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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
- Look for Signs & Seasons!
- Mechanical Universe now Available Online
- Astronomical Topics
- Easter and Passover - Similarities and Differences
- Dance of the Planets
- Saturn in Leo in the Spring of 2008
Who hath divided a watercourse for the overflowing of waters, or a way for the
lightning of thunder; To cause it to rain on the earth, where no man is; on
the wilderness, wherein there is no man; To satisfy the desolate and
waste ground; and to cause the bud of the tender herb to
spring forth? Hath the rain a father? or who hath
begotten the drops of dew? - Job 38:25-28
Welcome to the Classical Astronomy Update!
Hello Friends,
Sorry it's been so long since the last Update. We try to write this newsletter at least twice a month, but things have been very busy lately with my day job. Many thanks to everyone who wrote nice things in response to our Easter article last month. We really appreciate your kind support in taking the time to communicate.
Don't forget about the Classical Astronomy Yahoo Group. Even though there are now over 100 members, very few conversation threads get started over there. We sure would like it if more people would ask questions or otherwise start topics in that group. Thanks for your interest.
Announcements
Look for Signs & Seasons!
We're happy to report that our Signs & Seasons curriculum has been picked up by a number of homeschool booksellers for 2008. If you attend any homeschool conventions this year, please be sure to look for this astronomy curriculum. Check out our Distributors page for a list of sellers. Also look for our upcoming ads in Homeschooling Today, Homeschool Enrichment, The Old Schoolhouse, WORLD, and Creation Illustrated magazines.
If your family likes the things we discuss here in the Update, you really should check out Signs & Seasons. This curriculum is designed to help homescholars (and their parents!) to learn to observe and understand the motions of the Sun, Moon, and planets. This isn't just another generic modern astronomy "tour of the solar system" textbook. Why learn "astro-facts" about the planets when you can learn to actually find the planets in the night sky? Check out our Signs & Seasons page for a Table of Contents, PDF sample, and an animation about this curriculum.
People always tell me, "but we're not studying astronomy this year." But visual astronomy isn't a subject like math or history just sitting there waiting to be studied. Each year brings unique astronomy events, some of which may not occur again in your lifetime. Each year that you don't learn the sky is another year of celestial events that you and your family will miss forever.
Here's what the homeschool magazines have said about Signs & Seasons:
Signs & Seasons is the clearest, most concise book on astronomny that I've ever had the pleasure of reading. - Homeschool Enrichment
Our kids are getting the best possible astronomy class with Signs & Seasons. - The Old Schoolhouse
Include this delightful book in your study of God's creation. - Homeschooling Today
For more, check out our Endorsements page.
Special Pre-Convention Season Offer!
Order Signs & Seasons now, direct from us, and receive free shipping! Wow, what a great deal! This offer expires May 1, 2008.
Make this the year your family studies astronomy!
Also, standby for information about our upcoming Signs & Seasons Field Journal and Test Manual. Trust me, you will not want your homeschool to be without this!
Mechanical Universe Now Available Online
We are very pleased to report that The Mechanical Universe, the outstanding PBS series on physics, is now available for viewing online. This excellent series came out in the mid-80s when I was a physics undergrad student. It contains some very excellent animations that give a crystal-clear understanding of real world physics. In fact, this series was a partial inspiration for my own efforts in using visual media for teaching science.
Check it out at the series web site. Click the "VoD" icons to view each episode of the series as streaming video. Here's a tip -- skip the first episode, which includes the usual PBS secular humanist, Sagan-style boilerplate. After that, the series settles into real-world, real-time science that forms the basis of our high-tech culture. This series would be a great benefit to any homeschoolers using Apologia or Saxon physics, or seeking careers in science or engineering.
Astronomical Topics
Easter and Passover - Similarities and Differences
As we saw in the last Update, the Christian observance of Easter was originally based on the Jewish Passover, and developed its own cultural distinctives over the centuries. This current month provides evidence of this divergence. April, 2008 roughly corresponds with the month of Nisan, 5768 in the Jewish calendar. Being a lunar calendar, the month Nisan begins at the first sighting of the waxing crescent Moon after its invisible conjunction with the Sun. Passover (Pesach) lands on 14 Nisan, which is the Full Moon of this month, 14 days afterwards.
However, as we saw in the last Update, Easter (a.k.a. Pascha) landed on a very early date in late March. Someone asked me recently which is the "right" time to celebrate Pesach/Pascha. Unfortunately, the LORD does not give clear astronomical guidelines in Scripture, and if He did, it would settle the differences of opinion on the matter. Here is what the Torah has to say:
Thou shalt keep the feast of unleavened bread: (thou shalt eat unleavened bread seven days, as I commanded thee, in the time appointed of the month Abib; for in it thou camest out from Egypt: and none shall appear before me empty:) - Exodus 23:15
The feast of unleavened bread shalt thou keep. Seven days thou shalt eat unleavened bread, as I commanded thee, in the time of the month Abib: for in the month Abib thou camest out from Egypt. - Exodus 34:18
Observe the month of Abib, and keep the passover unto the LORD thy God: for in the month of Abib the LORD thy God brought thee forth out of Egypt by night. - Deuteronomy 16:1
My concordance identifies the month of Abib with "the first month of the year," indicating springtime since the word means "sprouting" or "budding." If only Scripture would nail down exactly how that should be determined! The passage of the seasons is linked to the annual cycle of the Sun. However, the Hebrew feasts are reckoned by the monthly cycles of the Moon.
