A Morning Moon, so long Saturn, hello Mercury, and Aquarius’ Lucky Stars!
The Moon and Planets
Did you see last week’s “perigee syzygy” moon, better known as a Supermoon? This week, the Moon reaches Last Quarter (or Third Quarter) early Monday morning. A Last Quarter Moon has completed three quarters of its orbit around the Earth, making a 90° angle between the Moon, Earth, and the Sun. This may confuse some people, because quarter moons are always half illuminated. So many fractions!
First Quarter Moons are readily visible in early evening because they follow the Sun down in the west, but sharp-eyed observers can spot them earlier, in the daytime afternoon sky. Because they rise before the morning Sun, Last Quarter Moons are visible in the dark eastern sky before dawn. They, too, can be spotted in daytime mornings.
On Monday morning before sunrise, look in the eastern sky to see the Moon sitting only about one finger width to the right of the bright star Regulus the heart of Leo the Lion. Regulus is one of several bright stars located near the Ecliptic which the Moon occasionally crosses in front of, or occults. By the end of this week, the Moon will have waned to a thin crescent that will hop over Jupiter. Both objects are bright enough to see even as the sky becomes light. On Thursday morning, the crescent Moon is a palm’s width to the upper right of the giant planet. The next morning, an even slimmer Moon will sit a smaller distance (about 4°) to the lower left of Jupiter. It’ll be a pretty sight. If you’re up and out on Saturday and Sunday between 5 am local time and sunrise, try to and spot the VERY thin crescent Moon, low in the eastern sky, before it disappears the next day.
Bright, white Jupiter has been rising about three minutes earlier every morning, causing it to sit higher in the eastern sky when the Sun rises. Jupiter rises about 3:15 am local time this week, and the Sun rises about 7:30 am local time. In two months, Jupiter will start rising before midnight.
Mercury and Saturn spend this week within the glow of the western sunset. Mercury is climbing slowly higher and shifting southward, and Saturn is being carried down and to the north — towards the Sun. On Monday afternoon, Saturn is 4° (about four finger widths) above Mercury. On Tuesday and Wednesday, Mercury moves to Saturn’s lower left and slightly closer, then they move apart. By the weekend, the two planets will be arranged in a left-right arrangement, with Saturn a palm’s width to the right. You can hunt for them with binoculars this week, but ensure that the Sun has completely set before doing so! All week, at about 5 pm local time, Saturn will be less than six degrees above the horizon, and descending. They set about 5:30 pm local time.
Next week will be the better one for seeing Mercury, but overall, this evening apparition of Mercury will not be very good for northern hemisphere observers because it sits below an already shallow evening ecliptic, and therefore hugs the horizon. On the other hand, tropical and Southern Hemisphere observers will see Mercury very well indeed.
The planet Venus is still shining with brilliant, white light in the western sky. This week, Venus sets before 7:30 pm local time. In a backyard telescope, Venus exhibits less than a full disk now. It’s a bit more than half illuminated, and waning a little every day.
As darkness settles, bright, reddish Mars is about 24° (two fist diameters held at arm’s length) above the southern horizon. This week it’s amid the stars of Capricornus the Sea-goat. Mars sets about 9:45 pm local time.
Observers with dark skies and keen eyes (or a telescope) can try for dim, blue-green Uranus, which is sitting just inside the western (right) arm of the “V” of Pisces the Fishes. It is low in the eastern sky at sunset and crosses the sky through the night, setting well before dawn. Neptune is sitting about midway between the stars Lambda and Sigma Aquarii in Aquarius the Water-Bearer. It’s in the southeastern sky at dusk, and sets about 1 am local time. I posted a sky chart here.
The Water Constellations — Aquarius and Pisces Austinus
Late autumn evenings feature a grouping of constellations over the southern horizon that share a common theme — the Sea. Collectively known as the water constellations, they aren’t very prominent, consisting mainly of modest and dim stars, but this week’s moonless sky will offer an opportunity to see them better. A few weeks ago I talked about Capricornus the Sea-Goat here. This time, we’ll look at the sea-goat’s neighbours a little to the east and south.
Straddling the ecliptic, immediately to the east (left) of Capricornus is another zodiac constellation, Aquarius the Water-bearer. This is one of the oldest recorded constellations, probably because of its place on the ecliptic / zodiac and because it re-appeared in the morning sky at the time of year that brought the return of desperately needed rains and the flooding of the Nile in ancient Egypt. It’s certainly not because of its stars. Its pattern is made from about 14 modest stars with visual magnitudes near the limit for suburban observers.
Aquarius spans an area measuring about 3.5 outstretched fist diameters wide by 2 diameters high. It is traditionally depicted as a kneeling figure, facing east, who is pouring water from a vessel. A crooked horizontal string of stars represent his right arm outstretched towards the west, his bowed head and shoulders, and his left hand, which bears the jug. This is the most easily seen part of the constellation. Descending from this line is a loose chain of stars representing the flowing water and another representing his torso and legs. In some stories, he’s Zeus pouring out the water of life upon the world. In others, the waters are those of the biblical flood, a story handed down from the Sumerians. As we’ll soon see, the stars of Aquarius are “lucky”.
