DSC07155Well, we did it.  We successfully had another Autumnal Equinox, changed seasons and entered fall.  And at least as of sunset on the 23rd, the world hasn’t ended, despite predictions to the contrary!  It’s still above 80 deg-F outside, and I’m still mowing my lawn – but astronomically, the nights are now longer than the days, and it’s not summer anymore.  The equinox isn’t just the day that night and day swap places (with regard to which is longest, I mean), it’s an actual moment.  A precise moment when the Sun crosses the equator (both the Earth’s equator, and the Celestial equator, at the same time.  Sounds like a neat trick, except that one is defined by the other, so it’s not that hard to do).  So on Friday, at 20:02 UTC (4:02pm Eastern Daylight Time), the Sun entered the southern hemisphere, bringing spring to those south of the equator, and autumn to me.  I barely felt it.

In the sky, we still have the Summer Triangle high overhead – Jupiter is getting low in the west after sunset, and even Saturn has passed the meridian and is in the western half of the sky.  The rest of the naked-eye planets are hanging around in the eastern sky at dawn, on the other side of the Sun.

Soon, we’ll be seeing Fomalhaut – the “Lonely One”, the “Solitary One”, the “Autumn Star” – brightest in a dark area of sky known popularly as, “that dark part of the southern autumn sky where all you can see is Fomalhaut”.  Looking around though, there’s a neat trend in these lesser known constellations – it’s pretty wet out there, and this relatively dark region is sometimes called “The Sea”.  As we journey through this part of the sky, I’m presenting a lot more of the artistic representations of the constellations than I usually do (I’m usually focused on the stars).  In this case, the art and the oceanic correlation is just a bit more colorful.

The Sea - Late Septmeber South

The western side of “The Sea”.  Looking south in late September, about 9:30pm (from about 38 deg north).  Screenshot via Stellarium.

Our old friend Capricornus, which I discussed some weeks ago, kicks off the strange cavalcade of sea creatures.  Next to the sea goat, Aquarius, the next in the Zodiac line (more on him later) is pouring water down on top of Piscis Austrinus, the “southern fish”, not to be confused with Pisces, proper.  Fomalhaut (whose name derives from “mouth of fish” in Arabic) is the brightest star in Piscis Austrinis, and sits low in the south – all alone – through autumn.

On the other side of Aquarius is Cetus, the “whale”.  At least, we call it a whale – it is often depicted, in Capricornus-like fashion, as having the head of some other animal, and the tail of a fish.  Cetus has been traditionally referred to as the sea monster killed by Perseus in Greek mythology, and has also been referred to as a dragon-fish.  In any case, his origins are not just “whale”, as these horrific depictions, dating from 1690 and 1825, should clearly demonstrate.  Cetus is, by the way, close enough to the ecliptic plane that planets and the Moon sometimes wander into it.  Like Ophiuchus, it’s occasionally a non-Zodiac hangout for other celestial bodies.

744px-Cetus_Hevelius

Cetus, as drawn by Johannes Hevelius in his 1690 catalog, Uranographia. Drawing is a mirror image of the sky, as it represented a celestial globe viewed from outside, looking towards Earth. Public Domain in the USA – work is older than the author’s life plus 100 years.

Sidney_Hall_-_Urania's_Mirror_-_Psalterium_Georgii,_Fluvius_Eridanus,_Cetus,_Officina_Sculptoris,_Fornax_Chemica,_and_Machina_Electrica

Cetus and neighboring constellations, as presented in “Urania’s Mirror”, a collection of cards by Jehosophat Aspin, 1825 London. Public Domain in the USA – work is older than author’s life plus 100 years.

Pisces, the “fish”, another Zodiac constellation, rises above Cetus’s back.  Depicted as two fish tied together, they correlate to Aphrodite and Eros in Greek mythology.  In order to escape the monster Typhon, these two transformed themselves into fish, but kept a cord tied between them to avoid being separated.  If you recall, Pan/Bacchus did the same thing, for the same reason, to form Capricornus, but only went in halfway so he added a fish tail to his saytr/goat form to create the weird sea-goat.  The moral here:  Typhon was a seriously scary dude.

The Sea - Late Septmeber East

The eastern side of “The Sea”.  Facing east at the same time (about 9:30pm) as the picture above.  Screenshot via Stellarium.

Wrapping around to the east and south of Cetus is Eridanus, the “river”.  This river has represented many REAL terrestrial rivers, including various Babylonian waterways, the Nile, the Po River in Italy… to me it represents serious lack of imagination.  Seriously, Eridanus is matched only by (possibly) Hydra (the “serpent”) and Draco (the “dragon”) for arbitrary star arrangements.  At least the other two have heads of some sort – but these constellations are literally the meandering curves made up of stars not otherwise accounted for.  Eridanus looks as if the ancients picked out all the easily recognizable shapes they could see, then connected the stars left over from Orion to Cetus, and then south to well below the equator (and my visible horizon), and called it, creatively, a “river”.   You can see it meandering under Cetus’s feet – yes, “whale” feet – in the illustrations above, and it winds east all the way to Orion’s knees.  C’mon Babylonians, and/or Ptolemy.  I expect better!

The Sea - Late Septmeber Up

Again at the same time, little Delphinus is almost straight up, near Altair in the Summer Triangle.  Note Aquarius and Capricornus here for reference, as well.

Finally, not really a part of the sea grouping, but set apart, leaping up over Aquarius’s head near Aquila and the Summer Triangle, is little Delphinus, the “dolphin”.  It’s somehow fitting that he’s leaping above the rest.

So there you have it – a quick introduction to an often overlooked corner of the sky.  An enormous swath of strange sea-dwellers so unremarkable that Fomalhaut still stands out as the lonely star of autumn.

I can’t leave, though, without pointing out one more thing.  you may have noticed in the attached images – but here in the midst of all these ancient godly fish and scary sea beasts, we have a splash of modernity:  Microscopium (the “microscope”), Fornax (“the furnace” – or “chemical furnace” in the 1825 depiction of Cetus), Sculptor (“the sculpture” – 18th century), and just south of Sagittarius, Telescopium (the “telescope”).  In addition, we see in the 1825 drawing constellations that are now-extinct, and unrecognized – Psalterium Georgii (“George’s Harp” to honor Britain’s King George III), and the Machina Electrica (or “electric machine”) that looks nicely early-19th century steampunk!  Our stars, and our interpretation of them, just keep evolving with us!

Get Out There
Troy
flying-squirrel.org

3 thoughts on “Beyond the Equinox, Beyond the Sea (Astronomy: Week of 9/24/17)

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