08/31/2021 – Ephemeris – Previewing September skies

This is Bob Moler with Ephemeris for Tuesday, August 31st. Today the Sun will be up for 13 hours and 16 minutes, setting at 8:20, and it will rise tomorrow at 7:05. The Moon, 1 day past last quarter, will rise at 1:07 tomorrow morning.

Let’s look at the skies for the month of September. The sun will be moving at its greatest speed in its retreat to the south. Daylight hours in the Interlochen/Traverse City area and will drop from 13 hours and 13 minutes tomorrow to 11 hours and 44 minutes on the 30th. The altitude of the Sun above the southern horizon at local noon will be 54 degrees tomorrow, and will descend to 42 degrees on the 30th. Local noon at mid-month will be around 1:37 pm. The season of summer is getting short, so enjoy it while you can. Summer ends and autumn begins at 3:21 p.m. on September 22nd, the autumnal equinox. This year the Harvest Moon, the nearest full moon to the equinox, will fall two days before it on the 20th.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

September Star Chart

Star Chart for September 2021. Created using my LookingUp program. Click 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 2021 (10 p.m. EDT, September 15, 2021). 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.
2021-09-01	5h26m	6h04m	21h28m	22h06m	22h06m	1h07m	0.24
2021-09-02	5h28m	6h06m	21h26m	22h04m	22h04m	1h57m	0.16
2021-09-03	5h29m	6h07m	21h24m	22h02m	22h02m	2h55m	0.09
2021-09-04	5h31m	6h08m	21h22m	22h00m	22h00m	4h01m	0.04
2021-09-05	5h32m	6h10m	21h20m	21h57m	21h57m	5h11m	0.01
2021-09-06	5h34m	6h11m	21h18m	21h55m	21h55m	5h34m	0
2021-09-07	5h35m	6h12m	21h16m	21h53m	21h53m	5h35m	0.02
2021-09-08	5h37m	6h14m	21h14m	21h51m	21h51m	5h37m	0.06
2021-09-09	5h38m	6h15m	21h12m	21h49m	21h49m	5h38m	0.13
2021-09-10	5h40m	6h16m	21h10m	21h46m	22h06m	5h40m	0.21
2021-09-11	5h41m	6h18m	21h08m	21h44m	22h35m	5h41m	0.32
2021-09-12	5h43m	6h19m	21h06m	21h42m	23h12m	5h43m	0.43
2021-09-13	5h44m	6h20m	21h04m	21h40m	23h57m	5h44m	0.54
2021-09-14	5h46m	6h22m	21h02m	21h38m	–	5h46m	0.65
2021-09-15	5h47m	6h23m	21h00m	21h36m	0h53m	5h47m	0.76
2021-09-16	5h48m	6h24m	20h58m	21h34m	1h59m	5h48m	0.84
2021-09-17	5h50m	6h25m	20h56m	21h31m	3h10m	5h50m	0.91
2021-09-18	5h51m	6h27m	20h54m	21h29m	4h24m	5h51m	0.96
2021-09-19	5h53m	6h28m	20h52m	21h27m	5h37m	5h53m	0.99
2021-09-20	5h54m	6h29m	20h50m	21h25m	–	–	1
2021-09-21	5h55m	6h31m	20h48m	21h23m	–	–	0.99
2021-09-22	5h57m	6h32m	20h46m	21h21m	–	–	0.95
2021-09-23	5h58m	6h33m	20h44m	21h19m	–	–	0.9
2021-09-24	6h00m	6h34m	20h42m	21h17m	21h17m	21h26m	0.84
2021-09-25	6h01m	6h36m	20h40m	21h15m	21h15m	21h52m	0.76
2021-09-26	6h02m	6h37m	20h38m	21h13m	21h13m	22h23m	0.67
2021-09-27	6h04m	6h38m	20h36m	21h11m	21h11m	23h00m	0.58
2021-09-28	6h05m	6h39m	20h34m	21h09m	21h09m	23h46m	0.49
2021-09-29	6h06m	6h41m	20h32m	21h07m	21h07m	–	0.39
2021-09-30	6h07m	6h42m	20h31m	21h05m	21h05m	0h40m	0.3

