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Posts Tagged ‘Aldebaran’

11/12/2018 – Ephemeris – Orion is rising

November 12, 2018 Comments off

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.

Orion or Wintermaker rising
Take your pick: it’s either Orion rising of the Wintermaker rising at 9:30 p.m. November 12th. Created using Stellarium and GIMP, and Western and Ojibwe star lore.

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Ephemeris Extra – Occultation of Aldebaran visible from the Upper Peninsula and the tip of northern lower Michigan

July 8, 2018 Comments off

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.

Occultation of Aldebaran map

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.

Moon and Aldebaran finder chart

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

April 24, 2018 Comments off

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

The sky low in the west

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.

Venus and the Pleiades with grid

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.

03/22/2018 – Ephemeris – The bright star Aldebaran will appear below the Moon tonight

March 22, 2018 Comments off

Ephemeris for Thursday, March 22nd. The Sun will rise at 7:42. It’ll be up for 12 hours and 15 minutes, setting at 7:57. The Moon, 2 days before first quarter, will set at 1:48 tomorrow morning.

The bright star Aldebaran will appear below the Moon tonight. Over the past two years we’ve seen the Moon cover Aldebaran in an event called an occultation on several occasions. There will be a similar occultation tonight for the far northern part of the Earth. Though the series of Aldebaran occultations won’t end until September this year, we won’t see any of them. The Next season of monthly Aldebaran occultations for the Earth won’t start until 2033. It will last a bit more than 2 years. We’ll see our share of those occultations then. Other bright, first magnitude, stars that can be occulted by the Moon are Pollux in Gemini, Regulus in Leo, Spica in Virgo and Antares in Scorpius.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The Moon and Aldebaran

The star Aldebaran, the bloodshot eye of Taurus the bull at 9 p.m. tonight, March 22, 2018 to be seen below the crescent Moon. The rest of the face of Taurus, the V-shaped stars of the star cluster called the Hyades will be visible in binoculars. Created using Stellarium. The Moon will be brighter than Aldebaran, not the opposite as seen here.

02/12/2018 – Ephemeris – The Winter Circle

February 12, 2018 Comments off

Ephemeris for Monday, February 12th. The Sun will rise at 7:47. It’ll be up for 10 hours and 19 minutes, setting at 6:07. The Moon, 3 days before new, will rise at 6:29 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 at 9 p.m. 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 centered, well not quite, on Betelgeuse the bright red star in Orion’s shoulder.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Winter Circle

The bright stars of winter arrayed in a circle (well almost). Created using Stellarium.

12/29/2017 – Ephemeris – Last occultation of the star Aldebaran by the Moon is tomorrow night

December 29, 2017 1 comment

Ephemeris for Friday, December 29th. The Sun will rise at 8:19. It’ll be up for 8 hours and 51 minutes, setting at 5:10. The Moon, half way from first quarter to full, will set at 5:08 tomorrow morning.

We have one last cool astronomical event that can be seen from here in 2017. Of course, weather permitting. Tomorrow night the Moon will occult the bright star Aldebaran in Taurus the bull from 6:17 to 7:17 p.m. I’m not dabbling with the black arts here, even though I’m using the Occult 4 program to find it. In astronomy occult is a verb meaning to hide, and the event is called an occultation. The Moon will appear to move in front of, or hide the star Aldebaran. At 6:17 p.m. Aldebaran will disappear at the dark edge of the Moon at its 8 o’clock position. Binoculars will be needed to spot the star against the glare of the bright Moon before the event. Aldebaran will pop out from behind the Moon at a bit above the 3 o’clock position at 7:17 p.m.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Occultation visibility map

Occultation visibility map for the occultation of Aldebaran by the Moon for us in the Unites States, the early evening of December 30, 2017. Created using Occult 4 by IOTA.

Occultation start

Occultation start 6:17 p.m. December 30, 2017. as seen from the Grand Traverse area of Michigan. Actual times may vary depending on your location. Created using Stellarium.

Occultation end

Occultation end 7:17 p.m. December 30, 2017. as seen from the Grand Traverse area of Michigan. Actual times may vary depending on your location. Created using Stellarium.

Note the times are for the Traverse City/Interlochen area. It will vary by a few minutes for northern lower Michigan.  The position angles of the entrance and exit points of Aldebaran will also be different.

Otherwise use a planetarium program like Stellarium to preview the event. However, set the program for topocentric coordinates. In Stellarium that’s in the Configuration window, Tools Tab and check the Topocentric coordinates box. Topocentric coordinates are the apparent positions for your location on the Earth. So also make sure your location is correct. The geocentric conjunction of the two bodies will be December, 31, 0:49.2 UT, so it will occur after midnight on the morning of December 31st for locations in northern Europe and Asia.

Program Note

The January preview will be an Ephemeris Extra post on December 31st.

 

 

12/15/2017 – Ephemeris – Taurus, Bullish on Winter

December 15, 2017 1 comment

Note:  The title of this post I’ve taken from an article I wrote for the December 1999 issue of the Stellar Sentinel, the monthly newsletter of the Grand Traverse Astronomical Society, which I will reprint with some tweaks, as the addendum to this post.  Winter will arrive in six days, though I’m not particularly bullish on it, but it fits the constellation I’m talking about today.

