Mars is Moving, Leftover Leonids, a Full Frost Moon, and November’s Brightest’s Lights!
Leonids Meteor Shower Leftovers
Meteor shower season continues! Over the next few months, we’ll experience a wave of several showers. The Leonids Meteor Shower, which is derived from material dropped by repeated past passages of Comet 55P/Tempel-Tuttle, peaked this morning (Sunday), but you should still keep an eye out for fewer Leonids during the next several nights as Earth makes it way out of the debris field.
The meteors can appear anywhere in a dark sky, but true Leonids will be travelling in a direction away from a location (the radiant) just above the stars that form the head of Leo (the Lion). To see the most meteors, find a wide-open dark location, preferably away from light polluted skies, and just look up with your unaided eyes. Binoculars and telescopes are not useful for meteors — their field of view are too narrow. Happy hunting!
The Moon and Planets
This week, the moon will continue its trip across the evening sky as it waxes towards Friday’s Full Frost Moon. Pull out your binoculars and telescopes and take a look! Low-angled sunlight will illuminate peaks and crater rims while casting deep black shadows from them. It will also reveal subtle topographic features that are otherwise invisible, such as ridges and cracks on crater floors. New sections of the moon will be highlighted every night as the terminator, the boundary line that separates the lit and dark hemispheres, migrates from lunar east to west.
To start the week, the moon will pass through the dim water constellations of Pisces (the Fishes) and Cetus (the Sea-Monster) until Wednesday. Then it will cross Aries (the Ram), Taurus (the Bull), and the raised club of Orion (the Hunter) — ending up next Sunday evening in the sky between the legs of Gemini (the Twins).
Friday’s November full moon, also known as the Beaver Moon, always shines in or near the stars of Taurus (the Bull) and Aries (the Ram). Since the moon sits opposite the sun on this day of the lunar month, it will rise at sunset and set at sunrise. Full moons during the winter months in North America climb as high in the sky as the summer noonday sun, and cast similar shadows.
The maria, Latin for “sea”, are the large darker regions visible on the moon’s near side. They are basins formed by major impacts early in the moon’s geologic history and later filled with dark basaltic rock that welled up from the interior of the moon. The small, round crater Plato, which sits above Mare Imbrium, and crater Grimaldi, just to the southwest of Oceanus Procellarum, have both also been filled with lunar basalt, making them mini-maria.
This week, Mercury will be positioned very low in the southwestern sky, visible with difficulty for a very short time after sunset. Both Mercury and Jupiter will soon cross to the western side of the sun and join Venus in the eastern pre-dawn sky.
Even though it is continually dimming as Earth pulls farther away from it, reddish Mars will be the brightest celestial object the southern evening sky this week, besides the moon. Look for Mars as a bright, reddish, star-like object shining in the lower half of the southern sky after dusk. Mars will set in the west just before midnight local time.
Dimmer, yellowish Saturn will be located six fist diameters to the lower right of Mars this week. But it will set soon after 7 pm local time, so don’t leave it too late to look for it. After the sky has darkened, even a small telescope should be able to show you some of Saturn’s larger moons beyond the planet’s rings, especially the largest satellite, Titan. Using a clock’s dial analogy, Titan will move counter-clockwise over the course of this week — starting from a position at 11 o’clock (to the upper left of Saturn) and ending up next Sunday at 6 o’clock (below Saturn). (Remember that your telescope might flip and/or invert the view. Use the moon to find out how your telescope changes the image and make a note of it.)
Mars’ orbital motion has been carrying it eastward, directly towards distant Neptune. Tonight, Mars will be located about 1.2 fist diameters to the right (west) of Neptune. Next Sunday night, Mars will be only half that distance away from the blue, ice giant planet. All week long, Neptune will be visible after dusk, and it will set at about 12:30 am local time. Using binoculars or a telescope, look for the magnitude 7.8 planet sitting about two finger widths to the left of the modestly bright star Hydor (Lambda Aquarii). Neptune will highest in the southern sky (and at the best viewing conditions) at about 7 pm local time.
