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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
- 2009 Old Farmer's Almanack
- New Products for Online Ordering
- Any Questions?
- Dance of the Planets
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- Rosh Hoshanah
- The Crescent Moon and Planets
- Astronomy Topics
Fear before him, all the earth: the world also shall be stable, that it be not
moved. Let the heavens be glad, and let the earth rejoice: and let men
say among the nations, The LORD reigneth. Let the sea roar, and
the fulness thereof: let the fields rejoice, and all that is therein.
- 1 Chronicles 16:30-32
Welcome to the Classical Astronomy Update!
Hello Friends,
The seasons have finally turned here on the wind-blown shores of the Great Lakes. After a golden month from August through September, the clouds have returned, a familiar sign of fall to those of us here in the Great White North. As the days grow shorter and the leaves begin to change colors, the nip in the air foretells of even nippier air to come in the next season.
The annual cycle of the seasons is part of the LORD's creation, and will remain a normal part of life on Earth:
While the earth remaineth, seedtime and harvest, and cold and heat, and summer and winter, and day and night shall not cease. - Genesis 8:22
But this seasonal cycle is not simply a variation in the weather. Readers of the Update and our Signs & Seasons curriculum know that all seasonal changes are the result of the astronomical variations in the position of the Sun. The shortening of the days in autumn results in cooling of the Earth, leading to winter, just as the lengthening of the days in spring causes the Earth to warm again.
As simple as these cycles may seem to be, learning to observe the astronomical signs of the seasons can add a depth and appreciation for the seasonal cycles of the plants and animals, and all aspects of the Creation.
Announcements
2009 Old Farmer's Almanac
The 217th edition of the Old Farmer's Almanac for 2009 is now available. This classic piece of Americana, continuously in print each year since 1792, remains one of the most accessible resources for Classical Astronomy information. Over 80 pages of astronomy information are included. The calendar pages include a daily list of Moon phases and lunar conjunctions with the visible planets. Also included is an article about the astronomer Johannes Kepler, for whom the 400th anniversary of his revolutionary work occurs in 2009.
The 2009 Almanac is especially notable for the article Is Global Warming on the Wane? by meteorologist and climatologist Joseph D'Aleo, co-founder of the Weather Channel. This article has generated a lot of buzz in the media and is a must-read for everyone who suspects that the Sun may play a dominant role in any observed climate change.
As usual, beware of the handful of astrology pages in the OFA. This unfortunate superstition is a late addition to the long tradition of this vintage publication, which never had any astrology during the 50 year run of OFA founding editor, Robert B. Thomas. I encourage everyone to overlook this silly inclusion to otherwise worthwhile publication.
The July/August 2008 issue of Homeschooling Today included my article The American Almanack Tradition. If you missed it, you can download a PDF of that issue.
New Products for Online Ordering from Fourth Day Press
Here we see Zippy, the official Fourth Day Press "watchcat," sleeping on the job in the Fourth Day Press "warehouse." Thanks for everyone's support of Signs & Seasons and our new companion workbook. But it seems that most everyone has made their curriculum purchases for this school year, and there's not much these days for Zippy to do.
(BTW, in addition to being our new "marketing director" and our son Sammy's "little brother," Zippy is a great pet, and always comes around to "say hi" when I'm working or reclining in our rec room. Zippy sure has great posuture, doesn't he?)
To give Zippy something to do, we've added a couple items to our Online Store, and we're also closing out some items from our old online store of a few years back. Here's some of the items, many of which would be great Christmas presents for the smaller kids in your family. For a complete list of all our currently available products, check out the main page and left sidebar in our Online Ordering page.
Eclipse Shades - nifty solar filters that allow you to safely look at the Sun.
Cycles - my little 32 page astronomy comic book.
Hugg-A-Planet - soft, plush globes, great for little ones! These are lots of fun!
Cassiodorus' Institutions - attention classical homeschoolers! This is a recent translation of the earliest Christian textbook, an important 5th century source for the Trivium and Quadrivium.
Thanks in advance for checking out our new online store!
Any Questions?
Once upon a time we used to get a lot of reader questions about Classical Astronomy. People would ask about stars and Moon phases and all manner of sightings in the sky. These topics were always inspiring and made it easy to write this newsletter. Some of our best articles came from detailed answers to reader questions. I don't know why, but these days we hardly get any questions anymore, and it's become hard to think up new stuff to write about in this newsletter without this important reader feedback.
If there's anything you'd like to know about sightings in the night sky or the history of astronomy, please drop a line and ask us a question. All I ask is that we not get questions about "modern astronomy" topics such as NASA space missions, black holes, theoretical cosmology and all that. Thanks!
Dance of the Planets
Rosh Hoshanah
The astronomical New Moon occurs when the Moon is invisibly aligned with the Sun as seen from the Earth. However, in the Jewish tradition, the "New Moon" is the first sighting of the crescent Moon in the evening sky. This sighting signifies the beginning of the month in the Jewish lunar calendar. Historically, the "official" sighting of the crescent Moon was one of the jobs of the Sanhedrin in Jerusalem.
The New Moon observance is referred to many times in the Old Testament:
Also in the day of your gladness, and in your solemn days, and in the beginnings of your months, ye shall blow with the trumpets over your burnt offerings, and over the sacrifices of your peace offerings; that they may be to you for a memorial before your God: I am the LORD your God. - Numbers 10:10
In the Hebrew Scriptures, the words for "Moon," "New Moon," and "month" are all similar and appear to either have nuanced meanings or are maybe even interchangeable. For example, the Hebrew word chodesh can be used for all these meanings, though the term Rosh Chodesh means "head of the month," and specifically refers to the official first sighting of the crescent Moon. Another word yareach or yerach is alternately translated in Scripture as "Moon" or "month."
