37m 5h47m 0.01
2023-09-16 5h48m 6h24m 20h59m 21h35m 21h35m 5h48m 0.04
2023-09-17 5h50m 6h25m 20h57m 21h33m 21h33m 5h50m 0.09
2023-09-18 5h51m 6h27m 20h55m 21h31m 21h31m 5h51m 0.16
2023-09-19 5h52m 6h28m 20h53m 21h28m 21h39m 5h52m 0.24
2023-09-20 5h54m 6h29m 20h51m 21h26m 22h10m 5h54m 0.33
2023-09-21 5h55m 6h30m 20h49m 21h24m 22h52m 5h55m 0.44
2023-09-22 5h57m 6h32m 20h47m 21h22m 23h46m 5h57m 0.55
2023-09-23 5h58m 6h33m 20h45m 21h20m – 5h58m 0.66
2023-09-24 5h59m 6h34m 20h43m 21h18m 0h53m 5h59m 0.76
2023-09-25 6h01m 6h35m 20h41m 21h16m 2h11m 6h01m 0.85
2023-09-26 6h02m 6h37m 20h39m 21h14m 3h35m 6h02m 0.93
2023-09-27 6h03m 6h38m 20h37m 21h12m 4h59m 6h03m 0.98
2023-09-28 6h05m 6h39m 20h36m 21h10m – – 1.00
2023-09-29 6h06m 6h40m 20h34m 21h08m – – 0.99
2023-09-30 6h07m 6h42m 20h32m 21h06m – – 0.96

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

Date         Time     Event
Sep  1  Fr            Venus: 27.4° W
     3  Su   3:44 am  Moon Ascending Node
     4  Mo   3:44 pm  Moon-Jupiter: 3.4° S
     5  Tu   3:25 pm  Moon-Pleiades: 1.3° N
     6  We   7:03 am  Mercury Inferior Conj.
     6  We   6:21 pm  Last Quarter
     8  Fr   9:18 am  Moon North Dec.: 28.2° N
     9  Sa  11:32 pm  Moon-Pollux: 1.7° N
    12  Tu  11:42 am  Moon Apogee: 406,300 km
    14  Th   9:40 pm  New Moon
    17  Su  11:12 am  Moon-Spica: 2.6° S
    17  Su   3:18 pm  Moon Descending Node
    19  Tu            Venus greatest brilliancy
    19  Tu   5:54 am  Neptune Opposition
    21  Th   3:50 am  Moon-Antares:  0.9° S
    22  Fr   8:59 am  Mercury Elongation: 17.9° W
                      Favorable greatest elongation for
                      the Northern Hemisphere.
    22  Fr   3:32 pm  First Quarter
    22  Fr  11:42 pm  Moon South Dec.: 28.3° S
    23  Sa   2:50 am  Autumnal Equinox
    26  Tu   9:25 pm  Moon-Saturn: 2.6° N
    27  We   9:05 pm  Moon Perigee: 359,900 km
    29  Fr   5:57 am  Full Harvest Moon
    30  Sa  12:49 pm  Moon Ascending Node
Oct  1  Su            Venus: 44.2° W

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

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.

