Archive
04/17/2012 – Ephemeris – The constellation of Coma Berenices as a star cluster
Ephemeris for Tuesday, April 17th. The sun rises at 6:54. It’ll be up for 13 hours and 36 minutes, setting at 8:30. The moon, half way from last quarter to new, will rise at 5:23 tomorrow morning.
Looking to the southeast these nights can be found the dim constellation of Coma Berenices, or Berenice’s hair. It’s located about half way from the horizon to the zenith. It’s best seen on a moonless night as a sprinkling of faint stars that look like strands of hair. It is a star cluster some 270 light years away, the second closest star cluster to the earth, the closest being the Hyades the marks the face of Taurus the bull, at about 153 light years, which is below, left of Venus tonight in the west. Coma Berenices is located at an odd spot for an open or galactic star cluster. It’s at the pole of the milky way, as far from the milky band as you can get. Most galactic star clusters are close or in that band. However due to its closeness Coma Berenices is abreast of us. as we orbit the center of the Milky Way.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Coma Berenices via Stellarium
Only one star of the three denote the constellation is part of the Coma Berenices star cluster, which appears to trail from the top star.
04/16/2012 – Ephemeris – Saturn a day after opposition
Ephemeris for Monday, April 16th. The sun rises- at 6:55. It’ll be up for 13 hours and 33 minutes, setting at 8:29. The moon, 3 days past last quarter, will rise at 4:59 tomorrow morning.
Saturn was in opposition from the sun yesterday. That means that Saturn was opposite the sun in the sky. That means that Saturn was closest to the earth at 811 million miles. The difference from today’s distance isn’t worth mentioning. Saturn, being 9 and a half times the earth’s distance from the sun doesn’t make much difference in Saturn’s apparent size, whether we view it from the nearest point in our orbit of the farthest. Saturn, which is just left of the bright bluish star Spica in the southeast in the evening, is definitely not star-like in binoculars, but a 20 power spotting scope will just bring out Saturn’s rings elliptical nature. Those rings will open up for the next four years, so the rings at their narrowest part will be as wide as the planet.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Image of Saturn created with Cartes du Ciel showing current ring tilt.
04/13/2012 – Ephemeris – The story of Boötes and Ursa Major
Ephemeris for Friday, April 13th. The sun will rise at 7:01. It’ll be up for 13 hours and 24 minutes, setting at 8:25. The moon, at last quarter today, will rise at 3:37 tomorrow morning.
Rising higher 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, much higher in the east north east. 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 (Ursa Major) 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
Boötes & Ursa Major at 10 p.m. on April 13, 2012. Created using Stellarium.
The constellation artist for Stellarium has Boötes facing the wrong way for my story to work. Officially Boötes is the herdsman.
04/12/2012 – Ephemeris – The constellation Virgo the virgin
Ephemeris for Thursday, April 12th. The sun will rise at 7:02. It’ll be up for 13 hours and 21 minutes, setting at 8:24. The moon, 1 day before last quarter, will rise at 3:02 tomorrow morning.
Tonight in the sky: to the left of the constellation of Leo the lion, which lies in the south at 10 p.m. is the next constellation of the zodiac: Virgo the virgin, seen in the south southeast. Virgo is a large constellation of a reclining woman holding a stalk of wheat. The bright star in the center of the constellation, Spica, is the head of that spike of wheat; and as such ruled over the harvest in two of Virgo’s guises as the goddesses Persephone and Ceres. The planet Saturn is also in Virgo this year to the left of Spica. Virgo is also identified as Astraea the goddess of justice. The constellation of Libra, the scales, is found just east of her a couple of hours later, not yet risen at 10 p.m. Early Christians saw Virgo as the Virgin Mary.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Virgo 2012. Created using Stellarium.
04/11/2012 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, April 11th. The sun will rise at 7:04. It’ll be up for 13 hours and 18 minutes, setting at 8:23. The moon, 2 days before last quarter, will rise at 2:19 tomorrow morning.
Let’s see what’s happening with the bright planets for this week. Venus and Jupiter have separated quite far apart in the western sky after sunset. Jupiter is below Venus, the brighter planet. Jupiter will set at 10:22 p.m. followed by Venus at 12:37 a.m. Venus is 55.2 million miles away and closing. Mars is high in the southeast to south in the evening with its unmistakable bright reddish color. It’s in the constellation Leo the lion now. It is 75 million miles and moving away. Mars will pass due south at 10:46 p.m. and will be setting in the west at 5:40 a.m. Saturn will rise at 8:30 p.m. just to the left of the bright star Spica in the east southeast. It will pass due south at 2:02 a.m. All the bright planets except Mercury are now visible in the evening.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Sky and planets at 9:20 p.m. April 11, 2012. Created using Stellarium.
