Archive
12/23/11 – Ephemeris – This year’s Christmas stars
Friday, December 23rd. The sun will rise at 8:17. It’ll be up for 8 hours and 48 minutes, setting at 5:06. The moon, 1 day before new, will rise at 8:04 tomorrow morning.
We have two bright planets and the brightest nighttime star out to be our Christmas stars this year. The planet Venus appears in the southwest in the evening and in seen higher and higher each evening, leading the sun in its slow climb as we move through winter into spring. Jupiter holds forth high in the south, the brightest star-like object once Venus sets. The brightest of all the night-time stars is Sirius, whose name means “Dazzling One” rising higher in the southeast, whiter than any planet with a tinge of blue, especially when seen in binoculars or a telescope.. It is accompanied by the rest of the bright stars of winter, including those of the great constellation Orion the hunter, whose three stars of his belt point down and to the left at Sirius.
* Times, as always are for the Traverse City/Interlochen area of Michigan.
12/20/11 – Ephemeris – Procyon, the “Little Dog Star”
Tuesday, December 20th. The sun will rise at 8:15. It’ll be up for 8 hours and 48 minutes, setting at 5:04. The moon, 3 days past last quarter, will rise at 4:45 tomorrow morning.
Visible low in the east at 9 p.m. appears the star Procyon to its lower left is Sirius the brightest night time star. Procyon is the bright star in the constellation Canis Minor, or lesser dog. I can find only one other star in Canis Minor. Perhaps it’s a hot dog. If Sirius, in Canis major is the Dog Star then Procyon should be the Little Dog Star. However Procyon is an interesting name. It means “Before the dog”, which is an allusion to the fact that Procyon, though east of Sirius actually rises before it. This is due to Procyon’s more northerly position. This effect doesn’t work south of the equator, however. Procyon is a star much like Sirius but farther away. [It’s 11.41 to Sirius’ 8.6 light years away. And like Sirius it even has a small white dwarf star in its system.]
* Times, as always are for the Traverse City/Interlochen area of Michigan. Text in brackets was omitted in the audio program due to time constraints.
Addendum
Procyon, Sirius and the stars of winter. Created using Stellarium
The grid lines are right ascension and declination, analogous to longitude and latitude on the earth. Looking eastward the right ascension lined run from the upper left to the lower right. Thus Procyon is definitely farther east than Sirius.
10/31/11 – Ephemeris – The spookiest star
Halloween, Monday, October 31st. The sun will rise at 8:18. It’ll be up for 10 hours and 14 minutes, setting at 6:33. The moon, 2 days before first quarter, will set at 11:04 this evening.
On the spookiest night of the year, lets look at the spookiest star of all. It’s Algol, from Ghoul Star or Demon Star. The Chinese had a name for it that meant ‘piled up corpses’. It’s the second brightest star in the constellation Perseus the hero, rising in the northeast this evening. The star is located where artists have drawn the severed head of Medusa, whom he had slain. Medusa was so ugly that she turned all who gazed upon her to stone. Algol is her still glittering eye. Astronomers finally found out what was wrong with Algol. It does a slow 6 hour wink every two days 21 hours, because it is two stars that eclipse each other. It will be winking this evening, dimmer than usual. My ephemeris blog has a finder chart. Just Google Bob Moler.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
10/27/11 – The Harbinger of Winter – Capella
Thursday, October 27th. The sun will rise at 8:13. It’ll be up for 10 hours and 25 minutes, setting at 6:39. The moon, 1 day past new, will set at 7:02 this evening.
A bright star called Capella has slowly been rising in the northeastern sky in the evenings for the past few months. At 9 p.m. now it is low in the north northeast far below the letter “W” shaped constellation of Cassiopeia. This winter Capella will be overhead the highest of winter’s seven brilliant first magnitude stars. Capella never quite sets for anyone north of Ludington. Due to its brightness, and being the closest first magnitude star to the pole Capella appears to move slowly as the earth rotates, and spends summer and autumn evenings close to the horizon. In the sky Capella represents a mamma goat held on the shoulders of a charioteer. There’s a thin triangle of three stars to Capella’s lower right. It’s a group of stars called the Kids. Her kids.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Capella and the Kids in the early evening. Created using Stellarium.
10/25/11 – Ephemeris – The lonely star Fomalhaut
Tuesday, October 25th. The sun will rise at 8:10. It’ll be up for 10 hours and 31 minutes, setting at 6:42. The moon, 1 day before new, will rise at 8:02 tomorrow morning
There’s a bright and lonely star that appears low in the south for only seven and a half hours a night on autumn evenings. It’s appearance is a sign as sure as the falling leaves that autumn is here At 9 p.m. tonight it’s low in the south southeast. The star’s name is Fomalhaut, which means fish’s mouth. This is appropriate because it’s in the constellation of Piscis Austrinus, the southern fish. At our latitude it’s the fish that got away, because Fomalhaut appears to be quite alone. The dimness of the constellation’s other stars and location close to the horizon make the fainter stars hard to spot. They would be overhead in Australia. The earth’s thick atmosphere near the horizon reduces the stars brightness by a factor of two or more, so Fomalhaut appears to keep a lonely vigil in the south.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aquarius and Fomalhaut as visualized by Stellarium
09/29/11 – Ephemeris – Deneb at the zenith
Thursday, September 29th. The sun will rise at 7:37. It’ll be up for 11 hours and 49 minutes, setting at 7:27. The moon, 2 days past new, will set at 8:28 this evening.