Ephemeris for Friday, December 15th. The Sun will rise at 8:12. It’ll be up for 8 hours and 50 minutes, setting at 5:02. The Moon, 3 days before new, will rise at 6:25 tomorrow morning.

Low in the east-southeast at 9 p.m. is the constellation of Orion the giant hunter. Above him is Taurus the bull. His face is a letter V shape of stars lying on its side with the bright orange-red star Aldebaran at the bottom tip of the V as its angry blood-shot eye. Orion is depicted in the sky facing him with club in one hand and a shield in the other the approaching and in some depictions charging Taurus. The V of stars is a star cluster called the Hyades. The Pleiades are in his shoulder above. Taurus, in Greek mythology, was the guise the god Zeus when he carried off the maiden Europa. Europa’s still with him, sort of, as the intriguing satellite with a buried ocean 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 Orion

Three views of Taurus the bull and Orion the hunter for about  p.m. in December.

Hyades and Pleiades

The Hyades (lower left) and the Pleiades (upper right). My photograph from many years ago BD (Before Digital).

The first constellation of winter to appear is probably a toss-up between Auriga the charioteer and Taurus the Bull. Auriga never quite disappears, or at least Capella its brightest star is circumpolar and never quite sets here in Northern Michigan. But Auriga sneaks up slowly in the northeast. Taurus on the other hand makes a grand entrance on autumn evenings preceded by the Pleiades, the Seven Sisters star cluster.

Taurus’ brightest star is Aldebaran, the bull’s angry bloodshot eye. It is at the left tip of a letter V of stars that is the bull’s face. Above the V are single stars that form the tips of its very long horns. Other stars below form the front legs of this beast. That’s it. Only the front part of the bull appears in the sky. In its shoulder are the Pleiades.

According to Greek mythology Taurus represents the god Zeus, the Roman Jupiter, who, in the disguise of a bull abducted the beautiful maiden Europa. This isn’t the only celestial disguise of Zeus. Cygnus is the disguise of Zeus in the famous Leda and the swan affair.

The Pleiades and the Hyades, the V-shaped star cluster of Taurus’ head also have their places in Greek Mythology. The Hyades and Pleiades are half sisters of each other who share Atlas as their father. But it is the Pleiades which are more prominent and have more stories about them. It is the Pleiades that are pursued by Orion the hunter, the central constellation of winter. And since the Pleiades are west of Orion it does appear that Orion continues to chase them around and around the sky daily. To the Kiowa Indians the Pleiades were also young maidens. As the story goes they were being chased by a large bear. The Great Spirit placed them on what we know today as Devil’s Tower in Wyoming to keep them out of reach of the bear. It is said that even today the sides of this tower show the scars of the bear’s claws. Devil’s Tower was the prominent landmark in the movie Close Encounters of the Third Kind. To the Anishinaabek native peoples around here the Pleiades is the “Hole in the Sky” or the seven sweating stones that are heated for the sweat lodge ceremony.

What do we know about Taurus today? Aldebaran is an orangish giant star which lies at a distance of 65 light years. It doesn’t belong to the Hyades, which is about 151 light years away. Aldebaran’s diameter is 40 times the Sun’s, about the diameter as the orbit of Mercury. It’s only 1.7 times tha mass of the Sun. Aldebaran shines at 153 times the Sun’s output.

Aldebaran appears to be part of the Hyades cluster, but it is less than half the distance to this most important star cluster. Though less prominent as the Pleiades, the Hyades is the most important star cluster in the heavens. The reason is because the Hyades was until recently the only star cluster close enough to get an accurate distance measurement by direct means. That direct means is parallax, measuring the shift of the star’s position in the sky due to the earth’s changing position in orbit of the Sun. The Hipparcos satellite has been refining these parallaxes over the past few years. Its measurement of the distance of the Hyades cluster is 151 light years give or take a bit less than a light year. The Hyades distance is the basis for all more distant measurements to the ends of the known universe.

The Hyades is a good binocular object with over 100 stars visible. The cluster actually overflows the binocular’s field of view. This cluster is also known as the Taurus Moving Cluster because its stars are receding towards a point northeast of Orion’s Betelgeuse.

Of course the splashiest part of Taurus is the Pleiades. For people with good vision 6 or more stars can be seen. I can see 4 or 5 stars and fuzz, which are unresolved stars. Many, who see the Pleiades for the first time, think the tiny pattern of stars is the Little Dipper. The stars do indeed look like a tiny dipper, with a nice bowl and a sawed off handle. And that’s what I call it: the Tiny Dipper. The big surprise of the Hipparcos distance measurements is the distance of the Pleiades. The generally accepted distance was about 410 light years. Hipparcos measured 375 light years. This means that the stars of the Pleiades are somewhat dimmer than believed before. Pleiades prior measurement was based on photometric or brightness measurements with the stars of the Hyades and other stars of the same type and known brightness and distance. So it turns out in the case of the Pleiades that the former measurements weren’t as accurate as thought, and means we have more to understand about stellar evolution as it relates to star brightness. Or perhaps Hipparcos is wrong. And interesting debate and more measurements are sure to follow.

The age of the Pleiades is thought to be around 100 million years, young compared to the Sun’s 4.6 billion years. Long exposure photographs and some telescopes can still spot the remaining wisp’s of the nebulae they were born from. The material is probably dust simply reflecting the light of the stars in the cluster.

Taurus is a great constellation to scan with a pair of binoculars.