Archive
09/26/11 – Ephemeris – The sun is getting very active again
Monday, September 26th. The sun will rise at 7:34. It’ll be up for 11 hours and 58 minutes, setting at 7:32. The moon, 1 day before new, will rise at 7:53 tomorrow morning.
There is a large sunspot group rotating onto the earth facing side of the sun. It has already produced two large solar flares. Flares are explosions caused by the snapping of the magnetic field lines that cause the sunspots in the first place. The most energetic of these throw off a huge cloud of charged particles, protons, electrons, and alpha particles called a coronal mass ejection or CME at a couple of million miles an hour. It takes 36 to 48 hours for the cloud to reach the earth. Then it tangles with the earth’s magnetic field causing a geomagnetic storm. This is not good news for satellite operators and power and phone companies in the north. However for the rest of us, we get a chance to see the northern lights or Aurora Borealis. Saturday’s two flares from that sunspot group sent out a CME that we may catch the tail of later today.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/23/11 – Ephemeris – Autumn is already here
Friday, September 23rd. The sun will rise at 7:30. It’ll be up for 12 hours and 8 minutes, setting at 7:38. The moon, 3 days past last quarter, will rise at 4:00 tomorrow morning.
Autumn has arrived. It snuck in at 5:05 a.m. At that instant the sun passed over the celestial equator, earth’s equator projected on the sky, heading southward. By Monday the sun will be up less than 12 hours a day, heading to less than 9 hours at the start of winter, three month’s away. It is the tilt of the earth’s axis, which is fixed as the earth orbits the sun that causes the sun to appear to change its height in the sky at noon and the length of daylight that warms the earth. Its is not the small change in the distance of the earth from the sun. And besides the earth is currently moving closer to the sun and will arrive at its closest, called perihelion in early January.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/22/11 – Ephemeris – The Constellations Delphinus and Sagitta
Thursday, September 22nd. The sun will rise at 7:29. It’ll be up for 12 hours and 11 minutes, setting at 7:40. The moon, 2 days past last quarter, will rise at 2:47 tomorrow morning.
Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is overhead in our sky at 10 p.m., is the tiny constellation of Delphinus the dolphin. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do, and told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow a small thin group of 5 stars, which represents Cupid’s dart. Behind Sagitta binoculars will find a little star group called the Coat hanger.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Delphinus, Sagitta and the Coat hanger. Diagram created using Stellarium.
09/21/11 – Ephemeris – The bright planets this week
Wednesday, September 21st. The sun will rise at 7:28. It’ll be up for 12 hours and 14 minutes, setting at 7:42. The moon, 1 day past last quarter, will rise at 1:37 tomorrow morning.
It’s Wednesday and time again to take a look at the whereabouts of the bright planets. The planet Venus is rather close to the sun in the evening setting 26 minutes after the sun and not really visible. The ringed planet Saturn also hidden in the bright twilight is setting 51 minutes after the sun. Jupiter is now the prominent planet of the evening sky after it rises at 9:13 p.m. in the east northeast and is seen against the stars of the constellation Aries now. In a telescope it will be accompanied by its 4 brightest moons, and as the planet rises higher Jupiter’s image becomes sharper, and its cloud bands will become visible. Mars will rise at 2:25 a.m also in the east northeast and is now between the constellations of Gemini and Cancer.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/20/11 – Ephemeris – The constellation Andromeda
Tuesday, September 20th. The sun will rise at 7:26. It’ll be up for 12 hours and 17 minutes, setting at 7:44. The moon, at last quarter today, will rise at 12:33 tomorrow morning.
In the east southeast at 9 this evening can be found a large square of stars, the Great Square of Pegasus the flying horse. The square is standing on one corner. What look like its hind legs stretching to the left from the left corner star is another constellation, Andromeda the chained maiden. She is seen in the sky as two diverging curved strings of stars that curve upward. She was rescued by the hero Perseus, a nearby constellation, riding his steed Pegasus. Andromeda’s claim to astronomical fame is the large galaxy seen with the unaided eye just above the upper line of stars. The Great Andromeda Galaxy is two and a half million light years away. To the unaided eye the galaxy appears a a small smudge of light. In binoculars the galaxy is a delicate spindle of light.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Constellation Andromeda. Created using Stellarium.
The Great Andromeda Galaxy (M31). Image taken by Scott Anttila.
Click on image for full size version.
Stellarium has it by its old name the Great Andromeda Nebula, before it was reclassified as an island universe (obsolete) or galaxy.
