Changes in Latitude

Most of us probably have at least a rough idea of how Longitude and Latitude work.  Longitude measures how far east or west of (a line drawn from pole to pole through) London a place is, and Latitude measures how far north or south of the Equator it is. They’re measured in Degrees; up to 180° E or W, and up to 90° N or S.

Our Time Zones are based on Longitude, with adjustments for political boundaries, economic relationships, etc.  For instance, New York and Detroit are in the same Time Zone even though they’re quite a few Degrees apart, and the westernmost part of Michigan that’s in the Eastern Time Zone is only a few miles from what should be the center of the Central Time Zone.

It gets more complicated when you start projecting lines of Longitude and Latitude into the Sky.  Adjustment here aren’t made for the convenience of politics or commerce, but for the ease of astronomy.  The Equator is equidistant from the Poles, but the Polar Axis is tilted relative to our orbit around the Sun.  That’s what gives us our Seasons, as our half of the Planet is tilted toward or away from the Sun.  For astronomers, it’s the plane of our orbit around the Sun that’s far more important than the Equator.

(Now, I’m not an astronomer, so I’ll have to tell you how I understand it to be, which may be a bit different than how an astronomer would describe it.)  Projected into the Sky, the plane of our orbit around the Sun is called the “Ecliptic.”  The Moon’s Nodes, for instance, are the places where the Moon crosses the Ecliptic, North when it’s crossing from below to above and South when it’s crossing from above to below.  Of course that’s “above” and “below” from the Northern Perspective; it’s the other way around when seen from Australia or Argentina or Botswana.

The distance from a planet in the Sky to the Ecliptic is called its “Declination.”  It’s like Latitude, but not quite, because it’s relative to the Ecliptic rather than the Equator, and the relationship between Latitude and Declination changes with the Seasons.  But in a very loose, averagey kind of way, you can think of Declination as a substitute for Latitude, so a planet at 49° N Declination is roughly overhead in Paris, and one at 34° S Declination is roughly overhead in Sydney.

Astrological Longitude gets tricky because of what astrologers call the “Precession of the Equinoxes,” which means that the “Fixed” Stars aren’t really Fixed, when seen from Earth.  Of course, as usual, it’s us that’s moving, not them.  Well, of course they’re moving too, but they’re so far away we can’t really detect it.  But the point is that, relative to our Longitude, the Stars are slowly moving, about 0.84 arcseconds a year.  In 26,000 years or so, they’ll be back to where they are now.

Divide that 26,000 years by 12 (astrologers divide by 12 quite a lot – it’s a Sacred Geometry sort of thing), and you get our roughly-two-millennia-long “Ages,” as in the “Age of Pisces” (which we’re leaving) and the “Age of Aquarius,” which we’re entering.  From our Perspective, its the Equinox that’s moving relative to the Stars.  So when the North Pole is leaning toward the Sun at max (the Northern Spring), the Stars will have moved a little  from where they were last year at this time.

There are actually two different kinds of astrology, one based on the position of the Stars, and one based on the position of the Equinox.  (Of course there are many more, but we only need to consider two here.)  We use “Tropical” astrology, in which 0° Aries is when the North Pole leans toward the Sun at max (which puts the Sun overhead at 23:27° N Latitude, on the “Tropic of Cancer,” hence “Tropical” astrology).  In Sidereal astrology, 0° Aries is when the Sun enters the Constellation Aries (the Constellations move with the Stars).  A couple thousand years ago, they were the same.

When astrologers say that two planets are Conjunct, they aren’t really one behind the other – that’s called an “Occultation,” meaning one really is Hidden or Occulted by the other – “Occult” just means Hidden.  A Conjunction just means that they are on the same astrological Longitude in the Sky, even if their Declinations are separated by half the visible sky.

A reader has asked…

“Maybe I’m missin’ the boat, but if da Moon is currently at 9 degrees of Capricorn, then how is it OOB?  I’ve got my Moon in Cap at 23 deg plus, which is defo OOBs.”

Nine (or any) Degrees of Capricorn (or any Sign) is the astrological Longitude (East/West).  The Moon goes Out of Bounds when it exceeds 23:27 Degrees of Declination (North/South).  A Full Moon at 9 Capricorn would Oppose the Sun around the end of June.  The Moon goes from max North to max South every 28 days or so.  How far max North or South is what varies on the 20-or-so-year Cycle – for about ten years the Moon never goes OOB (beyond 23:27° N or S), then for the following decade or so the Moon goes OOB for a day or two every two weeks, alternating between N and S.

Out of Bounds is defined by the Tropics of Cancer and Capricorn – 27:23° N and S.  The Sun never goes beyond those Latitudes or Declinations, barring an asteroid collision that’s big enough to alter the Earth’s tilt – in which case we wouldn’t be in a position to care.  The Sun is always on the Ecliptic, so for a Solar or Lunar Eclipse to occur, the Moon also needs to be near the Ecliptic, which the Moon crosses every two weeks.

An Eclipse is an Occultation, also sometimes called a Parallel Conjunction when planets other than the Sun and Moon are involved.  Latitudes, and Declinations by extension, are sometimes called “Parallels,” because lines of Latitude are indeed parallel to one another.  Lines of Longitude on the other hand Converge at the Poles.  Hence the name Parallel Conjunction for Occultations, or Contra-Parallel Conjunction when the two Conjoining planets are in the same Degree of Declination, but one is North (often written as “+”) and the other South (often written as “-“) of the Ecliptic.

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