Archive
12/20/2012 – Ephemeris – Winter starts tomorrow morning.
Ephemeris for Thursday, 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, at first quarter today, will set at 1:51 tomorrow morning.
Tomorrow morning at 6:12 a.m. The sun will pass through the point where is appears the farthest south. We call it the winter solstice, or winter sun stand still. If you are measuring the shadow of the sun cast by a stick at noon, tomorrow will be the date of the longest noon time shadow. The ancients, who were not too sure the sun would come back partied big time as the sun stopped the southern progress and began to head back north. This was and is a big festival time featuring lots of lights, be it candles, torches, the burning of the yule log and Christmas lights. For those in the southern hemisphere they are celebrating the summer solstice. In any case our winter is the shortest season.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Noon in Michigan at the winter solstice. Created using Celestia.
To keep the earth large enough, I’ve had to move in to 10 earth radii, so Michigan at the top is a bit closer to the limb than it is to the sun. The vantage point is over the Tropic of Capricorn, 23 1/2 degrees south latitude. The short daylight hours and low sun angle hasn’t caught up to us yet. The coldest days are expected in January.
12/19/2012 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, December 19th. The sun will rise at 8:15. It’ll be up for 8 hours and 49 minutes, setting at 5:04. The moon, 1 day before first quarter, will set at 12:48 tomorrow morning.
Let’s check out the planets for this week. Mars can be seen low in the southwest. It will set at 7:04 p.m. The same as last week because sunrise times are increasing and Mars is starting to move northward. The sun will eventually catch up with it. Even before you can spot Mars, bright Jupiter will be visible in the east. Jupiter is located in the constellation of Taurus in the southeast in the evening. It will transit or pass due south at 11:15 p.m, and will set at 6:47 a.m. Jupiter is a wonderful sight in telescopes with its cloud bands and its moons which change positions each night. Saturn will be the next planet to rise at 4 a.m. in the east southeast. It’s located in eastern Virgo. Venus will rise at 6:20 and is below and left of Saturn.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter and the winter stars in the east southeast at 9 p.m. December 19, 2012. Created using Stellarium.
Saturn, Venus and the star Spica low in the east southeast at 6:45 a.m., December 20, 2012. Created using Stellarium.
12/17/2012 – Ephemeris – Were the planetary conjunctions of 3 and 2 BC the Star of Bethlehem?
Ephemeris for Tuesday, December 18th. The sun will rise at 8:14. It’ll be up for 8 hours and 49 minutes, setting at 5:03. The moon, 2 days before first quarter, will set at 11:43 this evening. | For over 400 years astronomers have wondered and looked through ancient Chinese records, ran the positions of planets back 2000 years, and still no one knows for sure what the Star of Bethlehem really was, but here’s my favorite scenario. On August 13th of 3 BC Jupiter and Venus briefly merged in the pre-dawn skies against the constellation of Leo the lion. A month later Jupiter was in conjunction with Regulus the bright star in Leo, the little king star. Then 9 months later, after sunset on June 16th of 2 BC the two planets again joined as one in Leo. The king of the planets twice mating with Venus as Ishtar, the Babylonian goddess of fertility, against the constellation of the lion signifying Judah from Genesis? The Magi not being Jewish might have found meaning in all that.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Animation of the Jupiter-Venus conjunction of August 3, 3 BC. in the morning twilight. Created using Stellarium.
Click on the image to enlarge and show the animation. Jupiter is rising while Venus, the brighter one, is heading back to the sun. Jupiter will seem to mate with Venus. 9 months later, the human gestation period their paths seem to cross again.
June of 2 BC just after sunset Jupiter and Venus again cross paths. Created using Stellarium.
Click on the image to enlarge and show the animation.
12/17/2012 – Ephemeris – The Star of Bethlehem: Who were the Magi?
Ephemeris for Monday, December 17th. The sun will rise at 8:14. It’ll be up for 8 hours and 49 minutes, setting at 5:03. The moon, 3 days before first quarter, will set at 10:36 this evening.
The Star of Bethlehem is one of the great mysteries of Christmas. The Chinese of that time were the only ones that recorded the happenings in the heavens. There were no bright stars that appeared near the time of Christ’s birth. That leads us to the Magi themselves, if that’s who they were. Magi were astrologer priests of the Zoroastrian religion in Persia. They saw signs in the positions of the planets that would go unnoticed to the Jews to which astrology was forbidden. Conjunctions where two or more planets gathered together were the most powerful of these configurations. There was a triple conjunction of Jupiter and Saturn in seven BC that’s the most famous, but I have another set of conjunctions in mind to tell you about tomorrow.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
12/14/2012 – Ephemeris – The constellation of the river Eridanus
Ephemeris for Friday, December 14th. The sun will rise at 8:12. It’ll be up for 8 hours and 50 minutes, setting at 5:02. The moon, 1 day past new, will set at 6:58 this evening.
There is a long and sinuous constellation that’s part of the winter sky. It is Eridanus, which depicts a river. The river starts near the lower right corner of Orion, near the bright star Rigel and flows to the right then down near the southern horizon, then it meanders below the horizon. One has to travel to the far southern United States or even farther south to see the southern terminus of the river, the bright star Achernar. Writers over the ages have seen here the Nile and the earth circling river Ocean of the flat earth days. One of its stars is close to us and famous. It’s Epsilon Eridani host to at least two large planets and the home to the fictional Mr. Spock and other Vulcans of the Star Trek franchise. Trouble is the star is too young and any earth-like planets would be in unstable orbits.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The constellation Eridanus the river, both above and below the horizon. Created using Cartes du Ciel.
