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This is the Classical Astronomy Update, an email newsletter especially
for Christian homeschool families (though everyone is welcome!)
Please feel free to share this with any interested friends.
IN THIS UPDATE:
- Announcements
- The Old Schoolhouse Christmas Special!
- Excellent Moon Poster
- Our Latest Comet Sighting
- Seasonal Skies
- Orion Rising
- Geminid Meteors
- Dance of the Planets
Then Paul stood in the midst of Mars' hill, and said, Ye men of Athens, I
perceive that in all things ye are too superstitious. -Acts 17:22
Welcome to the Classical Astronomy Update!
Hello Friends,
Snow has finally arrived to wind-swept shores of the Great Lakes! It's beginning to look a lot like Christmas! I'm a winter lover and make no apologies! I love watching the snow fall and love taking winter hikes with the snow crunching beneath my boots. I also love to ski and stay out in the cold for 5-6 hours at a time. Chapped, windburned cheeks don't bother me a bit! If you hate the snow and love living somewhere warm, God bless you! We'll keep the snow and let you keep your hurricanes and earthquakes, thank you very much!
Now that December is here, the brilliant constellation Orion returns again to the evening skies. This year the Orion sky has a special guest -- the bright red planet Mars. In this Update we'll learn about this apparition of Mars after we explain how to spot Orion and his neighbors.
Announcements
The Old Schoolhouse Christmas Sale
 Our friends at The Old Schoolhouse magazine are having a Christmas Sale
- buy a new one-year subscription or renew an existing one, and give a one-year gift subscription to a friend for only $5.00. This is a great way to send a little encouragement to your homeschool friends. It's cheaper than giving a book or a candle, or even the price of eating out for lunch! And it's a Christmas gift that keeps on giving throughout the year!
Though we like all the homeschool magazines, my wife and I can truly say that we like The Old Schoolhouse the best. It is a warm and friendly magazine that offers a great variety of practical and interesting information for homeschool families. Also, their companion site HomeschoolBlogger.com is a wonderful online community for homeschoolers. If you haven't already done so, please check out The Old Schoolhouse.
Excellent Moon Poster
I recently received a really excellent poster of the Moon. This very large and colorful poster includes the names of the Moon's craters and interesting information such as the landing sites of the Apollo missions and also unmanned space probes.
The border of the poster includes a number of sidebars with interesting information, such as the librations of the Moon and data signatures that might indicate water on the Moon that can be used by future lunar colonists. There is a small section about secular lunar origin theories. This box is interesting to me as a Christian in that it is very candid about the various problems with each of the evolutionary theories of the Moon's origin. This can encourage a healthy, informed skepticism of materialistic origin theories. There are some other evolutionary references on the poster, but it is otherwise a very useful guide to the visible surface of the Moon.
This poster is available from www.moonposter.ie and is very affordably priced at 12.95 Euros (about $16.00 US) with online ordering through PayPal. Shipping is included to anywhere in the world. It's really a bargain and would make a great addition to your homeschool, particularly if you have a family telescope and would like to learn the Moon's craters.
Our Latest Comet Sighting
Comet Holmes (aka "Holly's Comet") isn't very visible these days from our light-polluted urban neighborhood. But I was out at Boy Scout camp last week with our sons, far from the city lights, and we were all pretty amazed by how easy it is to see with the unaided eye.
Through the binocs, it was easy to see that the comet now appears "egg-shaped." This is because the Earth has moved in its orbit and is no longer lined up with the comet, so we can now see it from a side angle. Though a "tail" is not visible, it seems pretty obvious that the comet is essentially a big cloud of wispy stuff that is being somewhat "blown back" by the Sun.
To see what I mean, check out this nifty shot of Comet Holmes from NASA's Astronomy Picture of the Day web site, which is a site worth bookmarking and visiting daily if you like this sort of thing.
