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.
Then spake Joshua to the Lord in the day when the Lord delivered up the Amorites before the children of Israel, and he said in the sight of Israel, Sun, stand thou still upon Gibeon; and thou, Moon, in the valley of Ajalon. And the sun stood still, and the moon stayed,
until the people had avenged themselves upon their enemies. Is not this written in the book of Jasher? So the sun stood still in
the midst of heaven, and hasted not to go down about a whole day. -- Joshua 10:12-13 IN THIS
UPDATE Lunar Standstill Hi Friends, The
previous newsletter was intended to be the last of 2024, but then something came to my attention which I wanted to share with you all. This will be a rather deep topic, so if you're new to Classical Astronomy, the explanation might be somewhat abstruse. ("Absruse" is a very abstruse word, don't you think?) But the takeaway is something everyone should be able to see and appreciate so please bear with me! Triumph of Western Civilization My heart was warmed to see the unveiling of the restored Notre Dame Cathedral in Paris. Though this is a Roman Catholic church, one need not be Catholic to appreciate that this is one of the monumental works of western civilization. Like
many, I was disheartened at the fire that nearly destroyed this 850 year old edifice in 2019. This sad event signified the decay and decline of western civilization, which is so evident in so many ways. But the restoration signifies the indominable spirit that helped give rise to our civilization in the first place. While western
civilization has its roots in ancient societies, it came into full flower with Christianity, in which the currents of Greece and Rome flowed together with Judaism to create a civilization that touches every human today, believers and unbelievers alike. Christianity holds that each human being has value, everyone being made in the image of God
(Imago Dei). This was an historical innovation. Roman pagan culture held little value for human life. Only the wealthy received health care, and unwanted children were abandoned to the wolves. The concept of hospitals and orphanages arose in obedience to Jesus' command to care for the sick and children in need. Yet there are likely few nations or cultures in the world today where hospitals and child care are not available. Cathedrals such as Notre Dame were created as acts of Christian worship. While Scripture teaches that the "Lord of heaven and earth dwelleth not in temples made with hands" (Acts 17:24), we can still admire the medieval heart of worship. Cathedral construction took centuries to complete. Generations of craftsmen toiled devotedly at their task, never seeing the end
product in their lifetimes. In the process of erecting such monuments of faith, the modern scientific principles of architecture were sorted out through trial and error over long spans of time. Similarly, the original raison d'etre for modern science is
also founded in Christian culture, based on the premise that the universe is the product of a rational Creator and therefore established according to rational principles. Early modern Christian scientists believed they were "thinking God's thoughts after Him" in their scientific investigations. While the craftsmen of today's Notre Dame restoration might have been less motivated by faith and devotion than their ancestors, they completed the effort in a mere half decade by relying upon
the fruits of centuries of scientific advancement, built upon that Christian foundation. Of course western civilization has been imperfect down through history. Every day the critics remind us of its sins and failures. The same could be said of every other civilization, composed as they all are of imperfect human sinners. But
considering the cost/benefit ratio, an argument can be made that western civilization is less imperfect than all other world civilizations. The original construction and current restoration of Notre Dame symbolizes the best of western civilization. But we
can all appreciate the worst, such as the dangers of a reckless modern science decoupled from its Christian moral foundation. Modern secular scientific research is directed more by whether something can be done rather than whether it should be done. Modern science has thus learned how to inflict mass
death and Frankenstein manipulation upon those same image bearers along with health and bounty. While the restoration of Notre Dame might be a triumph of western civilization, it might also be a swan song. It remains to be seen over the short term. If you want to be inspired watch this video of Amazing Grace sung at the Notre Dame
dedication. Consider the long history of this church: built during the era of the Crusades and the Black Death; the Cathedral of Louis XIV, the Sun King; home of the fictional Hunchback; endured the French Revolution and survived two world wars; the church of French monarchs who fought the English kings for centuries, including the Hundred
Years War featuring the likes of Henry V and Joan of Arc. Notre Dame Cathedral stood through all that only to be pointlessly burned in an contractor accident (or possibly a covert act of sabotage), only to rise like a phoenix from the