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

Sep  1  We            Venus: 39.9° E
     1  We   8:23 pm  Moon North Dec.: 25.9° N
     4  Sa  12:07 am  Moon-Beehive: 3.1° S
     5  Su  10:32 am  Venus-Spica: 1.6° N
     6  Mo   8:52 pm  New Moon
     9  Th  10:09 pm  Moon-Venus: 4.1° S
    11  Sa   6:06 am  Moon Perigee: 368500 km
    12  Su  12:35 pm  Moon Descending Node
    13  Mo   4:39 pm  First Quarter
    13  Mo  11:59 pm  Mercury Elongation: 26.8° E
    14  Tu   4:10 am  Neptune Opposition
    14  Tu  11:48 pm  Moon South Dec.: 26° S
    16  Th  10:37 pm  Moon-Saturn: 3.9° N
    18  Sa   2:50 am  Moon-Jupiter: 4.1° N
    20  Mo   7:55 pm  Full Moon, Harvest Moon 
    20  Mo  10:03 pm  Mercury-Spica: 1.4° S
    22  We   3:21 pm  Autumnal Equinox
    26  Su   3:33 am  Moon Ascending Node
    26  Su   5:44 pm  Moon Apogee: 404600 km
    28  Tu   9:57 pm  Last Quarter
    29  We   4:26 am  Moon North Dec.: 26.1° N
Oct  1  Fr            Venus: 44.9° E

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

LU                  Ephemeris of Sky Events for Interlochen/TC
September, 2021    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Wed  1| 07:05a  08:18p  13:13 | 09:25p  05:59a |      Rise 01:57a   25%|
|Thu  2| 07:06a  08:17p  13:10 | 09:23p  06:00a |      Rise 02:55a   17%|
|Fri  3| 07:07a  08:15p  13:07 | 09:21p  06:01a |      Rise 04:01a   10%|
|Sat  4| 07:09a  08:13p  13:04 | 09:18p  06:03a |      Rise 05:11a    5%|
+------+-----------------------+----------------+-----------------------+
|Sun  5| 07:10a  08:11p  13:01 | 09:16p  06:04a |      Rise 06:24a    1%|
|Mon  6| 07:11a  08:09p  12:58 | 09:14p  06:06a |New   Set  08:30p    0%|
|Tue  7| 07:12a  08:07p  12:55 | 09:12p  06:07a |      Set  08:53p    1%|
|Wed  8| 07:13a  08:06p  12:52 | 09:10p  06:08a |      Set  09:16p    5%|
|Thu  9| 07:14a  08:04p  12:49 | 09:08p  06:10a |      Set  09:40p   11%|
|Fri 10| 07:16a  08:02p  12:46 | 09:06p  06:11a |      Set  10:05p   19%|
|Sat 11| 07:17a  08:00p  12:43 | 09:04p  06:12a |      Set  10:35p   29%|
+------+-----------------------+----------------+-----------------------+
|Sun 12| 07:18a  07:58p  12:40 | 09:02p  06:13a |      Set  11:12p   40%|
|Mon 13| 07:19a  07:56p  12:37 | 09:00p  06:15a |F Qtr Set  11:57p   52%|
|Tue 14| 07:20a  07:54p  12:33 | 08:58p  06:16a |      Set  12:53a   63%|
|Wed 15| 07:21a  07:52p  12:30 | 08:56p  06:17a |      Set  01:59a   73%|
|Thu 16| 07:23a  07:51p  12:27 | 08:54p  06:19a |      Set  03:10a   82%|
|Fri 17| 07:24a  07:49p  12:24 | 08:52p  06:20a |      Set  04:24a   90%|
|Sat 18| 07:25a  07:47p  12:21 | 08:50p  06:21a |      Set  05:37a   95%|
+------+-----------------------+----------------+-----------------------+
|Sun 19| 07:26a  07:45p  12:18 | 08:48p  06:23a |      Set  06:47a   99%|
|Mon 20| 07:27a  07:43p  12:15 | 08:46p  06:24a |Full  Rise 08:03p  100%|
|Tue 21| 07:29a  07:41p  12:12 | 08:44p  06:25a |      Rise 08:23p   99%|
|Wed 22| 07:30a  07:39p  12:09 | 08:42p  06:26a |      Rise 08:43p   96%|
|Thu 23| 07:31a  07:37p  12:06 | 08:40p  06:28a |      Rise 09:03p   91%|
|Fri 24| 07:32a  07:35p  12:03 | 08:39p  06:29a |      Rise 09:26p   85%|
|Sat 25| 07:33a  07:33p  12:00 | 08:37p  06:30a |      Rise 09:52p   78%|
+------+-----------------------+----------------+-----------------------+
|Sun 26| 07:35a  07:32p  11:57 | 08:35p  06:31a |      Rise 10:23p   69%|
|Mon 27| 07:36a  07:30p  11:53 | 08:33p  06:33a |      Rise 11:00p   60%|
|Tue 28| 07:37a  07:28p  11:50 | 08:31p  06:34a |L Qtr Rise 11:46p   51%|
|Wed 29| 07:38a  07:26p  11:47 | 08:29p  06:35a |      Rise 12:40a   41%|
|Thu 30| 07:39a  07:24p  11:44 | 08:27p  06:36a |      Rise 01:42a   32%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

