Archive
01/31/2022 – Ephemeris – The winter circle of bright stars
This is Ephemeris for Monday, January 31st. Today the Sun will be up for 9 hours and 47 minutes, setting at 5:50, and it will rise tomorrow at 8:01. The Moon, 1 day before new, will rise at 8:48 tomorrow morning.
The winter skies are blessed with more first magnitude stars than any other season. Six of these stars lie in a large circle centered on the seventh, It’s called the Winter Circle. This circle is up in the evening. Starting high overhead is yellow Capella in Auriga the charioteer. Moving down clockwise is orange Aldebaran in the face of Taurus the Bull. Then down to Orion’s knee, we find blue-white Rigel. Down and left is the brightest star of all the brilliant white Sirius the Dog Star in Canis Major, lowest of these stars in the south-southeast. Moving up and left is white Procyon in Canis Minor, Above Procyon is Pollux in Gemini, the twins. All these are not quite centered on Betelgeuse, the bright red star in Orion’s shoulder.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.
Addendum
The bright stars of winter arrayed in a not so accurate circle. Some call it the Winter Hexagon. These stars are what make the winter sky so brilliant on the rare clear night in winter. Created using Stellarium.
03/09/2021 – Ephemeris – A celestial warning to keep off thin ice
This is Ephemeris for Tuesday, March 9th. Today the Sun will be up for 11 hours and 35 minutes, setting at 6:41, and it will rise tomorrow at 7:03. The Moon, halfway from last quarter to new, will rise at 6:12 tomorrow morning.
The native Anishinaabe peoples of the Great Lakes Region, which includes the tribes of our area, have one constellation of winter I know of. It is The Wintermaker which uses many of Orion’s stars and whose arms stretch from Aldebaran in Taurus the bull to Procyon the Little Dog Star, embracing the whole of the winter sky. Now that spring is nearly here he is sinking into the west, losing to the heat of the Sun. The first constellation of spring is Curly Tail, or the Great Underwater Panther. It uses the stars of Leo the lion’s backward question mark as its curly tail and the small knot of stars that are the head of Hydra the water snake below Cancer the crab as its head. His warning: Keep off the thinning ice or break through and be snatched by the great panther that lives below.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Great Underwater Panther finder animation. Three frame animation of Unannotated sky, International Astronomical Union constellations, and Anishinaabe (Ojibwe) constellations of Curly Tail and Wintermaker. Click on the image to enlarge. Created using Stellarium and GIMP. Additional credits below.
The time is set for the above image is 10 pm on March 9th.
The constellation art is part of the latest versions of Stellarium. Ojibwe (Anishinaabe) constellation art by Annette S Lee and William Wilson from Ojibwe Sky Star Map Constellation Guide, ISBN 978-0-615-98678-4. There is also an Ojibwe Sky Star Map poster suitable for framing.
12/15/2020 – Ephemeris – Hyades, the face of Taurus the bull
This is Ephemeris for Tuesday, December 15th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:02, and it will rise tomorrow at 8:14. The Moon, 1 day past new, will set at 6:03 this evening.
The face of the constellation Taurus the bull looks like the letter V sideways above the rising Orion the Hunter in the east at 9 p.m. The bright star at the tip of a letter V of stars is Aldebaran. Look with binoculars at the letter V shape and you will see the stars of the Hyades star cluster The Hyades is the closest star cluster to us, at about 153 light years. And is important for that reason. Before satellites like Hipparcos and Gaia the Hyades was the only star cluster that could be directly measured by a technique called parallax, using the radius of the Earth’s orbit as one side of a surveyors enormous triangle. Its many stars at the same distance were used to determine distances of star clusters even farther away. Additional techniques based on the distance of the Hyades allowed us to measure distances to the nearest galaxies.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aldebaran in the ‘V’ shape of the Hyades (The face of Taurus the bull) with the Pleiades above. Aldebaran is not part of the Hyades, being about halfway between us and the cluster. Created using Stellarium.
HR diagram showing the Hyades and Pleiades. Credit: European Southern Observatory.
The Hertzsprung–Russell diagram or HR diagram is one of the great astronomical tools developed in the early 20th century by plotting stars by surface temperature horizontally (hot to cool, left to right) and brightness vertically. It turns out that stars in the prime of life and shining via converting hydrogen to helium lie on a diagonal line from hot and bright from the upper left to cool and dim to the lower right. The line is called the main sequence. In plotting the Hyades stars against other star cluster stars the vertical displacement of the main sequence line is a function of the relative distances of the two star clusters from us. This is just one of the uses of the HR diagram.
