Archive
11/07/11 – Ephemeris – A closer look at Jupiter
Monday, November 7th. The sun will rise at 7:27. It’ll be up for 9 hours and 55 minutes, setting at 5:23. The moon, 3 days before full, will set at 5:24 tomorrow morning.
Jupiter is the planet to spot in the evening sky. It’s in the east in the early evening. I’ve talked to some folks who thought it was Venus. Jupiter is second only to Venus in brightness, but where it is now, opposite the sun in the sky, is a place Venus never can be because its orbit is closer to the sun than the earth. Jupiter is bright because it is big. It’s 5 times earth’s distance from the sun, so sunlight is diluted by a factor of 25 by the inverse square law. It’s 11 times the earth’s diameter. Square that, and its surface area is roughly 120 times that of the earth, so it reflects more light totally than Venus but appears somewhat fainter because it’s much farther than Venus. Volume wise Jupiter is 1,300 times the volume of the earth, but is only 318 times as massive as the earth.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
11/04/11 – Ephemeris – GTAS activities this weekend plus fall back
Friday, November 4th. The sun will rise at 8:23. It’ll be up for 10 hours and 3 minutes, setting at 6:27. The moon, 2 days past first quarter, will set at 3:23 tomorrow morning.
This evening the Grand Traverse Astronomical Society will be holding its monthly meeting at Northwestern Michigan College’s Rogers Observatory at 8 p.m. This evening we will have a special program by the student astronomers of NMC. And tomorrow night there will be a public viewing night from 8 to 10 p.m. with Jupiter and the moon as the featured targets if it will be clear. You can never tell if it’s going to be clear or cloudy until its time to observe, especially this year. The observatory is located south of Traverse City on Birmley Road between Garfield and Keystone Roads. Tomorrow night also we fall back by turning our clocks back one hour as standard time resumes. It’s going to be a lot darker in the evenings now.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
11/03/11 – Ephemeris – The moon tonight
Thursday, November 3rd. The sun will rise at 8:22. It’ll be up for 10 hours and 6 minutes, setting at 6:28. The moon, 1 day past first quarter, will set at 2:21 tomorrow morning.
In a telescope the moon will present some interesting features and craters. They will be seen near the terminator, the sunrise edge of the moon, where the shadows are longest. The moon is gray on gray, so the best way to see detail is by shadow. At the top or north end of the moon is a mountainous arc called the Alps. Mountain ranges on the moon are names after earthly mountain ranges. Cutting through the range is a fault called the Alpine Valley. Along the Alps at the terminator a crater will be coming into view this evening. It is the crater Plato. It is sometimes called a walled plain, since its floor is flat, or rather is slightly convex conforming to the shape of the lunar sphere. It’s cool watching the shadows of the walls recede as the sun rises.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Moon 1 day after first quarter. Created using Virtual Moon Atlas
11/02/11 – Ephemeris – Where are the planets this week?
Wednesday, November 2nd. The sun will rise at 8:21. It’ll be up for 10 hours and 9 minutes, setting at 6:30. The moon, at first quarter today, will set at 1:17 tomorrow morning.
Well it’s Wednesday and time again to take a look at the whereabouts of the bright planets. The planet Venus is still rather close to the sun in the evening setting 55 minutes after the sun and not really visible. Jupiter is now the prominent planet of the evening sky located in the east and is seen against the stars of the constellation Aries. It will pass due south at 1:05 a.m. In a telescope it will be accompanied by its 4 brightest moons. The moons and planetary features change from night to night and sometimes while you watch. Mars will rise at 1:46 a.m also in the east northeast and is moving between the constellations of Cancer and Leo. Mars is 145 million miles away and closing now ti will be closest to the earth March 3rd next year.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
11/01/11 – Ephemeris – Preview November Skies
Tuesday, November 1st. The sun will rise at 8:19. It’ll be up for 10 hours and 11 minutes, setting at 6:31. The moon, 1 day before first quarter, will set at 12:11 tomorrow morning.
Let’s look at the skies for the month of November. The sun is still moving south rapidly. Daylight hours in the Interlochen/Traverse City area and will drop from 10 hours and 11 minutes today to 9 hours 6 minutes on the 30th. The altitude, or angle, of the sun above the southern horizon at local noon will be at 30 degrees today and will descend to 23 and a half degrees on the 30th. The altitude of the sun in the Straits area will be a degree lower. Local noon, this month after we go back to standard time, will be about 12:30 p.m. Right now the planet Jupiter is rising in the east in the evening and Venus will soon be seen in the evening twilight. The Leonid meteor shower will be at its peak on the morning of the 18th.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
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.
10/28/11 – Ephemeris – The Great Andromeda Galaxy
Friday, October 28th. The sun will rise at 8:14. It’ll be up for 10 hours and 23 minutes, setting at 6:37. The moon, 2 days past new, will set at 7:53 this evening.
The Great Andromeda Galaxy is the closest large spiral galaxy to our own Milky Way Galaxy. It’s visible to the unaided eye in the east off the left star of the Great Square of Pegasus. Move left two stars and up two stars to the fuzzy spot. That is the heart of a galaxy that’s actually 6 moon diameters wide. It’s close too as galaxies go, only two and a half million light years away. Andromeda appears to be be somewhat larger than our galaxy, though may be less massive than the Milky Way because our galaxy seems to have more dark matter. It is approaching us at somewhat less than 100 miles per second, and will collide with the Milky Way in four or five billion years, about the time the sun will begin to bloat toward a red giant. Mark those down on your calendar.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Great Andromeda Galaxy (M31). Image taken by Scott Anttila.
The Constellation Andromeda. Created using Stellarium.
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.
10/26/11 – Ephemeris – Where are the bright planets this week?
Wednesday, October 26th. The sun will rise at 8:11. It’ll be up for 10 hours and 28 minutes, setting at 6:40. The moon is new today, and won’t be visible.
Well it’s Wednesday and time again to take a look at the whereabouts of the bright planets. The planet Venus is still rather close to the sun in the evening setting 48 minutes after the sun and not really visible. Jupiter is now the prominent planet of the evening sky located in the east and is seen against the stars of the constellation Aries. It will pass due south at 1:36 a.m. 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. The moons and planetary features change from night to night and sometimes while you watch. Mars will rise at 1:54 a.m also in the east northeast and is moving between the constellations of Cancer and Leo.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
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
