Archive
05/11/2015 – Ephemeris – How to find the constellation Virgo
Ephemeris for Monday, May 11th. Today the Sun will be up for 14 hours and 39 minutes, setting at 8:59. The Moon, at last quarter today, will rise at 3:08 tomorrow morning. Tomorrow the Sun will rise at 6:18.
Friday I talked about that in spring we are looking out the thin side of our Milky Way galaxy’s disk. One of the large constellations we see in the south at 11 p.m. can be found using the Big Dipper overhead, follow the arc of the handle to the bright star Arcturus, the straighten the arc to a spike to reach Spica, a bright blue-white star in the south. Spica is the brightest star in the constellation Virgo the virgin. She represents the goddess of the harvest, Virgo is holding a sheaf of wheat in depictions of her, and Spica is placed at the head of the sheaf. In the space between Spica and Leo the lion to her right is, a great cluster just below naked eye visibility. The Virgo cluster of galaxies.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Star hop from the Big Dipper through Arcturus to Spica and Virgo. Orientation for 11 p.m. on May 11, 2015. Created using Stellarium.
4/16/2015 – Ephemeris – A constellation commemorating a real person
Ephemeris for Thursday, April 16th. The Sun rises at 6:57. It’ll be up for 13 hours and 31 minutes, setting at 8:28. The Moon, 2 days before new, will rise at 6:19 tomorrow morning.
Half way up the sky in the east-southeast at 10 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. 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 was away at war. This was in the days when the Greeks ruled Egypt after Alexander 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.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Coma Berenices and neighboring constellations at 10 p.m. on April 16, 2015. Note that only the upper right star of the upside down L shape actually belongs to the cluster. Created using Stellarium.
04/14/2015 – Ephemeris – Arcas and Callisto
Ephemeris for Tuesday, April 14th. The Sun will rise at 7:00. It’ll be up for 13 hours and 25 minutes, setting at 8:26. The Moon, 3 days past last quarter, will rise at 5:08 tomorrow morning.
Rising in the eastern sky at 10 p.m. tonight is the kite shaped constellation of Boötes the herdsman. The bright star Arcturus is at the bottom of the kite, pointed to by the arc of the handle of the Big Dipper, overhead. In one story Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young lady who had the misfortune of being loved by Zeus the chief Greek god. Zeus’ wife Hera, found out about it, and since she couldn’t punish Zeus, turned Callisto into an ugly bear. Arcas, unaware of why his mother disappeared in his youth was about to kill the bear when Zeus intervened and placed them both in the sky. Now Arcas as Boötes chases the Great Bear forever around the pole of the sky each night.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Bootes and Ursa Major aka Arcas chasing Callisto around the pole of the sky. Created using Stellarium.
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04/13/2015 – Ephemeris – The Big Dipper as seen from many lands
Ephemeris for Monday, April 13th. The Sun will rise at 7:02. It’ll be up for 13 hours and 22 minutes, setting at 8:25. The Moon, 2 days past last quarter, will rise at 4:31 tomorrow morning.
The Big Dipper will be high in the east, nearly overhead at 10 p.m. It is officially part of Ursa Major, the Great Bear. Other cultures have different representations for this star group. It’s the plough (plow), Charles’ Wain (Charlemagne’s Wagon), the Saucepan, or the Cleaver depending on the country. It performs an invaluable service in pointing out other stars and constellations, especially the star Polaris the north star. That star, which seems to hover over the north pole of the Earth can be found by using the two stars at the front of the bowl of the dipper to point to it. And at our latitude of around 45 degrees north, the Big Dipper is always in the sky. It is one of the circumpolar star groups that can be seen in any season.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Right now in the spring the Big Dipper is nearly overhead pointing down to Polaris. I’ve turned these upside down so the images make more sense.
The Big Dipper or Sauce Pan. Credit: Bob Moler’s LookingUp program.
For runaway slaves fleeing northward at night it was their compass… “Follow the Drinking Gourd”
The Plough or plow in American. Credit: Bob Moler’s LookingUp program.
Charles’ Wain. Credit: Bob Moler’s LookingUp program.
The Cleaver. Credit: Bob Moler’s LookingUp program.
Do you know any others?
04/09/2015 – Ephemeris – Two water creatures among the stars
Ephemeris for Thursday, April 9th. The Sun will rise at 7:09. It’ll be up for 13 hours and 10 minutes, setting at 8:20. The Moon, 2 days before last quarter, will rise at 1:30 tomorrow morning.
Hydra the water snake is the longest of the constellations. Its head is a group of five stars in a close group below a line between Leo the Lion and Gemini the twins in the southwest. This year it is below Jupiter. Its stars drop down and skirt the horizon underneath Corvus the crow, an interesting box-like constellation and Virgo and dip below the horizon in the southeast. It takes a low southern horizon to follow its body that far. It’s brightest star is Alphard. To the native peoples around here the sickle of Leo, the head of Hydra and stars down to Alphard made the Great Underwater Leopard, ready to snatch the foolish who ventured out on the thin ice and broke through this time of year.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Hydra finder chart for 9:30 p.m. April 9, 2015. Created using Stellarium.
The Anishinaabek Great Underwater Panther. 9:30 p.m. April 9, 2015. Created using Stellarium. Constellation by Bob Moler, based on a video by Michael Wassegijig Price.
The video is here.
04/06/2015 – Ephemeris – Arcturus the 4th brightest star
Ephemeris for Monday, April 6th. The Sun will rise at 7:14. It’ll be up for 13 hours and 1 minute, setting at 8:16. The Moon, 2 days past full, will rise at 10:37 this evening.