09/19/11 – Ephemeris – Talk Like a Pirate Day and the constellation Pegasus
Arrrh! This is Cap’n Bob with Ephemeris for Talk like a Pirate Day, Monday, September 19th. I can’t keep this up. The sun will rise at 7:25. It’ll be up for 12 hours and 20 minutes, setting at 7:46. The moon, 1 day before last quarter, will rise at 11:35 this evening.
A reminder of the end of summer is located in the east around 9 p.m. It’s one of the great autumn constellations: Pegasus the flying horse of Greek myth. Its most visible feature is a large square of four stars, now standing on one corner. This feature, called the Great Square of Pegasus, represents the front part of the horse’s body. The horse is quite aerobatic, because it is seen flying upside down. Remembering that fact, the neck and head is a bent line of stars emanating from the right corner star of the square. Its front legs can be seen in a gallop extending to the upper right from the top star of the square. In Mythology Pegasus was born of the blood of Medusa, decapitated by the hero Perseus.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Pegasus at 9 p.m. Chart created using Stellarium.
09/16/11 – Ephemeris – Astronomical observing events this weekend in northern Michigan
Friday, September 16th. The sun will rise at 7:22. It’ll be up for 12 hours and 29 minutes, setting at 7:51. The moon, half way from full to last quarter, will rise at 9:27 this evening.
This evening the Grand Traverse Astronomical Society will host a viewing night at Northwestern Michigan College’s Rogers Observatory starting at 9 p.m. The featured objects of the evening will be the planet Jupiter and the moon. Jupiter is the largest planet and has 65 satellites, of which the four discovered by Galileo are large enough to be easily seen. Three of these are larger than our moon. The observatory is located south of Traverse City, on Birmley Road between Garfield and Keystone roads. Also this weekend, tomorrow members of the society will bring their telescopes to the Leland Heritage Celebration to safely view the sun, which has recently become vary active. Times for this event are 10 a.m to 3 p.m.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/15/11 – Ephemeris – The waning gibbous moon tonight
Thursday, September 15th. The sun will rise at 7:21. It’ll be up for 12 hours and 32 minutes, setting at 7:53. The moon, 3 days past full, will rise at 8:56 this evening.
I don’t usually talk about the moon after it becomes full, but because of the harvest moon effect its still rises early. The moon’s phase is now a waning gibbous, with the sunset line now crossing the moon from right to left. Visible are the dark seas including to the upper right the scallop shell shaped Sea of Serenity. In telescopes at its right edge will be the crater Posidonus a flat crater, 58 miles in diameter, with low walls with an inner partial crater ring within. Larger telescopes may be able to see cracks or rilles in its floor. The sea south of Serenity is Tranquility where Apollo 11 landed and by tomorrow night the sun will nearly have set there as well as having encroached on Serenity
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The moon 9/15/11 10 p.m. Created using Virtual Moon Atlas.
09/14/11 – Ephemeris – The bright planets visible this week
Wednesday, September 14th. The sun will rise at 7:19. It’ll be up for 12 hours and 35 minutes, setting at 7:55. The moon, 2 days past full, will rise at 8:29 this evening.
It’s Wednesday and time again to take a look at the whereabouts of the bright planets. The planet Venus is rather close to the sun in the evening setting 23 minutes after the sun and not really visible. The ringed planet Saturn is not really visible in the west in evening twilight. It will set 45 minutes after the sun. Jupiter is now the prominent planet of the evening sky after it rises at 9:41 p.m. in the east northeast and is seen against the stars of the constellation Aries now. It will be accompanied by its 4 brightest moons. Mars will rise at 2:31 a.m also in the east northeast and is now between the constellation Gemini and Cancer. Mercury is briefly visible now from about half an hour after its rising in the east at 6:17 until about 7 a.m.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
09/13/11 – Ephemeris – Supernova in the Pinwheel Galaxy
Tuesday, September 13th. The sun will rise at 7:18. It’ll be up for 12 hours and 38 minutes, setting at 7:57. The moon, 1 day past full, will rise at 8:05 this evening.
There is currently a supernova in a galaxy near the handle of the Big Dipper. The bright moon is interfering with its visibility in telescopes. It’s in a galaxy called M101 or the Pinwheel galaxy, a difficult to spot galaxy between and above the two end stars of the handle of the Big Dipper. The galaxy is 21 million light years away, relatively close as galaxies go. It is being intensely studied because it is of a type, 1a, that is used for distance measurements of far more distance galaxies. This kind of Supernova is thought to be the destruction of a white dwarf star in a close binary relation with a more massive star and is drawing matter off the larger star. When the dwarf reaches 1.38 times the sun’s mass… Kablooey! Astronomers are trying to see if that’s true for this star.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
