Ephemeris: 05/14/2024 – Last Friday’s geomagnetic storm

This is Ephemeris for Tuesday, May 14th. Today the Sun will be up for 14 hours and 48 minutes, setting at 9:03, and it will rise tomorrow at 6:13. The Moon, 1 day before first quarter, will set at 3:08 tomorrow morning.

Last Friday night’s displays of the Northern Lights were seen as far as the Caribbean, making the greatest what is called a geomagnetic storm of the last 20 years, and up there with the greatest storms ever recorded. Last Wednesday there was an immense solar flare coming from a large sunspot group on the Sun. That group was large enough to be able to be seen with eclipse glasses. So you might want to keep those eclipse glasses handy, and check out the Sun every once in a while. Only the largest sunspot groups will be visible. The flare causes the ejection of the part of the Sun’s corona, what astronomers call the coronal mass ejection or CME for short. These charged particles were intercepted by the Earth’s magnetic field and caused the aurora we saw.

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 eruption of a CME, on May 8 that caused the aurora on the 10th recorded by the C3 coronagraph on the Solar and Heliospheric Observatory (SOHO) satellite in halo orbit of the Earth-Sun L1 point, a million miles sunward of the Earth. A coronagraph produces an artificial total solar eclipse using a disk in place of the moon to block the bright disk of the Sun. The two bright stars are the planets Jupiter on the left and Venus on the right. They will both cross behind the Sun with Jupiter leaving the evening sky and entering the morning sky and Venus leaving the morning sky and entering the evening sky. Credit: ESA. NASA.

Ephemeris: 05/13/2024 – Viewing the Moon tonight

This is Bob Moler with Ephemeris for Monday, May 13th. Today the Sun will be up for 14 hours and 46 minutes, setting at 9:02, and it will rise tomorrow at 6:15. The Moon, 2 days before first quarter, will set at 2:44 tomorrow morning.

The crescent Moon tonight has what looks like a chain of three large craters near the terminator, visible in a low power telescope. The terminator is the line between day and night. Before the full moon, it’s the sunrise line. On closer inspection, these craters are of different ages. The north crater Theophilus, 63 miles in diameter and one of my favorite craters with a prominent central peak, looks relatively fresh. It’s not, it’s somewhat older than a billion years. The crater just south or below-left of it is Cyrillus, about the same size, which is almost 4 billion years old. Theophilus slightly overlaps Cyrillus. A bit farther south is Catharina, which again is about the same size and age range as Cyrillus, but seems more broken down than the other.

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 two days before first quarter seen tonight at 10 PM, May 13th 2024. The green ellipse highlights the craters Theophilus, Cyrillus and Catharina which should be easily spotted perhaps even in binoculars. Created using Stellarium, LibreOffice Draw, and GIMP.

The craters Theophilus, Cyrillus and Catharina close up from the Virtual Moon Atlas, rotated to match the image above.

Ephemeris Extra; 5/11/2024, 9 PM EDT Aurora alert for the 13th

Last night in our area there was an incredibly bright display of the Northern Lights or Aurora Borealis. It was cloudy where I was, although my granddaughter was able to get photographs of it with her smartphone. That was the result of an X type flare on the Sun on the 8th resulting in a coronal mass ejection or CME, which arrived here on Earth two days later.

Earlier today there was another X type flare on the Sun. So we expect on Monday the 13th to have another possibility of seeing an aurora. Auroras occur during geomagnetic storms caused by the Earth being intercepted by one of these CME’s. Check spaceweather.com for any news of auroras and check the Current Auroral Oval image. Click on it to get the forecast of the possibility of seeing an aurora in your area. It is from the NOAA Space Weather Prediction Center. If the oval covers your location, and it’s night, or is close, check the sky.

One of the images Nicole Farrell sent me via Messenger. The actual image is much sharper.

Ephemeris: 05/10/2024 – Earthshine

This is Ephemeris for Friday, May 10th. Today the Sun will be up for 14 hours and 39 minutes, setting at 8:59, and it will rise tomorrow at 6:18. The Moon, 3 days past new, will set at 12:37 tomorrow morning.

The Moon tonight will appear as a thin sliver, with not much visible on the thin illuminated portion. However, if as you look at the moon tonight you have the funny feeling that the whole moon is visible, you are right. It’s easily confirmed with a pair of binoculars or a small telescope. What is illuminating the dark part of the Moon is earthshine. The Earth is big and bright in the Moon’s sky, and a fat waning gibbous from its vantage point. From the Moon the Earth has the opposite phase that we see of the Moon from the Earth. The effect used to be called by the term “Old moon in the new moon’s arms”. The effect was first explained by Leonardo da Vinci some 500 years ago. The effect will disappear in a few days as the Moon gets brighter and the Earth less so in the Moon’s sky. Earthshine will appear again when the Moon appears as a waning crescent in the morning. But not many of us are up to see it at that hour.