08/30/2021 – Ephemeris – “W”

This is Bob Moler with Ephemeris for Monday, August 30th. Today the Sun will be up for 13 hours and 19 minutes, setting at 8:22, and it will rise tomorrow at 7:04. The Moon, at last quarter today, will rise at 12:26 tomorrow morning.

Rising higher each evening in the northeastern sky is a group of stars that make the pattern of the letter W. It is the constellation of Cassiopeia the queen. It is one of the more recognizable star patterns. From our latitude here in Northern Michigan, it is circumpolar, meaning that it never sets. Though, the best time to see it is in the autumn and winter, when it’s highest in the sky. It is opposite the Big Dipper from Polaris, the north star. In fact, a line drawn from any of the handle stars of the Big Dipper through Polaris will reach Cassiopeia. So as the Big Dipper descends in the northwestern sky now, Cassiopeia ascends in the northeast. They change places in winter and spring as the Big Dipper ascends in the northeast.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Animation showing the juxtaposition of Cassiopeia and the Big Dipper from Polaris, the North Star. Click on the image to enlarge it. Created using Stellarium and GIMP.

08/27/2021 – Ephemeris – As Labor Day approaches, so do the autumn constellations

This is Bob Moler with Ephemeris for Friday, August 27th. Today the Sun will be up for 13 hours and 28 minutes, setting at 8:27, and it will rise tomorrow at 7:00. The Moon, 3 days before last quarter, will rise at 11:01 this evening.

Rising in the east at as it gets dark around 9:30 p.m. we can preview one of the great autumn constellations: Pegasus the flying horse of Greek myth. Its most visible feature is a large square of four stars, now standing on one corner. This feature, called the Great Square of Pegasus, represents the front part of the horse’s body. The horse is quite aerobatic because it is seen flying upside down. Remembering that fact, the neck and head is a bent line of stars extending from the right corner star of the square. Its front legs can be seen in a gallop extending to the upper right from the top star of the square. From the left star extend, not hind legs but the constellation of Andromeda, an important constellation in its own right. The Anishinaabe peoples native to this region saw a right side up Moose (Mooz) in the stars here.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Pegasus image in the stars at 10 pm. Created using Stellarium. Drawing by Johan Meuris.

08/26/2021 – Ephemeris – Two tiny summer constellations

This is Ephemeris for Thursday, August 26th. Today the Sun will be up for 13 hours and 31 minutes, setting at 8:29, and it will rise tomorrow at 6:59. The Moon, half-way from full to last quarter, will rise at 10:40 this evening. | Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is nearly overhead in our sky at 10 p.m., is the tiny constellation of Delphinus the dolphin. Delphinus’ 6 stars, in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do, and told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow a small thin group of 5 stars, which represents Cupid’s dart.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Delphinus and Sagitta finder animation. Created using Stellarium and GIMP.

Comet West, C/1975 V1, as photographed by me at about 6 am, March 8, 1976. The wide, curved dust tail is most prominent, with the narrow blue ion tail streaming more directly away from the rising Sun. The small summer constellation of Delphinus the dolphin is to the upper right. The diamond shape of stars at the front of the dolphin’s body is an asterism called Job’s Coffin.

08/25/2021 – Ephemeris – Let’s search for the naked-eye planets for this week

This is Ephemeris for Wednesday, August 25th. Today the Sun will be up for 13 hours and 34 minutes, setting at 8:31, and it will rise tomorrow at 6:58. The Moon, 3 days past full, will rise at 10:20 this evening.

Let’s search for the naked-eye planets for this week. Venus should be visible in the western evening twilight before 9 tonight. It will set at 9:53 pm. By 9 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. Both these planets will be visible for most of the night, with Saturn setting first at 4:52 am, with Jupiter setting at 6:26 tomorrow morning. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power, the rings won’t appear separated from the planet, so Saturn will look like an elliptical spot. Most of Jupiter’s 4 brightest moon can be spotted in binoculars.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Venus in evening twilight tonight, August 25, 2021 at 9 pm, about 1/2 hour after sunset. Created using Stellarium.

