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01/23/2014 – Ephemeris – The river Eridanus
Ephemeris for Thursday, January 23rd. The sun will rise at 8:10. It’ll be up for 9 hours and 28 minutes, setting at 5:38. The moon, 1 day before last quarter, will rise at 1:31 tomorrow morning.
There is a long and sinuous constellation that’s part of the winter sky. It is Eridanus, which depicts a river. The river starts near the lower right corner of Orion, near the bright star Rigel and flows to the right then down near the southern horizon, then it meanders below the horizon. One has to travel to the far southern United States or even farther south to see the southern terminus of the river, the bright star Achernar. Writers over the ages have seen here the Nile and the earth circling river Ocean of the flat earth days. One of its stars is close to us and famous. It’s Omicron 2 Eridani a triple star system and the fictional home to Mr. Spock and other Vulcans of the Star Trek franchise. No real planet has been found there. Yet.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Note: In previous posts about Eridanus I had identified Epsilon Eridani and the fictional Mr. Spock’s home star. It’s actually Omicron 2 according to Gene Roddenberry himself.
Speaking of Vulcan, Star Trek fans nominated Vulcan for one of the names for Pluto’s latest two satellites, apparently forgetting that Vulcan was borrowed from Roman mythology as the god of fire, and the history of astronomy. Pluto and its satellites are some of the coldest bodies in the solar system, and the International Astronomical Union (IAU) had designated that the satellites carry on the Pluto and Hades or underworld theme. Anyway, in the mid 19th century some astronomers thought they discovered a planet that resided inside the orbit of Mercury and named it appropriately, Vulcan. If anything is ever found orbiting inside Mercury, it may get the name Vulcan. As for the names of the latest two moons of Pluto, they are Styx named after the the River Styx; and Kerberos, Greek for Cerberus the three headed dog that guards the entrance to Hades. Harry Potter fans may know this creature better as “Fluffy”.
The constellation of the river Eridanus above and below the horizon for 9 p.m. on January 23, 2014. Created using Cartes du Ciel (Sky Charts).
01/21/2014 – Ephemeris – Orion’s hunting dogs
Ephemeris for Tuesday, January 21st. The sun will rise at 8:11. It’ll be up for 9 hours and 24 minutes, setting at 5:36. The moon, 3 days before last quarter, will rise at 11:23 this evening.
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 facing Orion that appears to be begging. The smaller dog can be found by extending a line through Orion’s shoulder stars to the left. We find a bright star called Procyon. It and one other star make up the hot-dog shaped constellation of Canis Minor, the little dog.
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. on January 21, 2014. Created using Stellarium.
12/27/2013 – Ephemeris – The star Procyon: “Before the Dog”
Ephemeris for Friday, December 27th. The sun will rise at 8:18. It’ll be up for 8 hours and 50 minutes, setting at 5:08. The moon, 2 days past last quarter, will rise at 3:48 tomorrow morning.
Yesterday I talked about the brilliant star Sirius, the dog star pointed to by the stars of the belt of Orion. Today we’ll look at another dog star. Procyon, the bright star in Canis Minor, the lesser dog. It is pointed to by the top two stars in the Orion rectangle Bellatrix and Betelgeuse. One of the translations of Procyon means “Before the Dog”. This seemingly odd title is explained that even though Procyon is east of Sirius and all things being equal, well at least latitude or declination the eastern star should rise after the western star. However Procyon is north of Sirius and if one is sufficiently north of the equator, the eastern most star can rise first. This is what happens. Procyon is a bit farther away than Sirius and isn’t quite as bright either.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Procyon is already up as Sirius rises. Procyon also sets after Sirius. Created using Stellarium.
Note: Stellarium approximates atmospheric extinction, that is dims objects when they are near the horizon an effect due to looking through more of the Earth’s atmosphere when looking close to the horizon. That’s why Sirius looks rather fainter than in yesterday’s image.
12/26/2013 – Ephemeris – Sirius, the brightest night-time star
Ephemeris for Thursday, December 26th. The sun will rise at 8:18. It’ll be up for 8 hours and 49 minutes, setting at 5:08. The moon, 1 day past last quarter, will rise at 2:40 tomorrow morning.
At 9 in the evening the great constellation of Orion the hunter can be seen in the southeast. Its large rectangle of bright stars is tilting to the left, while in the center is a row of three stars, his belt. These stars tilt downward and a bit to the left to a very bright star merrily twinkling above the horizon in the southeast. This star is called Sirius, also known as the Dog Star because it’s in the heart of Orion larger hunting dog, Canis Major. It is an arc light white star as seen in binoculars or telescope. It’s a neighboring star, just twice the distance of the closest star to the sun at 8.6 light years. It’s name, Sirius, has nothing to do with a dog, but is from the Greek meaning scorching for its brightness or sparkling, due to its intense twinkling.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
How to find Sirius from Orion. 9 p.m., December 26, 2013. Created using Stellarium.
12/23/2013 – Ephemeris – The constellation Orion: The hard luck hero
Ephemeris for Monday, December 23rd. The sun will rise at 8:17. It’ll be up for 8 hours and 49 minutes, setting at 5:06. The moon, 2 days before last quarter, will rise at 11:29 this evening.
