Archive
01/04/2016 – Ephemeris – Some named stars in Orion and how to remember them
Ephemeris for Monday, January 4th. The Sun will rise at 8:20. It’ll be up for 8 hours and 55 minutes, setting at 5:15. The Moon, 2 days past last quarter, will rise at 3:49 tomorrow morning
Now that the Moon has fled let’s turn to the dark skies of winter and the magnificent constellation of Orion the hunter. At 9 p.m. he’s not yet completely upright in the southeast at 9 p.m. His seven bright stars make him easy to spot, starting with his belt of three stars in a straight line angling down to the left. It is inside a rectangle framing his shoulders and knees, leaning now to the left. The bright reddish star at the upper left corner is Betelgeuse, which according to a certain movie one shouldn’t say three-time in a row. The other shoulder star is a name familiar to Harry Potter fans, Bellatrix, though there’s nothing Lestrange about it. The lower right star is the bright blue-white Rigel. All in all a very impressive constellation.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Some of Orion’s star names. Orion at 9 p.m. January 4, 2016. Created using Stellarium.
12/10/2015 – Ephemeris – What’s a charioteer doing holding goats?
Ephemeris for Thursday, December 10th. The Sun will rise at 8:08. It’ll be up for 8 hours and 53 minutes, setting at 5:02. The Moon, 1 day before new, will rise at 7:59 tomorrow morning.
Rising now more than half way up the sky in the east at 9 p.m. will be the bright star Capella and its pentagonal constellation Auriga the Charioteer. Auriga appears to be hunched down sideways in the sky in his chariot carrying 4 goats. Capella is the mother goat, and a slim triangle of stars near her are her kids. Perhaps the kids in the chariot were such a distraction that he crashed. So maybe the gods placed them in the sky as a warning. In fact that triangle is an asterism widely known as the Kids. The Milky Way runs through Auriga and it is the home of several star clusters that appear as fuzzy spots in binoculars. Capella for us in northern Michigan never sets. It is a winter star that can be seen year round. It’s disconcerting to spot it scraping the northern horizon in July.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Auriga and neighboring constellations for 9 p.m. December 10, 2015. Created using Stellarium and GIMP.
12/08/2015 – Ephemeris – The hard charging Taurus the bull
Ephemeris for Tuesday, December 8th. The Sun will rise at 8:07. It’ll be up for 8 hours and 55 minutes, setting at 5:02. The Moon, 3 days before new, will rise at 6:03 tomorrow morning.
Low in the east 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 left tip of the V as its angry blood-shot eye. Orion is depicted in the sky facing 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 orbiting Zeus’ Roman equivalent Jupiter. In fact the moons around the planet Jupiter are generally named for Jupiter’s lovers and friends. His wife is missing from the entourage, and will be until the NASA spacecraft Juno reaches Jupiter next year.
Times 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 8, 2015. Created using Stellarium and GIMP.
11/30/2015 – Ephemeris – Orion Rising
Ephemeris for Monday, November 30th. The Sun will rise at 7:58. It’ll be up for 9 hours and 5 minutes, setting at 5:04. The Moon, 3 days before last quarter, will rise at 10:12 this evening.
We have a few hours of darkness tonight before the Moon comes up. In the east the central winter constellation Orion the hunter throws a leg over the horizon between 8 and 9 p.m. as Robert Frost told in his poem Star-Splitter. The upright rectangle that is his body on January evenings is tilted to the left as he rises, with bright red star Betelgeuse at the top left of the rectangle, his shoulder. At the opposite corner is blue-white Rigel, a knee. In the center of the rectangle is a line of three stars nearly vertically aligned, which represents Orion’s belt. Above Orion is another bright orange star at one end of a letter V shape of stars. That’s Aldebaran the angry eye in the face if Taurus the bull who apparently is none to happy with Orion.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion Rising at 8:30 p.m. (3 1/2 hours after sunset) on November 30th. Created using Stellarium.