One of the stars that stays up most of the year, except late autumn and most of winter is Arcturus. Now in the evening Arcturus is low in the east. It’s a bright star, officially the 4th brightest star in the night sky, and the 4th brightest star-like object in our night sky after Venus, Jupiter, and Sirius. Arcturus can be found by following the arc of the handle of the Big Dipper to it. Remember, follow the arc to Arcturus. Arcturus belongs to the kite shaped constellation of Boötes, which we’ll visit in greater detail when it’s higher in the sky. Arcturus is an interesting star. It’s 37 light years away, and moving quite rapidly at 75 miles per second (122km/s), mostly across the sky. Some astronomers think that it
Arcturus off the handle of the Big Dipper at 9:30 p.m. April 6, 2015. Created using Stellarium.
may be part of a captured dwarf galaxy.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
03/26/2015 – Ephemeris – Regulus the 21st brightest of the 21 brightest “First Magnitude” stars
Ephemeris for Thursday, March 26th. The Sun will rise at 7:35. It’ll be up for 12 hours and 27 minutes, setting at 8:02. The Moon, 1 day before first quarter, will set at 3:04 tomorrow morning.
The bright star below and left of Jupiter as it shines in the southeast in the evening is the star Regulus in Leo the lion. It’s at the base of the backward question mark of stars that make up the head and mane of Leo. It is also an asterism or informal constellation of the Sickle. Regulus is the dimmest of the 21 brightest stars which are called First Magnitude Stars. It is a quadruple star system with two pairs of stars. Regulus is a blue-white star which is rapidly spinning with a period of something like 16 hours, orbited by a possible white dwarf star every 40 days. The star system is 79 light years away. The name Regulus translates to something like Little King Star, befitting its location in the King of the beasts.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Leo, Regulus and nearby constellations as seen in the east-southeast at 9 p.m. March 26, 2015. Created using Cartes du Ceil (Sky Charts).
Below, zooming in to Regulus BC, the second pair of stars of the Regulus system, which is about 3 minutes of arc northwest of Regulus. It consists of an 8th magnitude and a 14th magnitude star with the same proper motion (motion against the sky) as Regulus.
The star TYC 833-134-1 is Regulus B, which is easily visible in telescopes at magnitude 8.1. The star is also listed as HD 87844. The first designation is from the Tycho catalog and is how it’s referenced in Cartes du Ceil. The star is shown, but not named in Stellarium. The is equatorial orientation is created using Cartes du Ceil (Sky Charts).
03/13/2015 – Ephemeris – Leo rising
Ephemeris for Friday, March 13th. The Sun will rise at 7:59. It’ll be up for 11 hours and 46 minutes, setting at 7:46. The Moon, at last quarter today, will rise at 3:35 tomorrow morning.
The constellation Leo the lion is now rising in the east at 9 pm. It’s below and left of the Big Dipper higher up in the east-northeast. Leo is marked by two sets of easily recognizable stars. The front of him is a backward question mark of stars, also known as the Sickle that mark his head and mane, along with the front part of his body. Regulus is the star at the bottom of that backwards question mark. It’s the Little King Star. Jupiter this year is above right if it. The hind end of him is a triangle of stars ending with another bright star, but not as bright as Regulus. It’s Denebola which means Lion’s tail. It is thought when the sun was in this constellation long ago that the lions were driven by the heat to quench their thirst in the Nile river. Ancients physicians thought medicines were poison when the sun was here too.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Leo rising in the east behind Jupiter at 9 p.m. on March 13, 2015. Created using Stellarium.
03/10/2015 – Ephemeris – The Great Orion Nebula
Ephemeris for Tuesday, March 10th. The Sun will rise at 8:04. It’ll be up for 11 hours and 37 minutes, setting at 7:42. The Moon, 3 days before last quarter, will rise at 12:43 tomorrow morning.
The constellation of Orion the hunter, now in the south at 9 p.m., contains the most beautiful star forming region in the northern sky. It is the Great Orion Nebula. A nebula is simply a cloud. Back in the early days of telescopes it was anything that appeared fuzzy. Today it’s any cloud, whether of gas or dust, light or dark. The Great Orion Nebula is made up of gas, which is ionized and shines by fluorescence by the ultraviolet light of a clutch of four stars in its heart called the Trapezium. The nebula can be glimpsed with binoculars surrounding what looks like the center star of the vertical line of three stars that appears as the sword hanging from Orion’s belt. It’s the bright end of a large dark cloud that’s behind the bright stars of Orion.
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.
The lower part of Orion with the Great Orion Nebula. Created using Stellarium.
Inner part of the Great Orion Nebula with the Trapezium. Image by Scott Anttila
Great Orion Nebula by Scott Anttila
03/09/2015 – Ephemeris – The Big Dipper, a sign of spring
Ephemeris for Monday, March 9th. The Sun will rise at 8:06. It’ll be up for 11 hours and 34 minutes, setting at 7:40. The Moon, 4 days before last quarter, will rise at 11:43 this evening.
There’s a sign of spring appearing in the sky, rising high in the northeast. It’s the Big Dipper standing on its handle. In the native story of the Fisher Star, it’s the sign that it’s time for the maple sugar season. The Big Dipper is part of Ursa Major the great bear or a weasel-like creature called Fisher or Fisher Star. Draw a line through the bottom of the bowl of the dipper as if it leaks, and it will drip on the back of Leo the lion in the southeast. The handle of the Big Dipper will arc to Arcturus after 10 p.m. when that star rises. The most important guide that the Big Dipper provides is to point to Polaris, the north star. The two stars at the front of the bowl of the dipper point to Polaris, that alone of all the stars appears fixed in the north.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Big Dipper, part of Ursa Major and also part of Fisher Star in the northeastern sky at 9 p.m. March 9, 2015
For the story of Fisher Star follow this link.
Bob Moler's Ephemeris Blog 