Here's another recent movie from this site showing the analemma -- the figure-8 pattern the Sun traces out in the sky as it moves through the seasons, as found on globes made by the George F. Cram Company. This movie is a reprise of the famous year-long, multi-exposure photo taken by Sky & Telescope editor Dennis DiCicco in 1979. (Hat tip to Jim Cook of New Curlton, Maryland for the link.)
An explanation of the analemma and its usefulness is scheduled for the sequel of our Signs & Seasons curriculum (if it ever gets finished!) In the meantime, if anyone wants to learn more about the analemma, drop me an email and I'll see if we can fit it into the Update sometime in '08.
Seasonal Skies
Orion Rising
Long-time readers of the Update know that we like to discuss the constellation Orion! In fact, Orion is the official constellation of the Ryan Family! We gave one of our sons the middle initial "O" just so he could be an "O. Ryan"!!! So we are always happy in this time of year when Orion is once again coming into view in the evening sky.
In the early evenings of December, the bright star Capella is seen rising in the northeast. For northern observers, Capella heralds the rising of the constellation Orion. If you are fortunate enough to live near under a clear, dark sky, you can also see near Capella the bright star cluster called The Pleiades. This famous cluster of seven stars is mentioned in many great works of literature down through the centuries. And, like Orion, it is among the few celestial objects named in the Bible:
Canst thou bind the sweet influences of Pleiades? Or loose the bands of Orion? - Job 39:31
As the evening twilight darkens to full night, Capella and the Pleiades rise higher in the night sky. Soon the bright star Aldebaran can be seen above the tree tops. Aldebaran is a reddish-orange colored star, and is considered to be the bright red eye of the Bull in the constellation Taurus. By about 8:00 PM around Christmas time, the stars of Taurus are high enough in the sky so that a "V" shape of faint stars can be made out -- a configuration of stars that represent the "head" of the Bull. Taurus is one of those remarkable constellations that actually resemble the object for which it is named!
And during the early evenings around the new year, the brilliant constellation Orion can be seen rising above the treetops in the early evening after sunset. As we've mentioned numerous times in previous Updates, Orion is the bright, starry hunter, the brightest constellation in the sky, formed of some the brightest stars. Orion is particularly notable for his "Belt," a straight line of three bright, closely spaced stars, right along the middle of the constellation.
In addition to the Bible, Orion has been mentioned in literature throughout all history, from the Greek poet Homer til recent times. Here's a clear description of the stars near Orion that can be seen rising in the current season -- including the cluster of the Pleiades, red Aldebaran and Orion's Belt -- from a great work of 20th century literature:
Away high in the East swung Remmirath, the Netted Stars, and slowly above the mists red Borgil rose, glowing like a jewel of fire. Then by some shift of airs all the mist was drawn away like a veil, and there leaned up, as he climbed over the rim of the world, the Swordsman of the Sky, Menelvagor with his shining belt. The Elves all burst into song. - from "The Fellowship of the Ring" by J.R.R Tolkien
In this season, Orion is high in the sky at midnight. Over the winter, with the seasonal advance of the constellations, Orion will reach the middle of the sky earlier each month, and will be high in the sky after sunset by March. Since the stars near Orion are so bright and conspicuous, winter is the best time to begin learning the constellations, since you can begin with Orion and work your way east throughout the advancing seasons.
Detailed information for following the annual progression of Orion is found in our Signs & Seasons curriculum.
Geminid Meteors
The Geminid meteor shower runs each year from December 7 through December 15. The peak night for seeing the Geminids is the Thursday evening December 13 through Friday morning December 14. The Geminids are usually considered the second best meteor shower of the year in terms of actual meteor count. However, your chances of seeing more meteors might be better with the Geminids.
The radiant of this shower is in the constellation Gemini which rises in the early evening with Orion and is above the horizon all night. Also, nights are longer for us northern dwellers this time of year, unlike August when the Perseids are seen. Also, in 2007, a waxing crescent Moon will set in the early evening, and will not cast its glow over the night sky.