ashes. Also consider all the cultural currents of Christian reconciliation and the history of western civilization that come together in a Venezuelan conductor accompanying a black South African opera soprano singing an English Protestant hymn in this French Catholic cathedral. This makes me very proud to be a Christian and an heir to
the legacy of western civilization. It is imperative that our generation resist the 21st century barbarians at our gates and be brave and bold to protect and defend our western tradition here within our lifetimes, to pass this legacy onto posterity, that our culture would not pass away into the dark night. But the above notwithstanding,
whatever transpires in this world, a core message of the Gospel is that we do not place our hope in the things of this world but in the return of Jesus, whose Incarnation we celebrate here in the Christmas season. He which testifieth these things saith, Surely I come quickly. Amen. Even so, come, Lord Jesus. The grace of our Lord Jesus Christ be
with you all. Amen. -- Revelation 22:20-21 For more information about topics from Classical Astronomy discussed in this newsletter, please check out a homeschool astronomy curriculum (but popular with adult readers too!) Visit our archive of previous editions of the Classical Astronomy Update newsletters, going back to 2007. ***** Lunar Standstill After the last newsletter, I got an email from Pat in Ohio with the Stillwell Stargazers pointing out the current Lunar Maximum Standstill. I never heard this term before, though I'm familiar with the concept. And I was not paying attention and did not realize that we are currently in the midst of the maximum of an 18.6 year lunar cycle. So many thanks to Pat for bringing this to my attention! Long story short, in the current season, there will be certain nights when the Moon will reach its maximum northern altitude in the sky over the span of years between 2006 and 2043. This means that the Moon will be at its highest overhead, something everyone can see and appreciate. In the southern USA, the Moon will pass directly overhead, especially as seen from Central Florida and South
Texas. Since this only happens every 18 years or so, there are only a few opportunities in a human lifetime to witness this. So don't miss out! So What's Happening? We've all seen the standard textbook view of the solar
system, with the planets circling the Sun in the planes of their orbits. We've also all seen the textbook views showing the Earth on its axis tilted 23 1/2 degrees toward the plane of its orbit, with the usual vague assurance that this is somehow the cause of the seasonal variations between summer and winter. The textbooks usually fail to explain that the
plane of the Earth's orbit is called the plane of the ecliptic, and that the ecliptic is seen in the sky as a circle defining the apparent path of the Sun through the constellations, as explained in our Signs & Seasons astronomy curriculum.
The ecliptic circle is tilted compared to the rest of the sky so that its northernmost point is in the constellation Gemini, above the famous constellation Orion the Hunter and its southernmost point is in Sagittarius, opposite in the sky from Gemini. The Sun is aligned with that northernmost point on the day of the summer solstice,
in which it is highest overhead at noon as seen from places in the northern hemisphere, casting the shortest noon shadows of the year. Conversely, the Sun is aligned with the southernmost point on the winter solstice, in which it is lowest in the southern sky at noon as seen from places in the northern hemisphere, casting the longest noon shadows of the year. So anyway, the Moon twirls through these same constellations in a similar cycle as it circles the Earth each month. The Moon thus has a type of monthly "solstices" of its own. The Moon "rides high" each month when it passes through Gemini and "runs low" when it passes through Sagittarius, no matter the phase. As I've recently learned, this is lately called lunar standstill since the Moon "stands" at its northern and southern extremes before
changing direction, just the Sun on the solstices. ("Solstice" in Latin means "the Sun stands.") Every 18.6 years there are extreme lunar standstills in which the Moon can be 10 lunar diameters higher in the sky than a regular northern extreme and 10 lunar diameters lower than a normal southern extreme. This extreme condition is called major lunar
standstill. This extra boost is the result of the lunar nodal cycle, one of the many cycles of the Moon. The Moon circles the Earth in its own orbital plane which is similar to but slightly different from the plane of the ecliptic. The Moon's orbit is inclined 5.2 degrees to the Earth's orbit. The places where the Moon crosses the ecliptic are
the nodes. There is an ascending node where the Moon crosses the ecliptic heading north and a descending node where the Moon crosses heading south. The ascending node is designated by the Greek letter omega as shown in the pic below. The Moon only crosses the ecliptic when it passes the nodes. This happens each month, whatever the phase. Each year there are months when the New Moon crosses a node, in which case it is aligned with the Sun,