02/16/2015 – Ephemeris – The Winter Circle
Feb 16. This is Bob Moler with Ephemeris for President’s Day, Monday, February 16th. The sun will rise at 7:42. It’ll be up for 10 hours and 30 minutes, setting at 6:12. The moon, 2 days before new, will rise at 6:25 tomorrow morning.
The winter skies are blessed with more first magnitude stars than any other season. That’s a full one-third of the total are seen is a relatively small area. Six of these stars lie in a large circle centered on the seventh. This circle is up at 9 p.m. Starting high overhead is Capella in Auriga the charioteer. Moving down clockwise is Aldebaran in the face of Taurus the Bull. Then down to Orion’s knee we find Rigel. Down and left is the brightest star of all Sirius the Dog Star in Canis Major, lowest of these stars in the south-southeast. Moving up and left is Procyon in Canis Minor, Above Procyon is Pollux in Gemini the twins. All these are centered on Betelgeuse the bright red star in Orion’s shoulder.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Winter Circle of 1st magnitude stars
02/12/2015 – Ephemeris – The brilliant blue star in Orion: Rigel
Ephemeris for Thursday, February 12th. The sun will rise at 7:47. It’ll be up for 10 hours and 18 minutes, setting at 6:06. The moon, 1 day past last quarter, will rise at 2:52 tomorrow morning.
Two days ago I talked about the star Betelgeuse the bright red star in the top left of Orion’s upright rectangle. Orion is seen in the south at 9 in the evening. The blue-white star in Orion’s opposite corner is usually brighter. It is Rigel whose longer Arabic name of which Rigel is the first part means Left Leg of the Giant. Rigel is a giant itself, actually a super giant star, which is more a measure of its mass than its size, that of 21 solar masses. Its surface temperature is more than twice as hot as the sun. It is 120 thousand times as bright as the sun and 78 times its diameter. Its distance is around 860 light years. Those with telescopes might be able to spot a close companion star to Rigel, just at the edge of the bright arc light image of Rigel itself.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion upright and due south. Created using Stellarium.
Rigel with its companion star as photographed through a telescope. No attribution. Source: http://washedoutastronomy.com/content/urban-orion?page=1
02/10/2015 – Ephemeris – Orion’s bright red star, Betelgeuse
Ephemeris for Tuesday, February 10th. The sun will rise at 7:50. It’ll be up for 10 hours and 13 minutes, setting at 6:03. The moon, 1 day before last quarter, will rise at 12:51 tomorrow morning.
The bright red star in constellation Orion’s shoulder is Betelgeuse, and its now thought to be about 640 light years away give or take a couple of hundred light years*. The name Betelgeuse means “Armpit of the central one” in Arabic. Orion is seen in the south at 9 in the evening. Even at Betelgeuse’ great distance it’s the star whose surface is easiest seen, after the sun of course. That’s because it’s so big. As large around as the size of the orbit of Jupiter. Betelgeuse is losing mass in a huge cloud around it. It is a massive star in the late stages of its life even though it’s only 7 million years old. Some astronomers speculate that it will explode in a massive supernova within the next million years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Update
* I’m being a bit facetious here. See the addendum, and also by coincidence a post from EarthSky today How far is Betelgeuse?
Addendum
Orion upright and due south. Created using Stellarium.
Our estimates of the size, mass and luminosity of Betelgeuse depend on knowing its distance. The distance is not well-known because Betelgeuse is a single star, it is not a binary for which can be applied Newton’s laws to calculate these values. Therefore these values in the broadcast program, where I have 59 seconds total, appear more certain than they really are. Wait for Thursday’s program when I cover Rigel and see how close the values are between the two. But Rigel appears to be a different star altogether. Somebody’s wrong.