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 waxing crescent Moon with earthshine and Venus in this undated photograph found on timeanddate.com.

Ephemeris: 05/09/2024 – How the Great Bear got her long tail

This is Ephemeris for Thursday, May 9th. Today the Sun will be up for 14 hours and 37 minutes, setting at 8:58, and it will rise tomorrow at 6:19. The Moon, 2 days past new, will set at 11:30 this evening.

As we see the Great Bear, Ursa Major in the sky with the Big Dipper as its hind end and tail, it seems apparent that the bear is unusual, because bears don’t have long tails. The peoples of the old world, Greeks and others, had a story of how the bear got his long tail. The God Zeus was responsible for the predicament that caused a young lady to be turned into the bear and placed her in the sky out of harm. Some question how he did this. To throw her into the sky, he probably didn’t want to grab the end with the teeth, so he grabbed the bear’s stubby tail whirled the bear around his head and threw her up into the sky where we see her today. Of course the tail was stretched. Some Native Americans did see a bear here too. But the three stars of the dipper’s handle were 3 hunters following the bear.

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 three frame animation showing the stars of the Big Dipper and Ursa Major (Great Bear), constellation lines and constellation art, from Stellarium. Looking overhead at 10 pm, May 9th.

For the story of why the young lady, Callisto, was turned into a bear, check out this post of a week ago: https://bobmoler.wordpress.com/2024/05/02/…

Ephemeris: 05/08/2024 – Saturn comes tottering into the morning twilight

This is Ephemeris for Wednesday, May 8th. Today the Sun will be up for 14 hours and 34 minutes, setting at 8:56, and it will rise tomorrow at 6:21. The Moon, 1 day past new, will set at 10:12 this evening.

Let’s find out where the naked-eye planets have wandered off to this week, and see what planets are left. Jupiter now is too close to the direction of the Sun to be seen. It will move to be in conjunction with the Sun on the 18th of this month and by late June may be visible in the morning sky in twilight. By 5:30 tomorrow morning, about 40 minutes before sunrise, Saturn will be low in the east-southeast and Mars will be lower yet in the east. In telescopes, Saturn will look fairly different this year and next with its rings nearly edge on to us. They will open up a bit through October before closing again. We won’t see the rings go exactly edge on because Saturn will be too close to the Sun in the sky on March 23rd next year. After that the rings will open up again.

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

You may wonder why I use the word tottering in title. The planet Saturn is named after the Roman god of old age, probably because it takes nearly 30 years to orbit the Sun. Even though it’s moving away from twilight faster than Mars is, it’s just the fact that the Sun and Mars are moving faster to the east than it is, leaving him in the dust, so to speak.

Looking to the east-southeast at 5:30 in the morning, less than an hour before sunrise, Saturn and Mars will be visible very low in the sky. Click or tap on the image to enlarge it. Created using Stellarium.

A telescopic view of Saturn. It’s a bit larger than I normally show it when we look at several planets, to show you the rings which are tilted a little less than 3° to our line of sight. Saturn appears 16.4″ diameter, while it’s rings are 38.2″ in extent. 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 tonight, May 8th 2024. The night ends on the left with sunrise tomorrow morning on the 9th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.

Ephemeris: 05/07/2024 – Coma Berenices, a queen’s sacrifice

This is Ephemeris for Tuesday, May 7th. Today the Sun will be up for 14 hours and 32 minutes, setting at 8:55, and it will rise tomorrow at 6:22. The Moon is new today, and won’t be visible.

High in the south-southeast at 10:30 p.m. is a tiny and faint constellation of Coma Berenices, or Berenice’s Hair. In it are lots of faint stars arrayed to look like several strands of hair to the naked eye. The whole group will fit in the field of a pair of binoculars, which will also show many more stars. The story behind it was that Berenice was a real queen of Egypt, whose husband, the Pharaoh Ptolemy III, was away at war. This was in the days when the Greeks ruled Egypt after Alexander had conquered it. She offered her golden tresses to the gods for the king’s safe return. The hair, was placed in a temple. However, the offering disappeared when the king returned. Ever since then, the constellation of Coma Berenices has been seen to commemorate the queen’s sacrifice.