Jupiter and Saturn in the southeast at 9:30 pm tonight, August 25, 2021, about 45 minutes after sunset. Created using Stellarium.

The Moon as it might appear tonight in binoculars or a small telescope at 11:30 pm, about an hour after it rises tonight, August 25, 2021. Created using Stellarium.

Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening. Venus at 9:15 pm, and the other two at 11 pm, August 25, 2021. Apparent diameters: Venus, 14.51″ 75% illuminated; Saturn 18.43″, its rings 42.93″; Jupiter, 49.06″. Jupiter’s moons Io and Ganymede will slowly separate after 11 pm. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).

Planets and the Moon at sunset and sunrise of a single night, starting with sunset on the right on August 25, 2021. The night ends on the left with sunrise on the 26th. Click on the image to enlarge. Created using my LookingUp program.

08/24/2021 – Ephemeris – The Harvest Moon is coming next full moon

This is Bob Moler with Ephemeris for Tuesday, August 24th. Today the Sun will be up for 13 hours and 36 minutes, setting at 8:33, and it will rise tomorrow at 6:57. The Moon, 2 days past full, will rise at 10:00 this evening.

We are at that time of year when the advance in Moon rising times from night to night is shorter than the average 50 minutes per night. Tonight the Moon will rise only 21 minutes later than it did last night, and tomorrow’s Moon will rise 20 minutes later than it will tonight. It’s what I call the harvest moon effect, though Harvest Moon will be next month. I find the effect lasts for three full moons, centered on the start of autumn. That’s because the angle of the Moon’s and also the Sun’s paths in the sky called the ecliptic intersect the horizon at a shallow angle near sunset. It’s also the reason Venus will stay close to the western horizon for its evening appearance this year. The planets also hang around the ecliptic, where the zodiacal constellations are.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

The autumn vs spring sunset ecliptic (orange line). I’m using the autumnal equinox 2021 and vernal equinox 2022 as examples. At the autumnal equinox sunset, the ecliptic runs low in the south, and the ecliptic meets the horizon at a low angle. At the vernal equinox in March, the ecliptic runs very high in the south. It meets the horizon at a steep angle. Click on the image to enlarge it. Created using Stellarium and GIMP.

Near the autumnal equinox, the ecliptic appears low in the south at sunset. Planets near the Sun like Venus are seen low in the west and set soon after sunset. At the opposite end of the sky, a rising Moon near full will rise at less than the 50 minutes later each night average.

08/23/2021 – Ephemeris – Seeking shelter on the Moon

This is Ephemeris for Monday, August 23rd. Today the Sun will be up for 13 hours and 39 minutes, setting at 8:34, and it will rise tomorrow at 6:56. The Moon, 1 day past full, will rise at 9:39 this evening.

The area of interest on the Moon for NASA’s Artemis crewed landing program and the target for Chinese lunar ambitions is the south pole, where signs of water ice have been detected in permanently shadowed craters. That is a valuable resource, if one wants to live off the land on the Moon. There’s another resource that is also valuable in finding: shelter from radiation and the Moon’s extreme temperature swings. Those are lava tubes. They are lava channels in which lava flowed, the top and sides cooled and crusted over. They emptied when the lava ran out, leaving a hollow tube. Sometimes part of the upper crust fails, leaving what is called a skylight. Several of these skylights have been found on the Moon and even Mars.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

A skylight betrays the presence of a lunar lava tube. Credit NASA/LRO.

Here’s an earthly lava tube on the Island of Hawai’i, I visited in 2012 with my wife. It was on the site of a coffee plantation south of Kona. Credit mine.

08/20/2021 – Ephemeris – The Moon will pass Saturn tonight

This is Bob Moler with Ephemeris for Friday, August 20th. Today the Sun will be up for 13 hours and 48 minutes, setting at 8:39, and it will rise tomorrow at 6:52. The Moon, 2 days before full, will set at 5:26 tomorrow morning.

