Wednesday, October 21, 2020

Mars over Cetus!


image: Wikimedia commons (link). 

If you are able to make a habit of going out under the night sky on a regular basis, then you probably already know that the planet Mars is absolutely glaring in its brightness in the heavens right now -- perhaps because the planet is closer to us than usual (see discussion of the debate over the mechanics and arrangement of our solar system stretching back to the days of Tycho Brahe and his erstwhile assistant Johannes Kepler, here).

The planet Mars is absolutely unmistakable in the sky, rising in the east in the hours after sunset and making its transit (crossing the highest point of its arc on its journey from east to west, which it crosses when transitioning the celestial meridian line indicating due south, for observers in the northern hemisphere, and due north for observers in the southern) at about midnight during the next few days.

Below is a screenshot of the sky from the free and open-source planetarium app Stellarium, showing the sky at midnight (from the perspective of an observer in the northern hemisphere, at about 35 N latitude) on October 22 to 23 (midnight on October 22nd, just as the date rolls over to October 23rd). Notice Mars near its highest point in its east-to-west arc, crossing just above the line of due south:


Mars happens to be situated in the zodiac constellation of Pisces right now, which is a faint constellation but one that flanks the two "lower edges" of the Great Square of Pegasus, which is a very bright and easily distinguishable asterism. You should be able to identify the Great Square in the night sky above Mars (and just to the west of the Red Planet) even without ideal darkness and viewing conditions.

The Great Square is a very easy landmark to find in the sky, but the Red Planet's current location also gives star-gazers a tremendous opportunity to locate the much more difficult and obscure constellation of Cetus the Whale (or Sea-Monster). 

The location of Mars in the night sky over the next two weeks will provide a fantastic "handrail" to help you find the constellation Cetus, if you have the opportunity to get out under the stars in a reasonably dark location free of light pollution. Mars is almost directly above Cetus, and in fact almost directly above the "eye" of Cetus, as shown in the close-up screenshot below. 

Cetus is a constellation that is fairly low in the sky (for observers in the northern hemisphere), because fairly far south in the celestial sphere, and so the best opportunity to see Cetus is when the constellation is highest on its arcing path from east to west. Since Mars is directly above Cetus right now, that means that the best time to try to locate Cetus is when Mars is also reaching its apex (or transit) from east to west, which takes place around midnight over the next few days. 

Below is a close-up of the same star chart shown above, but this time zoomed-in on Cetus and Mars, with the landmark of the Great Square and the outline of Cetus indicated with bold lines:


In the above star-chart, I have indicated the position of the planet Mars (with a red arrow pointing towards Mars), and I have outlined the constellation Cetus (which is a faint constellation and generally somewhat difficult to find in the night sky). I have taken the liberty of circling the "eye" of the constellation Cetus, which as you can see is almost directly "below" the planet Mars right now (for observers in the northern hemisphere, and "above" for those in the southern).

This alignment makes the next few weeks a wonderful opportunity for finding Cetus! I must admit that I myself usually have trouble finding Cetus, because it is so faint and generally so low to the southern horizon from my latitude, but the present location of Mars makes it relatively easy to find and trace out.

The biggest problem for star-gazers right now is the fact that the Moon is now beginning to wax larger and larger each night, on its way to a Full Moon on the significant date of October 31. The increasing brightness of the Moon, and its nightly motion from the west towards the east, will make it more and more difficult to see Cetus until we get past the Full Moon. 

However, after Full Moon, as the Moon continues to rise later and later each night -- and as the Moon begins to wane towards a crescent again -- we will get another tremendous opportunity to find Cetus underneath Mars.

Below is another star-chart screenshot from Stellarium, this time showing the situation on the night of November 8, approximately a week after Full Moon. Once again, Mars remains in a perfect location to help us find the constellation Cetus:


Notice that the constellations rise a little earlier each night as we go throughout the year -- thus, by November 8, Cetus is nearing its transit point (the highest place on its arc, as it passes over due south, for observers in the northern hemisphere) around 9:45 pm (or 2145). 

The constellation Cetus plays important roles in many of the world's ancient Star Myths. One important role Cetus plays is the terrible sea-monster sent by the god Poseidon to ravage the kingdom of Aethiopia in order to chastise the pride of Queen Cassiopeia, who boasted that her daughter Andromeda was more beautiful than the divine Nereids of the sea.

In order to appease the wrath of Poseidon and stop the attacks of the Ketos (Cetus), the king and queen were persuaded against their will to chain their beautiful daughter Andromeda to a rock as a sacrifice to the sea-monster. The sea began to boil as the horrifying monster approached the rock where the princess was chained -- but at that moment the hero Perseus was winging his way across the sky on his way home from his successful quest to slay the dreaded Medusa, carrying her severed head in a special sack called the kibesis (loaned to him by the gods, in most accounts by Hermes).

The quick-thinking hero cried out to the beautiful Andromeda to avert her eyes, and then he swooped down and held aloft the terrible head of Medusa. The Ketos was turned to stone by the power of the Gorgon's head, even in death, and Andromeda was saved.

Can you see how Perseus in this particular episode is associated with the constellation Aquarius? Aquarius can be envisioned as holding a pitcher of water, but in many myths this same pitcher becomes a severed head in a sack (see the discussion in my first of two recent conversations with Judith Kwoba of Nightflight -- the second of those conversations can be found here).

I have indicated the location of the constellation Aquarius in the close-up star-chart screenshot above.

There are also two previous posts in which I discuss the connections between the mythical figures in this particular episode -- if you are interested in exploring further, see "Perseus and Andromeda, Revisited!" and "Still more lessons from Andromeda and Perseus."

Those two posts each contain drawings in which I try my hand at depicting the awful moment when the Ketos is approaching the rock where Andromeda is chained, and Perseus flies down to confront the monster while holding the head of Medusa, calling out to Andromeda to look away as he does so. You can see an illustration from William Hogarth done in the 1700s which served as partial inspiration for my efforts, in which the artist clearly positions the sea-monster in the correct location to correspond to the constellation Cetus, Perseus to correspond to the constellation Aquarius, Andromeda to correspond to the constellation Sagittarius, and the mountain-shaped rock to correspond to the constellation Ophiuchus. 

At the top of this post is a painting on a surviving ancient piece of pottery, depicting the same scene, in which Perseus is confronting the Ketos and placing himself between the sea-monster and the princess. Note that in that ancient artwork, the sea-monster is labeled with the name "Ketos" and that its outline corresponds very closely to the outline of the constellation Cetus in the heavens. 

Similarly, Perseus can clearly be seen to correspond to the outline of Aquarius in the heavens in this particular scene, and the ancient artist has depicted the kibesis bag hanging from the lead arm of Perseus, just in front of the enormous head of the Ketos. This corresponds to the fact that the "pitcher" of Aquarius can be seen to be thrust towards the head of Cetus as we look at the constellations in the night sky (look again at the middle of the three star-charts above, which is the "close-up" of the scene, in order to see for yourself).

This famous myth is just one powerful example out of literally thousands which establish beyond any doubt that the world's ancient myths, from virtually every culture on our earth (including the stories in what we call the Bible) are based on celestial metaphor.

I hope that over the next couple of weeks, you will have an opportunity to try to locate the constellation Cetus, if it is at all possible for you to do so. The brilliant planet Mars is presently guiding the way for us to find this important heavenly figure.