12/08/2020 – Ephemeris – Finding Taurus the bull
This is Ephemeris for Tuesday, December 8th. Today the Sun will be up for 8 hours and 54 minutes, setting at 5:02, and it will rise tomorrow at 8:08. The Moon, 1 day past last quarter, will rise at 1:39 tomorrow morning.
Orion is the big splashy constellation in the east southeast by 9 in the evening. Above it is another famous constellation Taurus the bull. Its face is a letter V shape of stars on its side with the open end of the V to the left. The bright star at the lower left end of the sideways V is the ruddy star Aldebaran, the Bull’s angry bloodshot eye. The bull is charging down at Orion. The Pleiades, also known as the seven sisters, is the cluster of stars in his shoulder, above the V. The stars in the face of Taurus, except for Aldebaran belong to a star cluster like the Pleiades, but closer and older, called the Hyades. In Greek mythology the Hyades are half sisters to the Pleiades, all fathered by the god Atlas.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Three views of Taurus the bull and Orion the hunter for 9 p.m. on December 8th. Created using Stellarium and GIMP.
The Pleiades (right) and the Hyades (left) in this photograph I took January 4, 2016. The orientation is a bit different from how it appears in early December.
12/17/2019 – Ephemeris – Hyades, the face of Taurus the Bull
Ephemeris for Tuesday, December 17th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:03, and it will rise tomorrow at 8:15. The Moon, 2 days before last quarter, will rise at 11:14 this evening.
The face of the constellation Taurus the bull looks like the letter V sideways above the rising Orion the Hunter in the east at 9 p.m. The bright star at the tip of a letter V of stars is Aldebaran. Look with binoculars at the letter V shape and you will see the stars of the Hyades star cluster The Hyades is the closest star cluster to us, at about 153 light years. And is important for that reason. Before satellites like Hipparcos and Gaia. The Hyades was the only star cluster to be directly measured by a technique called parallax, using the radius of the Earth’s orbit as one side of a surveyors enormous triangle. Its many stars at the same distance were used to determine distances of star clusters even farther away. Additional techniques based on the distance of the Hyades allowed us to measure distances to the galaxies.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aldebaran in the ‘V’ shape of the Hyades (The face of Taurus the bull) with the Pleiades above. Created using Stellarium.
01/24/2019 – Ephemeris – Taurus the bull
Ephemeris for Thursday, January 24th. Today the Sun will be up for 9 hours and 29 minutes, setting at 5:40, and it will rise tomorrow at 8:09. The Moon, half way from full to last quarter, will rise at 10:14 this evening.
Midway up the sky in the southeast at 8 p.m. is the constellation of the giant hunter Orion. Above him, to the right is Taurus the bull. His face is a letter V shape of stars lying on its side, the star cluster Hyades, with the bright orange-red star Aldebaran at one tip of the V as its angry blood-shot eye, but actually about half way between us and the cluster. Orion is depicted in the sky facing, with club in one hand and a shield in the other, the charging Taurus. The Pleiades star cluster is in his shoulder. Taurus in Greek mythology was the form the god Zeus when he carried off the maiden Europa. Europa’s still with him as the intriguing satellite orbiting Zeus’ Roman equivalent the planet Jupiter.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Taurus and Europa at 8 p.m. January 24, 2019. Created using Stellarium.
The Rape of Europa by Titian. According to the story Zeus as a bull abducted Europa and swam to Crete, where she became the first queen of that island, and bore him three sons. Other paintings of this subject are by Rembrandt and de Troy. This painting belongs to the Isabella Stewart Gardener Museum in Boston, MA. Click on the image to enlarge.
Jupiter’s satellite Europa, slightly smaller than the Earth’s moon, has a fresh ice surface with very little cratering. The ice floats on a deep water ocean supposedly containing more water than all the Earth’s oceans. Click on the image to enlarge. This is a place NASA will send a spacecraft to look for the chemistry of life. Credit NASA/JPL, Ted Stryk.
11/23/2018 – Ephemeris – The Moon and Aldebaran
Ephemeris for Friday, November 23rd. The Sun will rise at 7:50. It’ll be up for 9 hours and 17 minutes, setting at 5:07. The Moon, at full today, will rise at 5:55 this evening.