The biggest problem you can expect is clear skies! Those of here on the mist-enshrouded shores of the Great Lakes don't see the Geminids very often! However, when the nights are clear around here, a crisp, frosty night has very low humidity and offers an inky black sky, even from the city.
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Dance of the Planets
The bright planet Mars has been visible in the morning sky since summer, hovering around the constellations near Orion. Following the seasonal advance of the stars, Mars and rest of the neighborhood of Orion have now progressed into the evening sky. As you observe Orion rising in the east in the evenings of December, you can't miss the ruddy glow of Mars as passes through the stars of the constellation Gemini.
The current season is one of your better opportunities to observe the retrograde motion of Mars. Normally, the Sun, Moon, and visible planets all appear to move steadily toward the east. However, at certain times, the superior planets -- Mars, Jupiter, and Saturn -- will all appear to move backwards through the constellations. As the superior planets approach opposition, the time when they are in the opposite part of the sky from the Sun, they slow down and stop, and then reverse their easterly direction and moving toward the west. After this time, they slow and stop again, resuming their easterly course.
These retrogradations baffled the ancient astronomers who believed that these bodies revolved around the Earth in their cycles. This reverse motion was only adequately explained by the heliocentric cosmology of Mikloaj Kopernik. It is now understood that the superior planets are actually outer planets in orbits beyond the orbit of the Earth. The apparent retrograde motion is a result of the faster-moving Earth passing the slower outer planets as they all move in their respective orbits.
As the Earth overtakes and passes these planets, the line of sight to the background stars shifts, creating a difference in parallax. (Look up that word!) This is a similar idea to how trees and telephone poles appear to shift position compared to more distant objects as you pass them by in a car.
(((((ACTIVITY))))))
To observe the "parallax view," hold out your thumb at arms length in line with a distant object, across the room or at a greater distance outside. Look at your thumb while first covering one eye and then the other eye. Note how the line of sight between your thumb and the distant object changes depending on which eye you're looking with. A similar phenomenon is visible in the sky over a period of months as we gaze at the superior planets approaching opposition.
This time around, the retrograde motion of Mars began on November 15, 2007. The opposition of Mars will occur on December 24, 2007, when Mars rises as the Sun sets. The retrogradation will continue until January 30, 2007. Opposition always occurs in the middle of the retrogradation.
If you carefully note the position of Mars over the next month and a half, you will see it steadily moving away from the twin stars of Gemini, Castor and Pollux. Mars will move west over Orion's head, and approach a brighter star called Elnath at the "horn of the Bull" in the constellation Taurus. Afterwards, Mars will resume its easterly motion and by early April again reach the place in Gemini where it began its retrogradation. By this time, Orion and Gemini will be sinking toward the sunset, and Mars will be visible in the western sky in the early evening.
For detailed information with illustrations on the retrograde motion and all the apparent motions of the planets, check out Signs & Seasons, our Classical Astronomy curriculum.
Coming in future Classical Astronomy Updates:
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The winter solstice approaches for celestial observers in the northern hemisphere.
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A close conjunction of the Moon with Mars will be visible on the night of December 23/24, 2007. This should be an astounding sight!
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Mars will rise earlier in the morning and will soon be visible in the evening skies, approaching opposition on December 24, 2007.
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There will be a multiple conjunction of the Moon, Venus, and Jupiter on the morning of February 4, 2008. This will be a wowzer!
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There will be a total eclipse of the Moon on the night of February 20/21, 2008. It's not too early to start praying for clear skies!
Til next time, God bless and clear skies!
-jay
The Ryan Family
Cleveland, Ohio, USA
When I consider thy heavens, the work of thy fingers, the moon and
the stars, which thou hast ordained, what is man that thou art
mindful of him? and the son of man, that thou visitest him?
- Psalm 8:3,4, a Psalm of David
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