The timing of Easter is related to the Full Moon and also the Sun's vernal equinox. Meanwhile, the modern Hebrew calendar is based on the 19 year cycle of the Sun and Moon, which keeps the lunar months on track with the seasons. This means that every so often, you need to throw in an extra month. This happened here in 2008, when Easter landed in the Jewish month of "second Adar," which only happens every few years.
Arguably, Easter, 2008 was closer to the "first month" than Passover, 5768. However, the Hebrew calendar, even with its extra intercalary months, is necessary to make tables and to keep long term lunar timekeeping in step with the seasons. In comparison, a strict twelve-month lunar calendar is maintained in Islam. But since it is only 354 days long, the Islamic calendar drifts along through the seasons over a span of decades. Perhaps this isn't an issue in the arid lands of Arabia, but it would be a big matter for Pesach/Pascha, which must fall within the time of "sprouting" or "budding."
In my opinion, if the LORD intended there to be a "right" time for finding the time of Passover, He would either have given Moses more explicit instructions, or else he would have made the Sun and Moon to agree more closely. In any case, the LORD has made provision in these astronomical discrepancies, as they have given astronomers an opportunity to study the sky in detail, and a great many useful things have been learned in the process.
The Church Calendar and the Jewish Calendar
As we've seen in other Updates, the traditional Christian ecclessiastical calendar does include a cycle of "moveable feasts" that correspond to certain Hebrew feasts. But rather than commemorate events in the history of Israel, the church calendar remembers events in the New Testament.
Easter is preceded by Lent, a 40-day period of reflection and repentance beginning on Ash Wednesday, and corresponds with Jesus' 40 days in the desert, as recorded in Matthew 4:2, Mark 1:13, and Luke 4:2. But Easter itself is not simply a one-day feast. Easter Sunday is traditionally the beginning of a 40-day period of "Eastertide," which commemorates the 40 days that Jesus appeared to His disciples after the Resurrection, as recorded in Acts 1:3:
To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:
Eastertide ends on Ascension Thursday, 40 days after Easter Sunday, which commemorates when the LORD ascended into heaven. The Easter cycle finally ends on Pentecost, which is 50 days after Easter Sunday. Pentecost is remembered as the "birthday of the church," when the Holy Spirit came down upon the Apostles and moved Peter to preach, leading 3000 souls to Christ, as we read in Acts 2. In this way, the traditional church calendar devotes nearly three months to the passion and glorification of Christ.
The feast of Pentecost corresponds to the Hebrew Shavuot, or the Feast of Weeks, as instructed in Leviticus and Deuteronomy:
And ye shall count unto you from the morrow after the sabbath, from the day that ye brought the sheaf of the wave offering; seven sabbaths shall be complete: Even unto the morrow after the seventh sabbath shall ye number fifty days; and ye shall offer a new meat offering unto the LORD. - Leviticus 23, 15-16
Seven weeks shalt thou number unto thee: begin to number the seven weeks from such time as thou beginnest to put the sickle to the corn. And thou shalt keep the feast of weeks unto the LORD thy God with a tribute of a freewill offering of thine hand, which thou shalt give unto the LORD thy God, according as the LORD thy God hath blessed thee: - Deuteronomy 16:9-10
Shavuot commemorates the day when Moses brought the Torah down to Israel from Mount Sinai, representing the Old Covenant. The Christian feast of Pentecost remembers the day the Holy Spirit was poured out, signifying the New Covenant. Israel became a nation 50 days after the Passover lamb was killed, and the church was established 50 days after the paschal sacrifice of Jesus.
Ascension Thursday is on May 1, 2008. Pentecost (or Whit Sunday) is on May 11 this year. Though most evangelicals do not follow the ecclessiastical calendar, it's nevertheless interesting to understand what it is meant to represent.
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Dance of the Planets
Saturn in Leo in the Spring of 2008
It's once again that time of year when "the Lion is higher than Orion"! After proclaiming the glory of God through the winter months, the awesome constellation Orion is once again sinking toward the sunset as the days of spring grow warmer and longer. In this month, the constellation Leo is high in the evening sky after sunset.
Unlike a lot of constellations, Leo actually looks like the object it is supposed to represent. Its trapezoidal shape looks like a big cat in mid-jump, and a faint "sickle" of stars is reasonably recognizable as a head.
 In the current season, Leo is joined by the planet Saturn, which is the brighter "star" nearby the star Regulus in Leo. If you've been observing Leo and Saturn throughout this winter, you have had an excellent opportunity to observe the "retrograde motion" of this planet.
 In the weeks before the Earth "passed" Saturn back in February, the Earth's motion has caused a change in the line of sight between Saturn and the more distant background stars, causing the ringed planet to appear to move backwards.
Consequently, Saturn appears to be moving west and approaching Regulus. Since Saturn's position on the night of the lunar eclipse in February, Saturn has moved quite a noticable distance to the west. These two bodies will make their closest approach at its "station" on May 3, when Saturn will be only a couple Moon diameters away from Regulus. After that time, Saturn will resume its regular eastward motion and will draw away from Regulus.
The waxing gibbous Moon will pass near Regulus and Saturn on the evening of Tuesday, May 15, 2008. Though this will be visible from North America, these bodies will appear very close to the Moon as seen from the meridians of Europe and Africa. The meridian of Jerusalem will be especially favored for this conjunction, and the Moon will appear very close to Regulus. Observers to the south in Madagascar will be able to see an occultation of Regulus by the Moon, in which the Moon will pass in front of this star, covering it from view for a time. Wherever you are, this lunar conjunction should be a pretty sight for everyone in the world.
Coming in future Classical Astronomy Updates
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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