Archive
Ephemeris: 05/17/2024 – The famous Big Dipper stars Mizar and Alcor
This is Ephemeris for Friday, May 17th. Today the Sun will be up for 14 hours and 55 minutes, setting at 9:07, and it will rise tomorrow at 6:10. The Moon, 2 days past first quarter, will set at 4:01 tomorrow morning.
In tonight’s sky, the Big Dipper is nearly overhead. In its handle is a star or two that are interesting. It’s the star at the bend in the handle. It’s called Mizar. Next to it, for those with good eyesight, is a dimmer star, called Alcor. The name Mizar is from the Arabic, meaning apron or cover, while Alcor means the forgotten one. Before optometrists, the ability to actually see both stars was a test for good eyesight, especially for Arabic warriors. The pair is also known as the “Horse and the Rider”. I’ve been told that some Native American tribes saw the handle stars as hunters following the Great Bear, Ursa Major, of which the Big Dipper is a part, rather than its very unnatural tail. Dim Alcor became a hunting dog.
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: 05/15/2024 – Getting reacquainted with the Moon
This is Ephemeris for Thursday, May 16th. Today the Sun will be up for 14 hours and 53 minutes, setting at 9:06, and it will rise tomorrow at 6:11. The Moon, 1 day past first quarter, will set at 3:45 tomorrow morning.
My interest in astronomy has always tended to be in deep sky, that is the part of astronomy having to do with objects beyond the solar system. This was probably mainly due to the fact that my first telescope was the reflecting telescope and not really that good at viewing the planets. My opinion of the Moon has normally been that of being a big streetlight that kept me from viewing the faint things in the sky. However, as the Apollo program was ramping up in the 1960s, I began to get more interested in the Moon. And so it is, again, now that the Artemis program is beginning to ramp up. Unfortunately the landing zones that are being planned are at the South Pole of the Moon, which we can barely see from the Earth.
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: 05/15/2024 – Where have naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, May 15th. Today the Sun will be up for 14 hours and 51 minutes, setting at 9:05, and it will rise tomorrow at 6:12. The Moon, at first quarter today, will set at 3:28 tomorrow morning.
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 Saturday 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 still 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
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
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
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.
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
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
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.
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
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.
Bob Moler's Ephemeris Blog 