“This artist’s impression shows the supergiant star Betelgeuse as it was revealed thanks to different state-of-the-art techniques on ESO’s Very Large Telescope, which allowed two independent teams of astronomers to obtain the sharpest ever views of the supergiant star Betelgeuse. They show that the star has a vast plume of gas almost as large as our Solar System and a gigantic bubble boiling on its surface. These discoveries provide important clues to help explain how these mammoths shed material at such a tremendous rate. The scale in units of the radius of Betelgeuse as well as a comparison with the Solar System is also provided.” Credit: ESO/L. Calçada (ESO is the European Southern Observatory)
01/16/2015 – Ephemeris – Orion’s greater hunting dog: Canis Major
Ephemeris for Friday, January 16th. The sun will rise at 8:16. It’ll be up for 9 hours and 13 minutes, setting at 5:29. The moon, 3 days past last quarter, will rise at 5:09 tomorrow morning.
The great winter constellation or star group Orion the Hunter, is located in the south-southeastern sky at 9 p.m. His elongated rectangle of a torso is almost vertical. In the center of the rectangle are three stars in a line that make his belt. As a hunter, especially one of old, he has two hunting dogs. The larger, Canis Major can be found by following the three belt stars of Orion down and to the left. There lies the brilliant star called Sirius, also known as the Dog Star. It’s in the heart of a stick figure dog low in the southeast facing Orion that appears to be begging. I’ll have more to say about Sirius on Monday, but there’s a fine star cluster, caller M41, at the 5 o’clock position from Sirius easily visible in binoculars or a small telescope.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion and his hunting dogs with pointers as seen at 9 p.m. in the second half of January. Created using Stellarium.
01/12/2015 – Ephemeris – The world’s faorite constellation: Orion
Ephemeris for Monday, January 12th. The sun will rise at 8:18. It’ll be up for 9 hours and 6 minutes, setting at 5:24. The moon, 1 day before last quarter, will rise at 1:02 tomorrow morning.
For people the world over who look up and recognize the brighter constellations Orion is perhaps the odd on favorite. The Big Dipper, a favorite in the northern hemisphere, cannot be easily seen south of the equator. The Southern Cross cannot be easily be seen north of the equator. Orion, or parts of him can be seen from pole to pole because he straddles the equator of the sky. It has 7 bright stars like the Big Dipper, but those seven are brighter than those in the big Dipper. In the early evening Orion is seen is the southeast. The three stars of his belt now tipped diagonally from upper right to lower left. They are in the center of a left leaning rectangle of stars with bright red Betelgeuse to the upper left and bright blue-white Rigel to the lower right.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion from mid latitudes north of the equator. Orion would be upside down if viewed south of the equator. Created using Stellarium.
Orion from near the north pole. Created using Stellarium.
Orion from near the south pole. Created using Stellarium.
12/15/2014 – Ephemeris – How to find Orion through the evening
Ephemeris for Monday, 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, 1 day past last quarter, will rise at 2:15 tomorrow morning.
At 7 p.m. tonight the great central constellation of winter Orion is struggling to rise, with the top half of him in the eastern sky. By 9 p.m. he’s whole and low in the east-southeast. By midnight he has taken his rightful place as the central winter constellation. In the evening now his distinctive belt of three stars in a straight line, by which most folks can find him, is more or less vertical in the sky. His brightest stars are Betelgeuse a red star to the left of the belt and blue-white Rigel to the right. When Orion’s the highest in the south we’ll explore the wonders within this constellation, the most famous constellation world over. Parts of it can be seen at the north and south poles of the Earth. The Big Dipper, which isn’t a real constellation, doesn’t hold a candle to it.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion rising at 7 p.m. December 15, 2014. Created using Stellarium.
Orion rising higher at 9 p.m. December 15, 2014. Created using Stellarium.
Orion close to the meridian at 12 midnight, December 16, 2014. There is distortion in this projection. Orion is standing straighter in the real sky than shown here. Created using Stellarium.
Bob Moler's Ephemeris Blog 