Ephemeris: 08/01/2023 – Looking ahead to August skies
This is Ephemeris for Tuesday, August 1st. Today the Sun will be up for 14 hours and 39 minutes, setting at 9:08, and it will rise tomorrow at 6:29. The Moon, at full today, will rise at 9:44 this evening.
Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 39 minutes today to 13 hours 17 minutes on the 31st. The altitude of the Sun at local noon, that is degrees of angle above the southern horizon, will decrease from 63 degrees today to just over 53 degrees on the 31st. Straits area listeners can subtract one more degree from those angles. Local noon, when the Sun is due south, is about 1:43 p.m. The Perseid meteor shower will reach its peak on the morning of the13th. The Moon will not interfere until it rises at 3:39 am, but then it’s only a waning crescent. A few Perseid meteors can be seen even now, nearly two weeks before the peak. They will seem to come from the northeastern part of the sky.
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
August Evening Star Chart
The planets and stars are plotted for the 15th at 10 pm EDT in the evening and 5 am. 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.
Note the chart times 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. The planet positions are updated each Wednesday on this blog. See them for planet positions on dates other than the 15th.
August Morning Star Chart
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.
- PerR is the radiant of the Perseid meteor shower (Peaks on the morning of the 13th)
Twilight Limits, Nautical and Astronomical
| EDT | |||||||
| Morning | Twilight | Evening | Twilight | Dark | Night | Moon | |
| Date | Astro. | Nautical | Nautical | Astro. | Start | End | Illum. |
| 2023-08-01 | 4h30m | 5h19m | 22h27m | 23h16m | – | – | 1.00 |
| 2023-08-02 | 4h32m | 5h20m | 22h26m | 23h14m | – | – | 0.97 |
| 2023-08-03 | 4h34m | 5h22m | 22h24m | 23h12m | – | – | 0.91 |
| 2023-08-04 | 4h36m | 5h23m | 22h22m | 23h09m | – | – | 0.83 |
| 2023-08-05 | 4h38m | 5h25m | 22h21m | 23h07m | 23h07m | 23h23m | 0.74 |
| 2023-08-06 | 4h40m | 5h26m | 22h19m | 23h05m | 23h05m | 23h43m | 0.63 |
| 2023-08-07 | 4h42m | 5h28m | 22h17m | 23h03m | 23h03m | – | 0.52 |
| 2023-08-08 | 4h44m | 5h29m | 22h15m | 23h01m | 23h01m | 0h06m | 0.42 |
| 2023-08-09 | 4h46m | 5h31m | 22h14m | 22h59m | 22h59m | 0h32m | 0.32 |
| 2023-08-10 | 4h47m | 5h32m | 22h12m | 22h57m | 22h57m | 1h04m | 0.23 |
| 2023-08-11 | 4h49m | 5h34m | 22h10m | 22h54m | 22h54m | 1h44m | 0.15 |
| 2023-08-12 | 4h51m | 5h35m | 22h08m | 22h52m | 22h52m | 2h32m | 0.09 |
| 2023-08-13 | 4h53m | 5h37m | 22h06m | 22h50m | 22h50m | 3h28m | 0.04 |
| 2023-08-14 | 4h55m | 5h38m | 22h05m | 22h48m | 22h48m | 4h31m | 0.01 |
| 2023-08-15 | 4h57m | 5h40m | 22h03m | 22h46m | 22h46m | 4h57m | 0.00 |
| 2023-08-16 | 4h58m | 5h41m | 22h01m | 22h43m | 22h43m | 4h58m | 0.01 |
| 2023-08-17 | 5h00m | 5h43m | 21h59m | 22h41m | 22h41m | 5h00m | 0.03 |
| 2023-08-18 | 5h02m | 5h44m | 21h57m | 22h39m | 22h39m | 5h02m | 0.07 |
| 2023-08-19 | 5h04m | 5h45m | 21h55m | 22h37m | 22h37m | 5h04m | 0.13 |
| 2023-08-20 | 5h06m | 5h47m | 21h53m | 22h34m | 22h34m | 5h06m | 0.20 |
| 2023-08-21 | 5h07m | 5h48m | 21h51m | 22h32m | 22h49m | 5h07m | 0.28 |
| 2023-08-22 | 5h09m | 5h50m | 21h49m | 22h30m | 23h10m | 5h09m | 0.38 |
| 2023-08-23 | 5h11m | 5h51m | 21h47m | 22h28m | 23h37m | 5h11m | 0.48 |