The Moon is passing Saturn this evening. Saturn will be directly above the Moon by about 10 moon-widths or five degrees at 10 pm tonight. Tomorrow night the Moon will have moved toward Jupiter, which at the same time of night, the planet will appear to the upper left of our satellite. The sky appears to us to be a dome over us, which is useful for imagining the constellations, navigation, and pointing telescopes. However, that is an illusion. The night sky is impossibly and wonderfully deep. The Moon is a quarter of a million miles away, Jupiter and Saturn are hundreds of million miles away. The nearest nighttime stars are trillions of miles away, and so on as far as our eyes and instruments can see.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Animation showing the Moon passing Saturn and Jupiter at 10 pm on August 20 & 21, 2021. Beside the Moon jumping position between the two dates, the planets and stars do too, but to a lesser extent to the right. This is due to the Earth’s change in position as it orbits the Sun. Stars rise and set 3 minutes, 56 seconds earlier each night. The Created using Stellarium and GIMP.

08/19/2021 – Ephemeris – Jupiter is at opposition today!

This is Ephemeris for Thursday, August 19th. Today the Sun will be up for 13 hours and 51 minutes, setting at 8:41, and it will rise tomorrow at 6:51. The Moon, 3 days before full, will set at 4:11 tomorrow morning.

Tonight, Jupiter will be at opposition. That’s a shortcut term for Jupiter being opposite the Sun in our sky. At that time, Jupiter rises at sunset and sets at sunrise. It is also at its closest to us. It also officially becomes an evening planet, available in the evening for those of us with daytime jobs. In even small telescopes, Jupiter shows two dark bands. There’s more, but those two are the most prominent. Its four largest moons will be visible before 9:50 pm tonight, after that the innermost of the four, Io, will start to cross the face of Jupiter. It will leave Ganymede on Jupiter’s east side. On the west side will be the moon Europa, and farther out, Callisto. At 12:08 am, Io will reappear on the west side of Jupiter, joining Europa and Callisto. The moons do put on a show.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Jupiter’s Galilean moons at two times tonight, August 19th at 9:30 pm (01:30 on the 20th, UT) and 12:30 am (04:30 UT). From 9:50 pm to 12:08 am (01:50 – 04:08 UT), Io will pass in front of Jupiter and be practically invisible. Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).

08/18/2021 – Ephemeris – Let’s search for the naked-eye planets for this week

This is Bob Moler with Ephemeris for Wednesday, August 18th. Today the Sun will be up for 13 hours and 54 minutes, setting at 8:43, and it will rise tomorrow at 6:50. The Moon, 3 days past first quarter, will set at 3:02 tomorrow morning.

Let’s search for the naked-eye planets for this week. Venus should be visible in the western evening twilight by 9:15 tonight. It will set at 10:04 pm. By 9:30 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. Jupiter, just a day from opposition from the Sun, will be at its brightest and closest to us. It’s now 373 million miles (600 million km) from us. It won’t change much by tomorrow. Actually it’s a closer approach than average, so it’s brighter than at an average opposition and larger appearing than normal in telescopes. Jupiter and four of its largest moons always provide for a great show.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

Venus low in the west, tonight at 9:15, about a half hour after sunset, August 18, 2021. Created using Stellarium.

Jupiter, Saturn and the Moon at 10 pm, about an hour and a quarter after sunset tonight, August 18, 2021. Click on the image to enlarge it. Created using Stellarium.

The waxing gibbous Moon as it might appear tonight in binoculars or a small telescope. Created using Stellarium.

Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening. Venus at 10 pm, and the other two at 11 pm, August 18, 2021. Apparent diameters: Venus, 13.93″; Saturn 18.51″, its rings 43.13″; Jupiter, 49.12″. Jupiter’s moon have a cluster of events in the am hours. See below. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).

Satellite  Event             EDT (UT-4)   UT 
Europa     Shadow start      12:34 am     04:34
Europa	   Transit start     12:37 am     04:37
Io         Occultation start 12:37 am     04:37
Ganymede   Eclipse start     12:43 am     04:43
Io         Occultation end    2:55 am     06:55
Europa     Shadow end         3:25 am     07:25
Europa     Transit end        3:27 am     07:27
Ganymede   Occultation end    4:24 am     08:24

From 12:43 to 2:55 am, only Callisto of the four Galilean moons will be visible.

The above times were determined using Stellarium, and may be off by several minutes.
Shadow events are when a satellite’s shadow is cast onto the face of the planet
Transit events are when the satellite passes in front of the planet. The satellite is usually not visible
Eclipse events are when a satellite passes through the planet’s shadow
Occultation events are when the satellite passes behind the planet

The naked-eye planets and the Moon are shown at sunset and sunrise of a single night, starting with sunset on the right on August 18, 2021. The night ends on the left with sunrise on the 19th. Mars and Mercury will be in conjunction in Leo that evening, so their labels overlap. Click on the image to enlarge. Created using my LookingUp program.