Sun and Moon Rising and Setting Events

                Ephemeris of Sky Events for Interlochen/TC
September 2023    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Fri  1| 07:04a  08:19p  13:14 | 09:26p  05:58a |      Rise 09:24p   94%|
|Sat  2| 07:06a  08:18p  13:11 | 09:24p  05:59a |      Rise 09:45p   88%|
+------+-----------------------+----------------+-----------------------+
|Sun  3| 07:07a  08:16p  13:08 | 09:21p  06:01a |      Rise 10:07p   79%|
|Mon  4| 07:08a  08:14p  13:05 | 09:19p  06:02a |      Rise 10:32p   70%|
|Tue  5| 07:09a  08:12p  13:02 | 09:17p  06:03a |      Rise 11:03p   60%|
|Wed  6| 07:10a  08:10p  12:59 | 09:15p  06:05a |L Qtr Rise 11:40p   49%|
|Thu  7| 07:12a  08:08p  12:56 | 09:13p  06:06a |      Rise 12:26a   39%|
|Fri  8| 07:13a  08:06p  12:53 | 09:11p  06:08a |      Rise 01:20a   30%|
|Sat  9| 07:14a  08:05p  12:50 | 09:09p  06:09a |      Rise 02:21a   22%|
+------+-----------------------+----------------+-----------------------+
|Sun 10| 07:15a  08:03p  12:47 | 09:07p  06:10a |      Rise 03:26a   14%|
|Mon 11| 07:16a  08:01p  12:44 | 09:05p  06:12a |      Rise 04:32a    8%|
|Tue 12| 07:17a  07:59p  12:41 | 09:03p  06:13a |      Rise 05:37a    4%|
|Wed 13| 07:19a  07:57p  12:38 | 09:01p  06:14a |      Rise 06:41a    1%|
|Thu 14| 07:20a  07:55p  12:35 | 08:59p  06:15a |New   Set  08:04p    0%|
|Fri 15| 07:21a  07:53p  12:32 | 08:57p  06:17a |      Set  08:20p    1%|
|Sat 16| 07:22a  07:51p  12:29 | 08:55p  06:18a |      Set  08:36p    3%|
+------+-----------------------+----------------+-----------------------+
|Sun 17| 07:23a  07:50p  12:26 | 08:53p  06:19a |      Set  08:54p    8%|
|Mon 18| 07:24a  07:48p  12:23 | 08:51p  06:21a |      Set  09:14p   14%|
|Tue 19| 07:26a  07:46p  12:20 | 08:49p  06:22a |      Set  09:39p   22%|
|Wed 20| 07:27a  07:44p  12:17 | 08:47p  06:23a |      Set  10:10p   31%|
|Thu 21| 07:28a  07:42p  12:13 | 08:45p  06:24a |      Set  10:51p   41%|
|Fri 22| 07:29a  07:40p  12:10 | 08:43p  06:26a |F Qtr Set  11:45p   52%|
|Sat 23| 07:30a  07:38p  12:07 | 08:41p  06:27a |      Set  12:52a   63%|
+------+-----------------------+----------------+-----------------------+
|Sun 24| 07:32a  07:36p  12:04 | 08:39p  06:28a |      Set  02:11a   74%|
|Mon 25| 07:33a  07:34p  12:01 | 08:38p  06:30a |      Set  03:34a   84%|
|Tue 26| 07:34a  07:33p  11:58 | 08:36p  06:31a |      Set  04:59a   91%|
|Wed 27| 07:35a  07:31p  11:55 | 08:34p  06:32a |      Set  06:22a   97%|
|Thu 28| 07:36a  07:29p  11:52 | 08:32p  06:33a |      Set  07:43a  100%|
|Fri 29| 07:38a  07:27p  11:49 | 08:30p  06:35a |Full  Rise 07:45p   99%|
|Sat 30| 07:39a  07:25p  11:46 | 08:28p  06:36a |      Rise 08:07p   96%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

Categories: Ephemeris Program, Month preview, Observing Tags:

Ephemeris: 08/30/2023 – Let’s find out where the naked-eye planets are

August 30, 2023 Comments off

This is Ephemeris for Wednesday, August 30th. Today the Sun will be up for 13 hours and 20 minutes, setting at 8:23, and it will rise tomorrow at 7:03. The Moon, is the full Blue Moon today, and it will rise at 8:39 this evening. No, it’s not really blue in color. The Blue Moon is the second full moon in a particular month.

Let’s find out where the naked-eye planets are. Three of those five planets are now visible. Mars and Mercury are too close to the Sun to be seen. Saturn is the sole evening planet visible. Jupiter and Venus are officially the only visible morning planets. Saturn can be spotted in the southeast in the evening. And it will still be visible throughout the morning hours until just before sunrise. Tonight Saturn will appear above and right of the full moon, though it might be difficult to spot in the Moon’s glare. Saturn is in retrograde or westward motion now, against the stars of Aquarius. Jupiter will rise at 10:54pm. It is slowing its eastward motion and will become stationary on September 7th. Venus is making an appearance in the morning sky now as our brilliant morning star. It will rise at 5:13 tomorrow morning.