producing a solar eclipse. This is the reason for the name "ecliptic" since an eclipse can only happen in such months. In other months, the node does not align with the Sun and no eclipse occurs. In certain months the New Moon occurs a quarter of the way around its orbit from the ascending node, the maximum distance, and the Moon can be
seen 5.2 degrees to the north of the Sun along the ecliptic. Since the Moon appears only a half-degree in angular diameter, the New Moon is more than 1o lunar diameters above the Sun. As shown in the node diagram above, the Moon's nodes are constantly slipping to the west along the ecliptic, moving in reverse, opposite of the usual easterly direction of the Moon's regular orbital motion. This is the
Regression of the Nodes, the result of a gravitational tug-of-war between the Earth and the Sun acting upon the Moon. Due to nodal regression, the lunar orbital plane rotates in an 18.6 year cycle so that the nodes move backwards along the ecliptic. In the current season, the Moon's ascending node has been in the constellation Pisces, approaching the
point of the vernal equinox on the ecliptic. This is where the Sun is aligned each year around the first day of spring, March 21. The vernal equinox is defined as the origin, 0 degrees, in the ecliptic coordinate system, which will be explained in Measuring the Heavens, the upcoming sequel to Signs &
Seasons, currently in production. Back on April 8, 2024 the ascending node was at 15.3 degrees on the ecliptic and since the Sun was nearby, many of us experienced the Eclipse Over Cleveland on that date. The node will regress to the zero point of the vernal equinox on January 10, 2025 and will slip further backwards to 352.8 degrees by June 11, 2025. As a result, when the ascending node is close to the vernal equinox, the Moon's orbit is the steepest possible angle. This gives the Moon that extra 5 degree boost to the north when it passes the northernmost point of the summer solstice, above Orion. So you end up with the Moon being 10 lunar
diameters further to the north than the usual northerly point along the ecliptic. This is major lunar standstill, also known as the Moon's maximum northern declination. Clear as mud, right? Like I said above, "abstruse." Whether or not that technical explanation makes any sense, the main takeway is that we have a rare opportunity to see the Moon higher in the sky overhead than otherwise possible over the next several months. On the night of Sunday, December 15 (around 1:00 AM on Monday the 16th) look for the Full Moon as it crosses the meridian, hanging high above the south. Look at your shadow and it should be mimimal. If you live in Florida around Tampa or Orlando, or in Texas south of Houston or San Antonio, you can see the Moon directly overhead so that your shadow will
disappear! If that hour is too late for you, you'll have another chance on the night of January 11, 2025 when the not-quite-full waxing gibbous Moon aligns high above the solstice point. Look for that sometime around 11:00 PM. Also take a peek at any hour of the evenings before these dates (December 14 and January 10) to see the Moon aligned with the bright planet Jupiter in its monthly conjunction. (See the previous newsletter for more information about Jupiter.) If neither of those nights work out there'll be other
opportunities in February and March before Orion sky rolls west into the sunset for the season. Hopefully we'll report about those in a future newsletter. This topic came up when Pat from Ohio mentioned observing a very low hanging waxing crescent Moon back in the fall and noticed that this was due to the descending node being aligned closely with the
fall sunset. This observation also follows from the current node configuration since the descending node is similarly aligned with the point of the autumnal equinox -- the opposite node lined up with the opposite equinox. This has the effect of lowering the waxing crescent Moons of fall below their normal positions, only about 10 degrees above the horizon in twilight. I noticed the same thing on the evening of September 5, 2024 but didn't make the connection. So thanks
again Pat! Looking at the data, I see that this pattern will become more pronounced every fall until reaching a maximum in 2028 when the descending node will be 90 degrees away from the autumnal equinox. In that season the same crescent Moons will be only 4 degrees above the horizon. This will be hard to see and only visible over water or a very flat,
treeless horizon, such as the cornfields of Illinois. In 2025 the current major lunar standstill configuration also results in a lunar maximum southern declination when the Moon is at its minimum altitude above the horizon while transiting in the south. So in the late spring on June 11, 2025, just before the longest day, you can expect to see the Full
Moon in Sagittarius about 10 degrees lower than its normal spot, a mere 16 degrees above the horizon here in Cleveland, lost in the treeline unless you're somewhere in Ohio farmland. This is the way the Full Moon would appear in subarctic latitudes, so this will be a rare sight for people in our zone. I'll try to also remember to put that into an upcoming newsletter. Once again, from our family to yours, we wish you all a very Merry Christmas and prosperous and healthy New Year! Till 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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