| 2023-08-24 | 5h13m | 5h53m | 21h45m | 22h25m | – | 5h13m | 0.59 |
| 2023-08-25 | 5h14m | 5h54m | 21h43m | 22h23m | 0h12m | 5h14m | 0.69 |
| 2023-08-26 | 5h16m | 5h56m | 21h41m | 22h21m | 0h58m | 5h16m | 0.79 |
| 2023-08-27 | 5h18m | 5h57m | 21h39m | 22h19m | 2h00m | 5h18m | 0.88 |
| 2023-08-28 | 5h19m | 5h58m | 21h37m | 22h17m | 3h15m | 5h19m | 0.95 |
| 2023-08-29 | 5h21m | 6h00m | 21h35m | 22h14m | 4h39m | 5h21m | 0.99 |
| 2023-08-30 | 5h22m | 6h01m | 21h33m | 22h12m | – | – | 1.00 |
| 2023-08-31 | 5h24m | 6h03m | 21h31m | 22h10m | – | – | 0.98 |
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
Aug 1 Tu Venus: 18.7° E
1 Tu 2:31 pm Full Sturgeon Moon
2 We 1:52 am Moon Perigee: 357,300 km
3 Th 6:21 am Moon-Saturn: 2.4° N
6 Su 10:46 pm Moon Ascending Node
8 Tu 5:41 am Moon-Jupiter: 3° S
8 Tu 6:28 am Last Quarter
9 We 8:16 am Moon-Pleiades: 1.6° N
9 We 9:59 pm Mercury Elongation: 27.4° E
12 Sa 3:39 am Moon North Dec.: 28° N
13 Su 3:02 am Mercury-Mars: 4.7° N
13 Su 3:29 am Perseid Meteor Shower: ZHR = 90
13 Su 7:10 am Venus Inferior Conj.
13 Su 5:36 pm Moon-Pollux: 1.9° N
16 We 5:38 am New Moon
16 We 7:55 am Moon Apogee: 406,600 km
18 Fr 7:06 pm Moon-Mars: 2.4° S
21 Mo 5:28 am Moon-Spica: 2.8° S
21 Mo 12:23 pm Moon Descending Node
24 Th 5:57 am First Quarter
24 Th 9:30 pm Moon-Antares: 1.1° S
26 Sa 4:22 pm Moon South Dec.: 28.1° S
27 Su 3:52 am Saturn Opposition
30 We 11:51 am Moon Perigee: 357,200 km
30 We 2:03 pm Moon-Saturn: 2.4° N
30 We 9:35 pm Full Blue Moon
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
August 2023 Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM |
| | RISE SET HOURS | END START |PHASE SET** TIME FRACTN|
+=======================================================================+
|Tue 1| 06:28a 09:08p 14:39 | 11:12p 04:24a |Full Rise 09:44p 100%|
|Wed 2| 06:29a 09:07p 14:37 | 11:10p 04:26a | Rise 10:15p 98%|
|Thu 3| 06:31a 09:06p 14:35 | 11:08p 04:28a | Rise 10:40p 92%|
|Fri 4| 06:32a 09:04p 14:32 | 11:06p 04:30a | Rise 11:02p 85%|
|Sat 5| 06:33a 09:03p 14:30 | 11:04p 04:31a | Rise 11:22p 76%|
+------+-----------------------+----------------+-----------------------+
|Sun 6| 06:34a 09:02p 14:27 | 11:01p 04:33a | Rise 11:43p 65%|
|Mon 7| 06:35a 09:00p 14:25 | 10:59p 04:35a | Rise 12:06a 55%|
|Tue 8| 06:36a 08:59p 14:22 | 10:57p 04:37a |L Qtr Rise 12:32a 44%|
|Wed 9| 06:37a 08:57p 14:19 | 10:55p 04:39a | Rise 01:04a 34%|
|Thu 10| 06:39a 08:56p 14:17 | 10:53p 04:41a | Rise 01:43a 25%|
|Fri 11| 06:40a 08:54p 14:14 | 10:51p 04:43a | Rise 02:32a 17%|
|Sat 12| 06:41a 08:53p 14:12 | 10:48p 04:45a | Rise 03:28a 10%|
+------+-----------------------+----------------+-----------------------+
|Sun 13| 06:42a 08:51p 14:09 | 10:46p 04:47a | Rise 04:30a 5%|
|Mon 14| 06:43a 08:50p 14:06 | 10:44p 04:48a | Rise 05:35a 2%|
|Tue 15| 06:44a 08:48p 14:03 | 10:42p 04:50a | Rise 06:41a 0%|
|Wed 16| 06:46a 08:47p 14:01 | 10:40p 04:52a |New Set 09:21p 0%|
|Thu 17| 06:47a 08:45p 13:58 | 10:37p 04:54a | Set 09:40p 2%|
|Fri 18| 06:48a 08:44p 13:55 | 10:35p 04:56a | Set 09:57p 6%|
|Sat 19| 06:49a 08:42p 13:52 | 10:33p 04:57a | Set 10:13p 11%|
+------+-----------------------+----------------+-----------------------+
|Sun 20| 06:50a 08:40p 13:49 | 10:31p 04:59a | Set 10:30p 18%|
|Mon 21| 06:52a 08:39p 13:47 | 10:28p 05:01a | Set 10:48p 26%|
|Tue 22| 06:53a 08:37p 13:44 | 10:26p 05:03a | Set 11:09p 36%|