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 and Saturn at 10 pm EDT tonight, August 30, 2013. The relative positions, especially of Saturn, will change based on your time zone relative to Eastern Daylight Time (UT -4 hours). Created using Stellarium.
The full moon with selected features labeled, at 10 pm tonight, August 30, 2023. Created using Stellarium, LibreOffice Draw and GIMP.
Jupiter and Venus with the first magnitude stars of winter as they might be seen at 6:30 am, tomorrow morning, August 31, 2023. Created using Stellarium, LibreOffice Draw and GIMP.
Telescopic Saturn, Jupiter and Venus (north up) as they would be seen in a small telescope, with the same magnification at 10 pm August 30, 2023, for Saturn and 6:00 am August 31, 2023, for Jupiter and Venus. Apparent diameters: Saturn 18.96″, its rings 44.17″; Jupiter 43.86″; and Venus 50.31″ and is 10.6% illuminated. 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 August 30, 2023. The night ends on the left with sunrise on the 31st. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.

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

Ephemeris: 08/29/2023 – Saturn’s rings disappear every 15 years

August 29, 2023 Comments off

This is Ephemeris for Tuesday, August 29th. Today the Sun will be up for 13 hours and 23 minutes, setting at 8:25, and it will rise tomorrow at 7:02. The Moon, 1 day before full, will set at 6:05 tomorrow morning.

As seen in even low powered telescopes Saturn’s rings are visible. Currently, the rings are closing towards that edge on point which will they reach on March 23rd 2025 and then begin to open up again. The rings orbit Saturn’s equator, and Saturn has a nearly 27 degree inclination of its axis to its orbit, like the Earth’s 23 1/2 degrees and that means that near the equinoxes Saturn’s rings turn out to be nearly edge on to the Sun and the Earth, since we orbit much closer to the Sun than Saturn. Near the solstices on Saturn the rings are open to their widest extent. This occurs about 7 ½ years after the rings go edge on, and 7 ½ years before the next time. The next time the rings go edge on Saturn will be too close to the direction of the Sun to spot, but when they do go edge-on, they disappear. They are 150,000 miles in diameter and less than 70 feet thick.

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

Saturn's rings change.
How the appearance of the rings change as Saturn orbits the Sun. Credit: NASA Hubble Space Telescope.
Categories: Ephemeris Program, Observing, Saturn Tags:

Ephemeris: 08/28/2023 – Observing Saturn’s rings

August 28, 2023 Comments off

This is Ephemeris for Monday, August 28th. Today the Sun will be up for 13 hours and 26 minutes, setting at 8:26, and it will rise tomorrow at 7:01. The Moon, 2 days before full, will set at 4:38 tomorrow morning.

The most striking feature of the planet Saturn are its rings. It is not the only planet with rings. Jupiter Uranus and Neptune all have rings, plus some asteroids. And at least one Kuiper belt objects has rings, but Saturn has the grandest of all the ring systems. The broad rings are easily seen in small telescopes. They are labeled A, B and C, A being the outermost of the bright rings B is the center most and C is just barely seen inside the B ring. The diameter of these rings to the outside of the A ring is 150,000 miles, a bit more than the average distance from the Earth to our Moon, and a little less than 70 feet thick so when they go edge on to us as they do about every 15 or so years they completely disappear.

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

Saturn’s rings are much more complex than what can be seen in a small telescope. Observing Saturn through a small telescope, the A and B rings are evident, though the Cassini Division, of nearly 5,000 miles in width, may be elusive. The C, or Crêpe, ring is very hard to see, and is best seen as a dusky shadowlike feature against the planet. This image of Saturn was created by Stellarium, annotations were created in LibreOffice Draw, assembled and output using GIMP.