Blue-green Uranus (“YOU-ran-us”) is farther to the east than Neptune. It’s still close to its peak brightness (magnitude 5.7) and size for this year. You can see Uranus without optical aid under very dark skies, but binoculars and telescopes will make seeing it easier. Look for Uranus less than 2 finger widths to the left (east) of the modestly bright star Torcular (Omega Piscium). That star sits a generous palm’s width above the “V” where the two starry cords of Pisces (the Fishes) meet. By mid-evening, Uranus will be high enough in the southeastern sky to see it clearly.
Yesterday, Saturday, November 17, the major main belt asteroid Juno reached opposition. At opposition, Earth passes between the asteroid and the sun, minimizing our distance from Juno and causing it to appear at its brightest and largest for this year. This week, the magnitude 7.45 object will be visible in binoculars and small telescopes all night long after it rises in the east at 6:30 pm local time. Juno will be positioned about two fist diameters from the bright stars Aldebaran in Taurus (the Bull) and Rigel in Orion (the Hunter). It will reach its highest position, about halfway up the southern sky, at midnight local time.
Our final visible planet, very bright Venus, will be shining in the morning pre-dawn eastern sky all winter long. This week, Venus will be located only about two finger widths to the lower left of the bright white star Spica in Virgo (the Maiden) and drawing farther away from that star every morning. In a telescope, Venus will exhibit a slender crescent. Despite the tiny fraction of its surface reflecting sunlight towards us, Venus remains so bright because of its relative nearness to Earth.
The Brightest Stars of November
The stars that make up the major winter constellations of Orion, Taurus, and Gemini are bright enough to see during moonlit nights, even under mildly light-polluted skies. In fact, when Sirius rises in the east-southeast at about 10:30 pm local time, six of the top ten brightest stars in the entire night sky will be visible by observers in mid-northern latitudes worldwide. Let’s tour the brightest stars. (I’ve put their bright star rankings in parentheses — not counting the sun.)
After Sirius (1st), the brightest star in Canis Major (the Big Dog) rises, it will be hard to miss. The star will climb to its highest point, about a third of the way up the southern sky, at 3 am local time. If you are walking through your darkened house in the middle of the night, this star will probably catch your eye out a window because it never climbs very high. Sirius’ brightness and low position in the sky combine to produce spectacular flashes of colour as it twinkles.
Meanwhile, in the western sky at 10:30 pm local time, very bright Vega (5th) in Lyra (the Harp) will be descending toward the horizon. Altair (12th) in Aquila (the Eagle) will be even lower and off to Vega’s left — preparing to set as Sirius rises. Deneb (19th) in Cygnus (the Swan), which complete our Summer Triangle trio of hot white stars, will be more than two fists higher, and positioned between the other two stars.
Observers with a very low southwestern horizon might be able to see Fomalhaut (18th) in Piscis Austrinus (the Southern Fish).
The rest of the brightest stars are in the eastern sky. Yellowish Capella (6th), in Auriga (the Charioteer) is the brightest and highest of our eastern sky bright lights, having risen before dusk. Reddish Aldebaran (14th), which marks Taurus the bull’s southern eye, will be located three fist diameters to the right of Capella. Blue-white Rigel (7th), which marks the western foot of Orion will be positioned about midway between Aldebraran and Sirius. Orange-red Betelgeuse (10th) marks the eastern shoulder of Orion. It occupies a position about two fist diameters to the upper left of Rigel.
Procyon (8th), in Canis Minor (the Little Dog), is located higher than Sirius, and about 2.5 fist diameters to its left. Our last bright November evening star is Pollux (17th), which marks the head of the eastern (and lower) sibling of Gemini. Pollux is positioned farther left than Procyon, and about 3.5 fist diameters below Capella. By the way, Castor (24th) marks the other twin’s head, and is about four finger widths above Pollux. To help you remember which is which, note that Castor comes first in an alphabetical list and also rises before Pollux.
Stars appear brighter for two primary reasons. They can be inherently more luminous (i.e., emitting more visible light) and/or they can be closer to us. Two of the stars noted above, Sirius and Procyon, are only about 10 light-years away from our sun. Vega, Altair, Pollux, and Fomalhaut are less than a few dozen light-years away. Betelgeuse is 640 light-years away. Amazingly, Deneb is a whopping 2,600 light-years away! It’s producing a prodigious amount of visible light to appear so bright from such a distance!
Astronomy Skylights for the week of November 18th, 2018 by Chris Vaughan.
Keep looking up, and enjoy the sky when you do. I love questions and requests — so, send me some!