Tonight’s full Moon will be accompanied by the bright star Aldebaran, the angry red eye of the constellation Taurus the Bull. Earlier this year we had the last of nearly two years of the Moon every month passing in front of Aldebaran. The tilt of the Moon’s orbit with respect to the Earth’s own orbit of the Sun slides slowly westward with time, so The Moon won’t pass in front of Aldebaran for those of us on Earth again until 2033. This sliding of the Moon’s orbit is called regression of the nodes. A node is where the Moon’s orbital plane crosses the Earth’s. These are places eclipses of the Sun and Moon occur if lined up with the full or new moons. Why regression? The nodal points are moving westward, backward of most motions in the solar system.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
11/12/2018 – Ephemeris – Orion is rising
Ephemeris for Veterans Day Observed, Monday, November 12th. The Sun will rise at 7:35. It’ll be up for 9 hours and 41 minutes, setting at 5:17. The Moon, 3 days before first quarter, will set at 9:25 this evening.
Just after the Moon sets tonight winter’s most dazzling constellation will be rising, Orion the hunter of Greek myth. The stars of his torso are in a rectangle leaning to the left. Orion’s belt of three stars in a straight line in the center of the rectangle is nearly vertical. The Anishinaabe peoples whose region we live in see the constellation of the Wintermaker rather than Orion. It uses Orion’s torso and belt stars, but his arms are spread wide from Aldebaran in the face of Taurus the bull to the west to Procyon in Canis Minor, which won’t rise until 11 p.m. to the east. The Wintermaker’s arms are wide enough to embrace the entire winter sky. Its name in Anishinaabemowin, which is Biboonikeonini, means “North Wind”.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Ephemeris Extra – Occultation of Aldebaran visible from the Upper Peninsula and the tip of northern lower Michigan
In the early morning hours of July 10th the very northern part of the IPR listening area will have a chance to see the last occultation of the bright star Aldebaran for at last 15 years. An occultation is where the Moon in this case passes in front of or occults a planet or a star. In astronomy occult means to hide. The event is an occultation. There is no black magic involved. It will be a grazing event, with Aldebaran popping in and out of view at the mountains and valleys at the southern edge of the Moon along a line running south of Mackinaw City and across the eastern tip of the Upper Peninsula.
The Straits of Mackinac area showing the green southern graze line of the Occultation of Aldebaran. Credit Map Google Earth, Graze line by Occult 4.
It’s a clear miss for the Interlochen area, with the star skirting the Moon at it’s 5 o’clock position. The time of the event will be near 4:38 a.m. with the maximum time of the event increasing from west to east at nearly 2,000 miles an hour. At that time the Moon and Aldebaran will be low in the east-northeast and only 7 degrees above the horizon.
Location of the Moon and Aldebaran in the sky at 4:38 a.m. July 10, 2018 from the Interlochen/Traverse City area.
More information on this occultation from Sky and Telescope is here.
This will be the last occultation of Aldebaran visible from around here for the next 15 years. However starting in 5 years there will be a monthly series of occultations of the bright star Regulus, and the next year a series of occultations of the star Spica will begin. That’s just for the Moon with bright stars. The Moon occults many dimmer stars a month. A very important field of occultations is the observation of occultations of asteroids and Kuiper belt objects to discover their size, shape, any satellites and whether they have rings. Go to the International Occultation Timing Association https://occultations.org for more information.
Hat tip to Jerry Dobek, Director of the Joseph H. Rogers Observatory
04/24/2018 – Ephemeris – Venus will be south of the Pleiades tonight
Ephemeris for Tuesday, April 24th. The Sun rises at 6:43. It’ll be up for 13 hours and 55 minutes, setting at 8:39. The Moon, 2 days past first quarter, will set at 4:51 tomorrow morning.
Tonight the brilliant planet Venus will be just south of the Pleiades, also known as the Seven Sisters star cluster. From our cockeyed position on the Earth about half way from the equator and the North Pole. The sky in the east and west, low in the sky, is tilted about the same angle, namely about 45 degrees. If you’re listening to this program from other than Northern Michigan the angle will be the same as your latitude. So instead of south being down, as one would expect when looking to the south, south is to the lower left when looking to the west. On this program Thursday, Friday and Monday I’ll be talking about Venus and what the ancients found out about the planet in the days before the telescope was invented.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus, Pleiades, Aldebaran with the Hyades star cluster and Orion are seen in the west at 9:45 p.m. April 24, 2018. Venus is south of the Pleiades. Created using Stellarium.
A closer look at Venus and the Pleiades with the coordinate grid added. The lines that run from upper right to lower left are lines of right ascension, analogous to longitude lines on the Earth. To the upper right is north and lower left is south. The other lines are those of declination. Like latitude lines on the Earth, they run east and west. Created using Stellarium.
Bob Moler's Ephemeris Blog 