The large and bright constellation of Orion is now in the southeast at 9 p.m. It is seen as an upright rectangle of bright stars tilting to the left, his shoulders and knees, with a belt of three stars in the center. Orion is a minor character in Greek mythology, much less celebrated than Hercules, which has a dim constellation named for him. Orion was a hunter. He had an ill-fated romance with Merope, whose father King Oenopion, had him blinded. After having his sight restored, Orion became a companion of Diana goddess of the hunt and they wanted to marry. Apollo, Diana’s brother disapproved of Orion also and was able to trick Diana into accidentally killing Orion with her bow. Another story had Orion dying of a scorpion sting.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Taurus and Orion with Orion’s brightest stars named. Created using Stellarium.
12/16/2013 – Ephemeris – Orion’s bright blue-white star Rigel
Ephemeris for Monday, December 16th. The sun will rise at 8:13. It’ll be up for 8 hours and 49 minutes, setting at 5:03. The moon, 1 day before full, will set at 8:07 tomorrow morning.
Last week I talked about the star Betelgeuse the bright red star in the top left of Orion’s rectangle in the hunter’s shoulder. Orion is seen in the southeast 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 17 solar masses. Its surface temperature is more than twice as hot as the sun. It is 130 thousand times as bright as the sun and 74 times its diameter. Its distance is around 860 light years. A telescope might reveal a close companion star to Rigel, off 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
Taurus and Orion with Orion’s brightest stars named. Created using Stellarium.
12/12/2013 – Ephemeris – The bright star Betelgeuse (Don’t say it three times)
Ephemeris for Thursday, December 12th. The sun will rise at 8:10. It’ll be up for 8 hours and 52 minutes, setting at 5:02. The moon, 3 days past first quarter, will set at 4:26 tomorrow morning.
The bright red star in the constellation Orion’s shoulder is Betelgeuse, and it’s about 643 light years away. Despite its great distance, it is the star whose surface is easiest seen, after the sun of course. That’s because it’s so big, maybe as large around as the orbit of Jupiter. Its true diameter is hidden by the cloud of gas it’s expelling. Betelgeuse varies in size and brightness, so its size varies by nearly 30 percent. The Hubble telescope has sent back pictures of the star, and has found a bright spot, seen in ultraviolet light on what may be its surface. It has a really hot core generating energy that pushes out its gaseous envelope to a great size. Some astronomers think the Betelgeuse will become a supernova within a million years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aldebaran, the Hyades, of Taurus, Orion and the Pleiades at 10 p.m. December 12, 2013. Created using Stellarium.
“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)
12/10/2013 – Ephemeris – The bright star Aldebaran, the Follower
Ephemeris for Tuesday, 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 past first quarter, will set at 2:18 tomorrow morning.
The central constellation of winter, Orion, is in the east southeast at 9 p.m. Above it is Taurus the bull. The bright orange star in Taurus is Aldebaran. Aldebaran appears at the lower left tip of a letter V group of stars lying on its side that is the face of the bull. Aldebaran isn’t actually part of the group, called the Hyades star cluster. The cluster is about 153 light years away, while Aldebaran is 65. The star has an orange hue because its surface is cooler than the sun’s. However Aldebaran is 44 times larger in diameter, and shines 465 times brighter than the sun. The name Aldebaran means “Follower” because it follows the Pleiades star cluster through the skies. The Pleiades is above right of Aldebaran.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aldebaran, the Hyades, of Taurus, Orion and the Pleiades at 10 p.m. December 10, 2013. Created using Stellarium.
12/05/2013 – Ephemeris – The constellation Taurus the bull
Ephemeris for Thursday, December 5th. The sun will rise at 8:03. It’ll be up for 8 hours and 58 minutes, setting at 5:02. The moon, 3 days past new, will set at 8:27 this evening.
Early in the evening the moon will appear above the bright planet Venus in the southwest. 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 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.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Taurus and Orion in the east at 9 p.m, December 5, 2013. Created using Stellarium.
12/03/2013 – Ephemeris – Orion rises
Ephemeris for Tuesday, December 3rd. The sun will rise at 8:01. It’ll be up for 9 hours and 1 minute, setting at 5:03. The moon, 1 day past new, will set at 6:07 this evening.
At 9 p.m. the constellation of Orion the giant hunter will be rising in the east southeast, with its belt stars nearly vertically aligned. The belt stars are contained within a tilted rectangle of four bright stars that’s leaning to the left. The brightest of the top stars is Betelgeuse a bright red star about the hue of the planet Mars. It’s a huge red giant star. Both top stars are Orion’s shoulders. The other shoulder star is Bellatrix. The bottom stars are Orion’s knees. The brightest, diagonally opposite from Betelgeuse is Rigel, a bright blue-white giant star. The other knee star is named Saiph. Orion is home to a beautiful nebula or cloud of gas, which we’ll explore later this winter. Jupiter is the bright stellar looking object to the left of Orion.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion Rising and other winter constellations at 9 p.m. December 3, 2013. Created using Stellarium
Bob Moler's Ephemeris Blog 