12/13/2012 – Ephemeris – The Geminid meteor shower reaches its peak tonight.
Ephemeris for Thursday, December 13th. The sun will rise at 8:11. It’ll be up for 8 hours and 51 minutes, setting at 5:02. The moon is new today, and won’t be visible.
Tonight will be the peak of the Geminid meteor shower. This is one of the most active showers of the year. Some say it’s even more active than the Perseid meteor shower of August with up to 100 meteors or shooting stars visible an hour. They will seem to come from near the star Castor in the constellation Gemini which is rising high towards midnight. The moon will not interfere because it’s new. The radiant point is highest at 2 a.m. But will be in the sky from 8 p.m. on All you’ll need then is clear skies. If it does clear up, make sure you dress warmly. It will take up to 10 minutes or even more for your eyes to get accustomed to the darkness to be able to see the meteors. The meteors are related to a body called Phaethon, a dead comet nucleus.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Geminid Radiant
12/12/2012 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, December 12th. The sun will rise at 8:10. It’ll be up for 8 hours and 51 minutes, setting at 5:02. The moon, 1 day before new, will rise at 8:18 tomorrow morning.
Let’s check out the planets for this week. Mars can be seen low in the southwest. It will set at 7:04 p.m. The planetary action will have already picked up on the other side of the sky. Jupiter is located in the constellation of Taurus on the southeast in the evening. It will transit or pass due south at 11:47 p.m, and will set at 7:19 a.m. Saturn will be the next planet to rise at 4:24 a.m. in the east southeast. Venus will rise at 6:02 and is below and left of Saturn. Mercury will rise at 6:36 a.m. Below and left of Venus. A half an hour later it should be high enough to spot. The three planets will appear in a straight line and nearly equally spaced. After a few days Mercury will not be visible again until next February.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars low in the southwest at 6:15 p.m. on December 12, 2012. Created using Stellarium.
Jupiter and the winter stars at 9 p.m. December 12, 2012. Created using Stellarium.
Jupiter with its Great Red Spot November 18, 2012 by Scott Anttila.
Jupiter with Callisto above, Ganymede and its shadow below on December 6, 2012 by Scott Anttila, Click to enlarge.
Saturn, Venus and Mercury at 6:45 a.m. ay December 13, 2012. Created using Stellarium.
12/11/2012 – Ephemeris – The Pleiades and Hyades star clusters
Ephemeris for Tuesday, December 11th. The sun will rise at 8:09. It’ll be up for 8 hours and 52 minutes, setting at 5:02. The moon, 2 days before new, will rise at 7:13 tomorrow morning.
At 8 to 9 p.m. The constellation of Taurus the bull rises higher in the east to southeast. Taurus contains two bright clusters of stars. The most famous of these is the Pleiades, also known as the Seven Sisters. The other is a letter V shape that is the face of Taurus, the Hyades. In the Greek mythology they are half-sisters of each other, all fathered by the Titan Atlas. They are apparently fleeing from the giant Orion rising in the east. The Pleiades are the younger of the two star clusters, and there has been some problem in estimating their distance. They could be from 390 to 460 light years away. The distance to Hyades is much better known at 153 light years. It was the star cluster upon which greater distances could be measured.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Hyades (lower left) and the Pleiades (upper right). My photograph from many years ago.
12/10/2012 – Ephemeris – Saturn will be above the moon this morning.
Ephemeris for Monday, December 10th. The sun will rise at 8:08. It’ll be up for 8 hours and 53 minutes, setting at 5:02. The moon, 3 days before new, will rise at 6:01 tomorrow morning.
This morning, if it’s clear look eastward at the moon and planets. The planet just above the moon is the planet Saturn. Farther below and to the left is the brilliant planet Venus. Those with good eyesight or binoculars might spot tiny Mercury. In the morning we get a preview in the stars of a season or two ahead from what we see in the evening. Orion, which is rising in the east in the early evening is seen setting in the west at 7 in the morning. The spring stars are now reigning in the morning sky, and a few summer are peeking above the eastern horizon, pretty much drowned out by the morning twilight. Next spring Saturn will be little moved from its current position, It takes it a bit less than 30 years to orbit the sun.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Saturn and the moon low in the southeast at 6:30 a.m. on December 10, 2012. Created using Stellarium.
Tomorrow morning the moon will pass below Venus. See this animation below.
Mercury animation from December 4 to thru 12, 2012. Created using Stellarium
12/07/2012 – Ephemeris – Search for the Star of Bethlehem tonight!
Ephemeris for Friday, December 7th. The sun will rise at 8:06. It’ll be up for 8 hours and 56 minutes, setting at 5:02. The moon, 1 day past last quarter, will rise at 2:19 tomorrow morning.
The Search for the Star of Bethlehem, will be presented at this evening’s meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers Observatory starting at 8 p.m. This is my biennial presentation. We’ll check out the Biblical passages that mention the star, Johannes Kepler’s discovery that started the search some 1600 years later, ancient Chinese records, ancient writers all contribute to the quest. Thanks to Kepler, Newton, Einstein and others plus the power of computers we can go back and see the skies, and computer generated recreations of planet positions to see what the star might have been. Starting at 9 p.m. Is our December star party at the observatory. All are welcome.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Title slide for the program.