After darkness falls this month, Aquarius is due south, about halfway between the southern horizon and the zenith. To help you find it, you can use the great square (or baseball diamond) of Pegasus, which sits higher and to the left (east). With “home plate” as the bottom star, extend an imaginary line from third base to first base, and continue in the same direction by the same distance (about two fist diameters) to Aquarius’ highest and brightest star, Sadelmelik.
In a dark sky, up to 100 stars can be counted in the constellation, but only a few are easily seen near city lights. Try to spot the four stars that extend a wide palm’s width from Sadelmalik eastward to the left. One of the four stars sits a couple of finger widths below the line formed by the other three. At the eastern end of the four sits a modest star designated Eta Aquarii. The radiant of the springtime Eta Aquariid Meteor Shower is located close to this star.
Jumping 1.5 finger widths to the right of Eta brings us to a closely spaced double star named Sadaltager “Luck of the merchant” that’s only 91 light-years away. Two finger widths to the lower right of Sadaltager is the white star Sadachbia, which comes from the Arabic phrase sa’d al-akhbiya “lucky stars of the tents”. Then we hop higher again and westward to Sadelmelik, meaning “Lucky stars of the Kingdom”. It is a very mature yellow supergiant star located about 520 light-years away. It’s a bit cooler than our Sun, but about 60 times larger in diameter, making it much more luminous.
Ten degrees to the lower right of Sadalmelik, at the elbow, sits another of the constellation’s brighter stars, Sadalsuud “the luckiest of all of them all”. This is another yellow giant very similar to Sadelmelik and about as distant. Finally, Aquarius’ western hand is marked by a fainter blue-white star named Albali “Good Fortune of the Swallower”, which sits 11° to the lower right of Sadalsuud. The rest of the constellation, dropping down in two crooked lines from the lucky stars, is fairly dim. About halfway along them, both lines take a jog to the left (east).
Aquarius contains only a few significant deep sky objects because it lies away from the Milky Way. The bright globular cluster Messier 2, which can be spotted in binoculars or small telescopes, is only 4° above Sadalsuud. It’s 37,000 light-years away! A planetary nebula named the Saturn Nebula (and also designated Caldwell 55) is located below Albali. At 650 light-years away, it’s among the closest such objects to us. Another one named the Helix Nebula (Caldwell 63) is near the bottom of the constellation. These two stellar corpses are visible in decent backyard telescopes. A second, dimmer globular cluster named Messier 72 is below and between Albali and the Saturn Nebula.
Fittingly, Neptune has been situated in Aquarius since 2011. At present, it sits right between the two dangling chains of stars, about four finger widths to the right of a fairly bright star named Skat. It won’t leave the constellation until about 2022! From mid-December to mid-January, Mars will traverse the constellation. Aquarius sets about 10:15 pm this week. I’ll post a sky chart here.
About a palm’s width below the bottom of Aquarius, due south after dark this time of year, sits a very bright star named Fomalhaut. It’s the 18th brightest star in the entire sky, but it never gets very high for observers in the Great Lakes region. Fomalhaut is the brightest star in an otherwise faint water constellation called Piscis Austrinus the Southern Fish. The constellation is an elongated loop made up of seven stars. It measures 1.5 fist diameters across and half that high, extending westward (right) from Fomalhaut.
Piscis Austinus is depicted as swallowing the poured water of Aquarius, and the two fishes in nearby Pisces are its offspring. It was also recognized by the Egyptians and the Sumerians. Fomalhaut, the mouth of the fish is very interesting. It is a young star only 25 light-years away. The Hubble Space Telescope has been able to capture an image of the star that shows a planetary system forming around it! Fomalhaut sets just after 10:45 pm local time. At 7 pm local time this week, Fomalhaut is about 16° (1.6 fist diameters) above the southern horizon. Find a location with a low southern horizon and see it for yourself!
The Leonid Meteor Shower or Leonids peaked overnight on Wednesday, November 16/17. It runs until November 30th, so you can continue to watch for them, especially now that the Moon has waned and diminished in brightness. The radiant point is within the sickle forming the lion’s head in the constellation Leo, which rises in the east around 1 am local time. The meteors are thought to be leftover material from Comet 55P/Tempel-Tuttle. Leonid meteors are typically fast and bright, with many having persistent trails.
Iridium flares are glints of sunlight off of the flat reflecting sides of one of the satellites that comprise the Iridium pager and sat-phone network. The flares occur before dawn and after dusk, when the satellite passing overhead is still illuminated by the Sun, which is below the horizon for observers on the ground. The duration and brightness depend on the angles between the observer, the satellite, and the Sun. For even more info about Iridium Flares and the space station, see an article that I wrote here. Using an accurate clock, go outside a few minutes ahead and look in the direction indicated. You should first see the dim Iridium satellite moving quickly across the sky, and then it will rapidly brighten for 3 to 8 seconds, and fade out. Truly spectacular! The more negative the Magnitude number, the brighter. The larger the Alt. number, the higher up it is! (The horizon is 0°, and 90° is straight up, so 55° is a bit higher than halfway between the horizon and zenith.) These data are adapted from www.heavens-above.com. To get your own schedule, enter your location in their website.
The ISS (International Space Station) is also visible at times, gliding silently overhead. If you enter your location in the www.heavens-above.com website, you will get a list of them for wherever you might be.)
Stargazing News for this week (from November 20) by Chris Vaughan.