|Wed 23| 06:54a 08:35p 13:41 | 10:24p 05:05a | Set 11:36p 46%|
|Thu 24| 06:55a 08:33p 13:38 | 10:22p 05:06a |F Qtr Set 12:11a 56%|
|Fri 25| 06:56a 08:32p 13:35 | 10:19p 05:08a | Set 12:57a 67%|
|Sat 26| 06:57a 08:30p 13:32 | 10:17p 05:10a | Set 01:59a 77%|
+------+-----------------------+----------------+-----------------------+
|Sun 27| 06:59a 08:28p 13:29 | 10:15p 05:11a | Set 03:14a 86%|
|Mon 28| 07:00a 08:26p 13:26 | 10:13p 05:13a | Set 04:38a 93%|
|Tue 29| 07:01a 08:25p 13:23 | 10:10p 05:15a | Set 06:05a 98%|
|Wed 30| 07:02a 08:23p 13:20 | 10:08p 05:16a |Full Rise 08:39p 100%|
|Thu 31| 07:03a 08:21p 13:17 | 10:06p 05:18a | Rise 09:02p 99%|
+-----------------------------------------------------------------------+
* Astronomical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset
Generated using my LookingUp for DOS program.
Ephemeris: 07/31/2023 – August’s Blue Moon
This is Ephemeris for Monday, July 31st. Today the Sun will be up for 14 hours and 42 minutes, setting at 9:10, and it will rise tomorrow at 6:28. The Moon, 1 day before full, will set at 5:45 tomorrow morning.
In August, we are going to have two full moons this year and by most modern reckoning the second full moon is called a Blue Moon, even though that’s not the color of the Moon, which looks like normal although both of these moons in August will be supermoons, so they’ll be a little bit larger than average. However, there is nothing to compare them to, so there’s no way of determining this visually for yourself. The older definition of blue moon is the third full moon in a season that has four full moons. Being a purist, I prefer the latter definition, but I seem to be in a minority. The months of our calendar are a result of Roman politics and superstition, an arbitrary construct. So are time zones by modern politicians. Some time zones could have a blue moon, and some not.
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
Ephemeris: 07/28/2023 – Sun and Star Party scheduled for tomorrow at the Sleeping Bear Dunes
This is Ephemeris for Friday, July 28th. Today the Sun will be up for 14 hours and 49 minutes, setting at 9:13, and it will rise tomorrow at 6:25. The Moon, 3 days past first quarter, will set at 2:19 tomorrow morning.
Tomorrow, the Sleeping Bear Dunes National Lakeshore and the Grand Traverse Astronomical Society will host a Sun and Star Party at the Dune Climb area of the park. There will be a solar viewing period from 5 pm to about 7 pm. The society has two hydrogen alpha solar telescopes to view the Sun’s chromosphere and prominences. Plus, some members also have solar scopes and white light filtered telescopes to view sunspots on the face of the Sun. Night viewing will start at 9 pm with the Moon featured, along with the brighter telescopic wonders of summer. The park rangers will leave at 11 pm, but society members will stay later to get a good view of Saturn as it moves higher in the sky. All this will happen only if clouds permit.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
There will be a pass of the International Space Station starting in the WNW at 9:48 pm, reaching maximum altitude at 9:52 pm of 63o in the SW, entering the Earth’s shadow at 9:55 pm. Note, these are specific times to the nearest minute for the Dune Climb, but close for the Grand Traverse area of Michigan. For other locations, go to: heavens-above.com.