At 10 p.m. tonight the first magnitude star Deneb will be overhead, that is very near the zenith. Deneb is the northern most and dimmest of the three stars of the Summer Triangle. It is at the head of the Northern Cross, which extends to the south. This is an asterism, which is what astronomers call a informal constellation. The Big and Little Dippers are also examples of asterisms. You won’t find them in the list of the 88 official constellations. The actual constellation that Deneb belongs to is Cygnus the swan. In the swan Deneb is the tail. That’s actually what Deneb means. The swan is flying southwestward along the Milky Way with its wings outstretched. Stars can be followed around the wings to make out a very realistic flying swan.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Deneb at the Zenith. Looking overhead while facing south. Created using Stellarium.
The Summer Triangle of bright stars Deneb, Vega and Altair are in this view.
08/30/11 – Ephemeris – The bright star Altair
Tuesday, August 30th. The sun will rise at 7:02. It’ll be up for 13 hours and 20 minutes, setting at 8:23. The moon, 2 days past new, will set at 8:48 this evening.
The Summer Triangle of bright stars is visible overhead and to the south.. Vega is highest, nearly overhead, while Deneb is high in the northeast. The southernmost star of the Summer Triangle is Altair. Altair is the closest of the three stars at a distance of 16.8 light years away. One light year is nearly 6 trillion miles. Altair is 10 times the brightness of the sun. If seen at Altair’s distance, the sun would only be as bright as one of the two stars that flank it. What is rather different about Altair is it’s rapid rotation. While its almost twice the sun’s diameter, it rotates once in only 6 ½ to 10 hours, and would show a decidedly squashed appearance if seen close up. Our sun’s a slow poke, taking nearly a month to rotate just once.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
08/29/11 – Ephemeris – The twinkly red star Antares
Monday, August 29th. The sun will rise at 7:01. It’ll be up for 13 hours and 23 minutes, setting at 8:24. The moon, 1 day past new, will set at 8:19 this evening.
As it gets dark this evening a bright reddish star will appear low in the south. It will appear to twinkle mightily. It is not the planet Mars, which is now in the morning sky, but its rival the star Antares in Scorpius the scorpion. The star’s name, Antares, notes the rivalry. “Ant” means anti, while “Ares” is the Greek name for the Roman god Mars. Antares literally means “Rival of Mars”. Antares appears red due to its cool surface temperature of 3,600 Kelvin, much cooler than the sun’s 6,000 Kelvin, while Mars is red due to rust. As Antares starts to set later in the evening its light will mass through more of earth’s turbulent atmosphere making it sparkle like a multicolored sparkler. Antares spectacular twinkling has sparked more than a few calls about a strange light in the sky.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location
07/19/11 – Ephemeris – The brightest stars visible now in the evening
Tuesday, July 19th. Today the sun will be up for 15 hours and 6 minutes, setting at 9:21. The moon, half way from full to last quarter, will rise at 11:11 this evening. Tomorrow the sun will rise at 6:15.
Let’s check out all the bright stars in the evening sky, as it gets dark tonight. High in the west is the bright yellow-orange star Arcturus. In the northwest is the Big Dipper, whose curved handle points to Arcturus. Straightening that curve to a spike will point to Spica a blue-white star low in the southwest. The bright star to its right isn’t. It’s the planet Saturn. In the south is the red star Antares which usually twinkles merrily. High in the east is the bright white star Vega. To its lower right is Altair, and to its lower left the star Deneb. Vega, Altair and Deneb make the Summer Triangle, whose rising in the east signals the coming of summer. Always present for us in northern Michigan is Capella very low in the north.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Bright Summer Stars. Created using Stellarium.
Click on the image to enlarge. This is a whole sky chart. The round edge is the horizon. BTW the star Capella, very low in the north, is a winter star, but it’s visible all year round for folks north of 44 degrees north latitude.
07/04/11 – Ephemeris – Red, white and blue stars
Independence Day, Monday, July 4th. Today the sun will be up for 15 hours and 27 minutes, setting at 9:30. The moon, 3 days past new, will set at 11:22 this evening. Tomorrow the sun will rise at 6:03.
Today’s Independence Day so let’s look for some red, white, and blue stars. Red is easy, the red star Antares is seen in the south at 11 p.m. White is easy too, the official white calibration star Vega high in the east at 11 p.m. The blue star is really blue-white. The brightest of these out at 11 p.m. is Spica, low in the southwest. The color is best seen in binoculars. Star colors are quite subtle, and are an indicator of the temperature of their outer gaseous layers. The temperature of a stars outer layers, in order of their increasing temperatures, red, white and blue, is not related to the temperature in their cores. Of these three the coolest on the outside, Antares is really the hottest inside, using helium as fuel.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Bob Moler's Ephemeris Blog 