04/10/2012 – Ephemeris – The story of Corvus the crow
Ephemeris for Tuesday, April 10th. The sun will rise at 7:06. It’ll be up for 13 hours and 15 minutes, setting at 8:21. The moon, 3 days before last quarter, will rise at 1:27 tomorrow morning.
The small constellation of Corvus the crow is located low in the southeast at 10 this evening. It’s made of 5 dim stars, but the pattern is a distinctive distorted box with two stars at the upper left marking that corner. To the right is a fainter constellation of a thick stemmed goblet called Crater. Both appear above the long constellation of Hydra the water snake who is slithering just above the southern horizon.. In Greek mythology Corvus, then white, was the god Apollo’s pet. Apollo once bid Corvus to take a cup and fetch him some water. Corvus however dallied and waited for an unripe fig to ripen. Corvus grabbed a snake and returned with a story as to how the snake had delayed him. The angry Apollo turned the crow and all crows to this day black.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Hydra the Water Snake at 10 p.m. on April 9th, 2012. Created using Stellarium.
Yesterday’s chart, but little change. OK, it for 9:56 p.m. Check out Corvus the crow and Crater the cup. Sextens the sextant came later. The Greeks didn’t have them.
04/09/2012 – Ephemeris – The constellation of Hydra the water snake
Ephemeris for Monday, April 9th. The sun will rise at 7:08. It’ll be up for 13 hours and 12 minutes, setting at 8:20. The moon, 3 days past full, will rise at 12:25 tomorrow morning.
In the south and southeastern sky at 10 p.m. can be found the constellation of Hydra the water snake. Unlike the monster of the same name this Hydra has but one head, which is its most distinctive part. At 10 p.m. look to the south. The head of Hydra is located below a line from the constellation Leo the Lion in the south where Mars is now and Gemini high in the west southwest. Hydra’s head is a small but distinctive group of 6 stars that make a drooping loop to the right. The rest of Hydra wends its way just above the southern horizon ending under Virgo below the star Spica and Saturn this year. Some delineations of Hydra have the tail tickling the constellation Libra which is just about to rise at that time.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Hydra the Water Snake at 10 p.m. on April 9th, 2012. Created using Stellarium.
04/06/2012 – Ephemeris – Meteorites and a Star Party this weekend
Ephemeris for Good Friday, Friday, April 6th. The sun will rise at 7:13. It’ll be up for 13 hours and 3 minutes, setting at 8:16. The moon, at full today, will rise at 8:38 this evening.
The Grand Traverse Astronomical Society will meet tonight at 8 p.m. at the Northwestern Michigan College’s Rogers Observatory. Following will be a public star party featuring the moon, Venus, Jupiter, Mars and Saturn. This year the first viewing night of the month will come at the end of the society meeting at 9 o’clock. Come for both. From April to September there will be a second star party at the observatory, plus other star parties and other events in the area. The presenter for the meeting tonight will be member Joe Brooks. He will bring his extensive meteorite collection and talk about them and where they come from. The observatory is located on Birmley Road between Keystone and Garfield roads.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
04/05/2012 – Ephemeris – Seeing Dark Matter
Ephemeris for Thursday, April 5th. The sun will rise at 7:15. It’ll be up for 13 hours exactly, setting at 8:15. The moon, 1 day before full, will set at 6:44 tomorrow morning.
Astronomers have come to the realization that what we see in the universe as normal matter is only four percent of the universe’s mass and energy. Dark matter makes up about 23 percent, while the totally mysterious dark energy makes up the rest. We do have some clues about what dark matter is. We still can’t see it. However we can detect its presence in distant galaxy clusters. Since whatever it is has mass, it can distort space-time, and the path of light that passes through it. We can detect it because it distorts the shapes of more distant galaxies we see through it. The amount and shape of the distortions point to the location and densest of the dark matter. Whatever this stuff is it has mass, and has and is affected by gravity, but apparently doesn’t interact with ordinary matter of itself for that matter.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
04/04/2012 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, April 4th. The sun will rise at 7:17. It’ll be up for 12 hours and 57 minutes, setting at 8:14. The moon, 2 days before full, will set at 6:13 tomorrow morning.
Let’s see what’s happening with the bright planets for this week. Venus and Jupiter are separating in the western sky after sunset. Jupiter is way below Venus, the brighter planet. Jupiter will set at 10:41 p.m. followed by Venus at 12:28 a.m. It is 59.6 million miles away and closing. Mars is in the southeast to south in the evening with its unmistakable bright reddish color. It’s in the constellation Leo the lion now. It is 71.1 million miles and moving away. Mars will pass due south at 11:16 p.m. and will be setting in the west at 6:10 a.m. Saturn will rise at 9:01 p.m. just to the left of the bright star Spica in the east southeast. It will pass due south at 2:31 a.m. All the bright planets except Mercury are now visible in the evening.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Animation of the planets and moon at sunrise for April 2012
Click on the images to enlarge.
Animation of the planets and moon at sunset for April 2012
Bob Moler's Ephemeris Blog 