Ephemeris: 07/27/2023 – See the Moon’s Bay of Rainbows at sunrise
This is Bob Moler with Ephemeris for Thursday, July 27th. Today the Sun will be up for 14 hours and 51 minutes, setting at 9:14, and it will rise tomorrow at 6:24. The Moon, 2 days past first quarter, will set at 1:38 tomorrow morning.
The moon tonight is a waxing gibbous phase, so it’s more than half illuminated by the Sun. The line between light and dark on the left side of the Moon is called the terminator, which before full is the sunrise line. It is where we can see the greatest detail because the Sun is low in the Moon’s sky there, and creates the longest shadows. Compare it to the right side of the Moon which is seen at nearly solar noon where no shadows are seen, so it has a very bland appearance. One of the cool features of the gibbous moon tonight is Sinus Iridium, the Bay of Rainbows, which is on the upper left part of the terminator. Part of the mountain range that partially rings it is seen in sunlight, while that floor of the bay is still in shadow.
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
Ephemeris: 07/26/2023 – Let’s find out where the naked-eye planets have wandered off to this week
This is Bob Moler with Ephemeris for Wednesday, July 26th. Today the Sun will be up for 14 hours and 53 minutes, setting at 9:15, and it will rise tomorrow at 6:23. The Moon, 1 day past first quarter, will set at 1:08 tomorrow morning. | Let’s find out where the naked-eye planets have wandered off to this week. Venus is our hard to find Evening Star, seen very low in the west in evening twilight by 9:45 pm. It will set at 10:11 pm, Mercury might be spotted to Venus’ right and a bit above. The red planet Mars is pretty much lost in the evening twilight, above and left of Venus. Saturn will rise at 10:38 pm. And by 5:30 am, or a bit less than an hour before sunrise tomorrow, it will appear in the south-southwest, the brightest “star” in that direction. Its above the bright star Fomalhaut, normally the loneliest bright star in the sky. Jupiter will be in the east-southeast at that hour. Jupiter is the brightest star-like object in the morning sky now, near some of the bright stars of a winter’s evening.
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
Ephemeris: 07/25/2023 – Is the universe twice as old as we think?
This is Ephemeris for Tuesday, July 25th. Today the Sun will be up for 14 hours and 55 minutes, setting at 9:16, and it will rise tomorrow at 6:22. The Moon, at first quarter today, will set at 12:44 tomorrow morning.
Is the universe twice as old as we thought? That’s a conclusion of a study printed in the monthly notices of the Royal Astronomical Society by Rajendra Gupta from the University of Ottawa, in which he postulates that the structure and chemical composition of very early galaxies found by the James Webb Space Telescope turn out to be more developed than one would expect for objects so soon after The Big Bang. The problem with hypothesizing an older universe is to explain what we see currently that have shown that the universe is 13.8 billion years old. One of the things he hypothesized was something called tired light, where light loses energy and is red-shifted not just because of the expansion of the universe but over time and distance. Stay tuned.
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
Timeline of the universe. A representation of the evolution of the universe over 13.77 billion years. The far left depicts the earliest moment we can now probe, when a period of “inflation” produced a burst of exponential growth in the universe. (Size is depicted by the vertical extent of the grid in this graphic.) For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe. The afterglow light seen by WMAP was emitted about 375,000 years after inflation and has traversed the universe largely unimpeded since then. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the universe. Public Domain.
Diagram is from Wikipedia. Above is the expansion of the universe as commonly understood. Not mentioned in the program script above, is the requirement, according to Gupta’s hypothesis, that the basic constants of the universe change over time. As Carl Sagan explained, “Extraordinary claims require extraordinary evidence.” So more evidence is needed. His hypothesis won’t be the only explanation put forth, so there will be more to test. That’s job security for astrophysicists and cosmologists.
Ephemeris: 07/24/2023 – The Moon appears to wobble a bit
This is Ephemeris for Monday, July 24th. Today the Sun will be up for 14 hours and 57 minutes, setting at 9:17, and it will rise tomorrow at 6:21. The Moon, 1 day before first quarter, will set at 12:24 tomorrow morning.
The Moon tonight is nearly half illuminated. In binoculars the dark oval spot visible on the Moon’s right edge is the Sea of Crises or Mare Crisium a small dark lava plain. The Moon’s rotation is quite uniform, however its orbit isn’t circular, so the Moon’s motion in its orbit slows as it moves farthest from the Earth, called apogee, and is sped up when closest, at perigee, So its face seems to rock a bit back and forth over the month. It’s an effect called libration. And one way to track that is to note how close the Mare Crisium (Sea of Crises) is to the edge of the Moon. It appears close to the right edge now. A week from now, that sea will appear to move away from the edge. Unfortunately, by then the Moon will be full, and night will soon fall on that little sea.
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
Ephemeris: 07/21/2023 – Antares just looks weird
This is Ephemeris for Friday, July 21st. Today the Sun will be up for 15 hours and 3 minutes, setting at 9:20, and it will rise tomorrow at 6:18. The Moon, halfway from new to first quarter, will set at 11:34 this evening.
We’ve had our Fourth of July fireworks over two weeks ago, but there’s one star still celebrating as a sparkler. That’s Antares in Scorpius the scorpion low in the south tonight. We in Michigan always see Antares low in the south. It’s a bright red giant star which twinkles mightily, and since it’s low in the sky, it spits and sputters all kinds of colors due to our atmosphere’s turbulence, and the fact that we’re looking through so much of it at Antares. At it’s highest, due south, we are seeing it though 3 times more atmosphere than we would be if it was overhead. The more magnification one uses with binoculars or a telescope, the greater the sparkler effect. It is even called in sometimes as a UFO.
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 name of the star Antares means “Rival of Mars”. “Ant” meaning anti, “Ares”, the Greek equivalent to the Roman god Mars. The reason is their similar reddish color. Antares is red because it is a cool star, a red giant. Mars is red due to its red dust, colored by iron rust. The planet passes Antares about every 23 1/2 months. Mars will next pass Antares on December 8th, 2023. However, the event will not be visible, because both the star and the planet will be too close to the Sun in the morning sky then. Their next meeting, or conjunction, after that, on November 17th, 2025 will be in the evening sky, but still too close to the Sun to be spotted. The conjunction after that will be in the evening sky, again rather close to the Sun, on October 28, 2027. For these three encounters, Mars will be north or above Antares, and dimmer than the star.
Ephemeris: 07/20/2023 – How Boötes and Ursa Major got into the sky
This is Ephemeris for Thursday, July 20th. Today the Sun will be up for 15 hours and 5 minutes, setting at 9:21, and it will rise tomorrow at 6:17. The Moon, 3 days past new, will set at 11:16 this evening.
Seen in high in the west-southwest at 10:30 this evening is the kite shaped constellation of Boötes (pronounced Bo-o-tees) the herdsman. The bright star Arcturus is at the bottom of the kite. It is pointed to by the arc of the handle of the Big Dipper, part of Ursa Major, the Great Bear, over toward the northwest. Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young lady who had the misfortune of being loved by Zeus, the chief of the Greek gods. Zeus’ wife, Hera, found out about it, and since she couldn’t punish Zeus, turned the poor woman into a bear. Arcas, many years later, unaware of the events surrounding his mother’s disappearance, was about to kill the bear when Jupiter intervened and placed them both in the sky to save her. Arcas still pursues her across the sky nightly.
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
Ephemeris: 07/19/2023 – Let’s find out where the naked-eye planets have wandered off to this week
This is Ephemeris for Wednesday, July 19th. Today the Sun will be up for 15 hours and 7 minutes, setting at 9:22, and it will rise tomorrow at 6:16. The Moon, 2 days past new, will set at 10:55 this evening.
Let’s find out where the naked-eye planets have wandered off to this week. Venus is our blazing Evening Star, seen very low in the west in evening twilight. It will set at 10:31 pm, and by four minutes earlier each night. The red planet Mars is now pretty much lost in the evening twilight. We’ll see it in the morning sky in a few months. Venus too will soon leave the evening sky. Saturn will rise shortly after 11 pm. And by 5:15 am, or an hour before sunrise, it will appear in the south-southwest, the brightest “star” in that direction. It’s above the bright star Fomalhaut, normally the loneliest bright star in the sky. Jupiter will be in the east-southeast 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