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

Coma Berenices finder chart for early May. Created using Stellarium.

Approximate 7 power binocular field of view (FOV) of the Coma Berenices Cluster. Created using Cartes du Ciel (Sky Charts).

Do not confuse the Coma Berenices star cluster (Melotte 111 and Collinder 256) with the Coma Cluster (actually a supercluster of galaxies up to 300 million light years away) in the northern part of the constellation. The Coma Cluster contains upwards of 10,000 galaxies.

Ephemeris: 05/06/2024 – The star Arcturus: Not from around here

This is Ephemeris for Monday, May 6th. Today the Sun will be up for 14 hours and 29 minutes, setting at 8:54, and it will rise tomorrow at 6:23. The Moon, 1 day before new, will rise at 5:53 tomorrow morning.

Arcturus, a red giant star in the constellation of Boötes the herdsman, is about two thirds the way up the sky in the east-southeast at 10 pm. It’s one of the earliest stars to appear in twilight, being nearly tied in brightness with Vega, a white star low in the northeast. A pointer to Arcturus is the handle of the Big Dipper, following the arc of the handle to Arcturus. Though only 37 light years away, it’s not from around here. It’s passing through the galactic disk from north to south. Arcturus is about 7 billion years old, and is about 8% more massive than our Sun. It appears to be starting its red giant phase, after running out of hydrogen to fuse into helium in its core, and is beginning to fuse the helium. It’s 25 times the size of the Sun and 170 times brighter, and a preview of our Sun when it gets that old.

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 finder chart for the star Arcturus with the Big Dipper part of Ursa Major and Boötes: first showing the stars without the constellation lines and labels, second, showing constellation lines and labels. finally, adding red tracks showing a stars movement over 10,000 years. Arcturus has the greatest motion of any of the stars on this chart. Created using Cartes du Ciel (Sky Charts), LibreOffice Draw, and GIMP.

An H-R* Diagram showing how the Sun’s brightness and temperature will change over its lifetime. Credit: Sloan Digital Sky Survey.

* Hertzsprung-Russell Diagram of a star’s surface (photosphere) temperature vs luminosity. The Main Sequence is where a star lives when it is burning hydrogen, and spends most of its life.

Ephemeris: 05/03/2024 – GTAS meeting tonight: Eclipse Tales

This is Ephemeris for Friday, May 3rd. Today the Sun will be up for 14 hours and 21 minutes, setting at 8:50, and it will rise tomorrow at 6:27. The Moon, 2 days past last quarter, will rise at 4:48 tomorrow morning.

The Grand Traverse Astronomical Society will meet this evening at 8:00 PM at the NMC’s Joseph Rogers observatory which is on Birmley Road, south of Traverse City. The program will consist of returning members from the total solar eclipse last month showing their photographs, and recounting their adventures of going down to the path of totality. And in my case a video of the changes in the sky at totality, as the Moon’s shadow passed over us. Afterward, if it’s clear, will be viewing the skies, though there will be no planets or the Moon out. In the morning hours before dawn tomorrow and Sunday morning there will be a meteor shower, the Eta Aquariid meteor shower of particles from Halley’s Comet striking the Earth’s atmosphere.

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

Totality is weird. The Sun is still overexposed with its corona. The light bar running through it is simply in the camera. The light pole lamp that the camera is parked under is lit. Since we’re looking up the eclipse path, the trailing edge of the Moon’s shadow is now visible approaching with its twilight colors at the edge.

There will be more photos and stories at the meeting.

Ephemeris: 05/02/2024 – All about the constellation of Boötes and Ursa Major

This is Ephemeris for Thursday, May 2nd. Today the Sun will be up for 14 hours and 19 minutes, setting at 8:49, and it will rise tomorrow at 6:29. The Moon, 1 day past last quarter, will rise at 4:27 tomorrow morning.

Seen in the east at 10:30 p.m. tonight is the kite shaped constellation of Boötes the herdsman. The bright star Arcturus is at the bottom of the kite to the right. It is pointed to by the arc of the handle of the Big Dipper, higher in the east. 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 Zeus intervened and placed them both in the sky to save her, as 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

A finder chart for the constellation of Boötes and Ursa Major, animated to show the stars without labels or lines, then the constellation lines and the star Arcturus labeled, and then the art that comes with Stellarium. Created using Stellarium and GIMP.

Arcas about to slay the bear, when in the upper left Zeus places them in the heavens. By the 17th century artist Baur. Source: University of Virginia Electronic Text Center