There is one special Rosh Chodesh each lunar year called Rosh Hoshanah which means "head of the year" and indicates the start of the month Tishri. Rosh Hoshanah marks the start of the Jewish civil year and the beginning of the high holy days that end with Yom Kippur, the Day of Atonement. For more on Rosh Hoshanah, read this Wikipedia article.
In 2008, the astronomical New Moon was on September 29, when the Moon was aligned with the Sun. Rosh Hoshanah was the next day, September 30, when a very thin crescent Moon would have been sighted in the evening sky.
The Crescent Moon and Planets
During the waxing phases of early autumn, the Moon grazes the horizon as it increases from a thin crescent to a Full Moon. (For more on this and the "Harvest Moon" effect, see the article Approach of the Autumn Sky from our September 3, 2008 Update.)
In the days following Rosh Hoshanah, look for the waxing crescent Moon low in the southern sky. On Wednesday, October 1, the Moon will pass the fading planet Mars. You might not see that, but your chances are better of spotting the Moon the next night, Thursday, October 2, when it passes the dazzlingly bright planet Venus. Look for this pair low in the southwestern horizon in bright twilight after sunset.
The Moon will skim near the bright star Antares on the evening of Saturday, October 4. Our friends in Australia and the far east are best favored for this passing. But if you can't pick out that event, then you won't be able to miss when the First Quarter Moon passes that bright celestial blowtorch Jupiter on the evening of Tuesday, October 7. So mark your calendars and drop us a line if you see any of these for the first time!
Astronomy Topics
Midnight
Many today might think that midnight is an arbitrary time on the clock, an opposite to noon, which some people realize indicates the traditional time when the Sun is highest in the sky. However, like noon, midnight has its own precise astronomical definition. To the experienced observer, midnight can be observed in the night sky just as readily as the Sun at noon.
Midnight can be defined as the point in the sky diametrically opposite the Sun's position in the sky. As we see in Signs & Seasons, the Sun is always appears at some position along the ecliptic, a circle in the sky which corresponds to the plane of the Earth's orbit around the Sun. The circle of the ecliptic lies along a band of constellations in the night sky which lie along the plane of the solar system. These constellations are collectively known as the zodiac.
Anyway, the Sun's position along the zodiac can be inferred by observing the zodiac constellation just above the western horizon after sunset and the one above the eastern horizon before sunrise. The Sun's current position is "the one in the middle," the constellation invisibly below the horizon at these times. But this is not a very precise way to know the Sun's position, since we cannot directly observe the stars behind the Sun's bright rays.
The actual position of the Sun along the ecliptic can be inferred from finding the point in the sky opposite the Sun, i.e. the point in the sky that rises as the Sun sets in the evening, and sets in the morning as the Sun rises. This is the same point in the sky that reaches the meridian at midnight, when the Sun is at its lowest point below the horizon.
This is easy to find, since astronomical midnight occurs exactly twelve hours after the Sun reaches its highest point in the sky, when shadows are shortest, and when it hangs above the southern horizon. If one has a thorough knowledge of the constellations, one can spot the exact stars near the meridian twelve hours after noon, and from there conclude that the Sun is at the opposite point.
This method was explained by Isaac Watts, the great hymnist, who also was an enthusiastic amateur astronomer and wrote several popular books on astronomy:
If it be enquired, How can we know the Place of the Sun among the Stars, since all the Stars near it are lost in the Sun-Beams? 'Tis answered, that we can see plainly what Constellation or what Stars are upon the Meridian at Midnight, and we know the Stars which are exactly opposite to them, and these must be upon the Meridian (very nearly) the same Day at Noon; and thereby we know that the Sun at Noon is in the midst of them. So that when you have a Globe at hand on which the Stars are delineated, you find on what Degree of any Sign the Sun is on on a given Day, and see the Stars around it. - Isaac Watts, A.D. 1726
For example, during the early autumn, the Sun is at the autumnal equinox and the lengths of daylight and nighttime are equal. At this time, the point in the sky of the vernal equinox is rising in the evening sky as the Sun sets. Thus, the point of the vernal equinox reaches the middle of the sky at astronomical midnight.
At midnight on this date, the zodiac constellations Pisces, which hosts the vernal equinox, is at its highest place in the night sky. Nearby constellations including Aquarius are also in the sky. However, Pisces and Aquarius are formed of very faint stars, and are thus hard to see from light-drenched urban locations and can only be seen from dark rural skies.
However, brighter stars such as the Great Square of Pegasus and the first magnitude star Fomalhaut can be seen from just about everywhere, and can help mark the opposite point of the Sun on the autumnal equinox.
One thing to keep in mind is that, under our global system of standard time, astronomical midnight is not the same as midnight on the clock. During daylight savings time, true astronomical midnight can be as late as 1:30 AM, depending on where one is located within a time zone. However, if you observe anytime around 1:00 AM, you should get the general idea.
Coming in future Classical Astronomy Updates:
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Into the fall, the planet Venus will become prominent in the evening sky.
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We hope to explain about light pollution and how street lighting can spoil the quality of the night sky.
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In 2009, we will celebrate the Quadricentennials of Galileo and Kepler.
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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