More on Saturn’s rings tomorrow.

Categories: Ephemeris Program, Observing, Saturn Tags: ,

Ephemeris: 08/25/2023 – Saturn will reach opposition on Sunday

August 25, 2023 Comments off

This is Ephemeris for Friday, August 25th. Today the Sun will be up for 13 hours and 35 minutes, setting at 8:32, and it will rise tomorrow at 6:57. The Moon, 1 day past first quarter, will set at 12:57 tomorrow morning.

The planet Saturn will reach opposition on Sunday. That means it will be opposite the Sun in the sky. It will be rising as the sun sets, and it will then officially become an evening planet. Opposition is the time when Saturn is the closest it gets to the Earth, in this case it’s 816 million miles (1 billion 314 million kilometers). In telescopes, we’ll see very little in the way of shadows of the planet on the rings and the rings on the planet, because we are almost directly in line with the Sun and Saturn. We’re actually a little north of the line, so Saturn will exhibit very thin shadows, however a pretty big telescope will be needed to see them. This is the time when Saturn appears largest in telescopes, and the rings are the brightest.

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

Saturn, as realized by the Stellarium planetarium app. It never appears this large in telescopes. The first time I saw Saturn in a telescope, and saw those rings, I was blown away. However, I was disappointed as to how small it was. Well, it is almost a billion miles (1.6 million kilometers) away, about twice as far as Jupiter. The extent of the rings are about as long as Jupiter’s apparent diameter, which averages about half of Saturn’s distance. Currently, the rings are getting more and more edge-on to us. The rings will be edge-on to us on March 23, 2025, nearly a year and a half from now, then begin to open up again. This is due to Saturn’s axial tilt of nearly 27 degrees, and the fact that the rings orbit the planet at its equator.

Categories: Ephemeris Program, Observing, Saturn Tags:

Ephemeris: 08/24/2023 – The Moon will pass in front of the star Antares tonight

August 24, 2023 Comments off

This is Ephemeris for Thursday, August 24th. Today the Sun will be up for 13 hours and 38 minutes, setting at 8:33, and it will rise tomorrow at 6:56. The Moon, at first quarter today, will set at 12:11 tomorrow morning. | Tonight the Moon is going to pass in front of the bright reddish star in Antares in Scorpius scorpion. The event is called an occultation, and it is the only one of the monthly occultations which we’re going to be able to see in this series that began last month and will extend to August 2028. Antares will disappear at the lower left edge of the dark or night part of the Moon at approximately 10:28 pm* this evening, and it’ll stay hidden until 11:32 pm* when it will pop out on the lower right edge of the bright part of the Moon. Start looking for Antares early, probably with binoculars, because the Moon will be quite bright and might overpower Antares when viewed by the naked eye. Hoping for clear skies tonight.

*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. For other locations a planetarium computer app like Stellarium can be used to graphically predict occultation timings within a few minutes. Check your planetarium app, and set it to use Topocentric coordinates. In Stellarium, the selection is in the Configuration window, Tools tab. Check everything under Topocentric coordinates. That way the position of the Moon in the sky will be based on the chosen location, rather than the center of the Earth.

Addendum

A time-lapse prediction of the occultation of Antares by the Moon based on Stellarium imagery. In the actual occultation Antares will wink out and on suddenly. Antares is a double star, with a 5th magnitude companion. It should wink out and in 9 seconds before the main first magnitude star.

World map showing the area where the occultation of Antares can be visible. It is the area bounded by the white line, the red dotted line and the floppy figure 8 is the area where the occultation is visible. The red line shows that the area near that part of the line is where the occultation occurs during daylight the solid white line on the bottom encloses there is where the occultation will be seen at night. Michigan is close to that cyan line and so the occultation will occur near moonset. Credit: Occult 4 app.

Categories: Astronomical Event, Ephemeris Program, Observing, Occultation, The Moon, Uncategorized Tags: