There is one river seen from New Brunswick that is completely ice-free all winter, but we can only see it at night. Eridanus the River, the fifth largest constellation in area of sky, has its head just off the foot of Orion near Rigel. Even when it is at its highest in our sky, the river’s meandering path takes it more than ten degrees below the horizon to where it terminates at Achernar, the ninth brightest star.
In mythology the river is associated with Phaethon, a mortal son of Apollo. Apollo drove the Sun, a golden chariot powered by mighty steeds, across the sky by day. Phaethon was allowed to drive it one day but he couldn’t control the steeds. They ran amok, scorching the sky (the Milky Way) and the Earth (Sahara), until Zeus blasted Phaethon with a thunderbolt and he fell to his death in the river. The twisty constellation was also considered to be the path of souls.
Although we can’t see Achernar without travelling to Florida, there is a notable star in Eridanus that we can see from outside a city. Omicron-2 Eridani, also called 40 Eridani or Keid (circled on the map), has a famous fictional and fascinating planet: Vulcan, the home of Spock. Did you know that there was once believed to be a planet closer to the Sun than Mercury? It was named Vulcan after the Roman god of fire, metalworking and the forge. Anomalies in Mercury’s orbit were thought to be due to an interior planet, and some astronomers even claimed to have seen it crossing the Sun. This was about 150 years ago, after Neptune was predicted and discovered based on anomalies in the orbit of Uranus. Coincidentally, regarding the god Vulcan, the constellation Fornax the Furnace barely crests our horizon near Eridanus.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 7:55 am and sunset will occur at 5:03 pm, giving 9 hours, 8 minutes of daylight (7:58 am and 5:11 pm in Saint John). Next Saturday the Sun will rise at 7:49 am and set at 5:13 pm, giving 9 hours, 24 minutes of daylight (7:52 am and 5:20 pm in Saint John).
The Moon is at third quarter on Friday, January 17, and it passes near Mars on Monday and Jupiter Wednesday before reaching new Moon phase next Friday. Jupiter rises an hour before the Sun this week and about two hours after Mars. Venus rules the early evening sky, easily cutting through bright twilight in the southwest, while Mercury begins its best evening apparition for the year, setting 45 minutes after sunset by next weekend.
The provincial astronomy club, RASC NB, meets in the Rockwood Park Interpretation Centre on January 18 at 1 pm. There will be public observing at the Mactaquac Park office, across the road from the park entrance, in the early evening of Saturday, January 25. All are welcome.
Questions? Contact Curt Nason at firstname.lastname@example.org.
This Week’s Sky at a Glance, 2020 January 11 – January 18
With Orion’s hourglass figure now above the horizon after sunset, the giant hunter waits an hour or so for his two dogs to get up before he starts hunting. The first to greet the night is Canis Minor the Little Dog, a small constellation highlighted by Procyon, the eighth brightest star. To identify this star, Orion’s head and shoulders form an arrowhead, with orange Betelgeuse at the apex, which points toward Procyon. Like Sirius in Canis Major, this star is bright because it is in our celestial backyard, about 11 light years away.
The name Procyon means “before the dog,” indicating it is a harbinger of Sirius the Dog Star which rises about 40 minutes later. Ancient Egyptian farmers watched for the first visible rising of Sirius before sunrise, as experience had taught them the Nile would soon flood its banks with fertile soil when this occurred. In mythology the two dogs are sometimes depicted as Laelaps (Canis Major), an extremely fast dog, and an equally fast fox (Canis Minor). The dog was sent to hunt the fox but, after a long chase with no apparent end, Zeus turned them both to stone and placed them in the sky.
I like to look at the dogs and their westerly neighbours, Orion the Hunter and Lepus the Hare, in a more modern sense. The mighty demigod Orion becomes everyone’s favourite hunter, Elmer Fudd, with that wascawwy wabbit bugging him below his feet. The big and little dogs become Spike and Chester,who were also part of the Looney Tunes gang. Just as Chester would bounce around in front of his hero, the bulldog Spike, Canis Minor bounces up before Canis Major.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 7:59 am and sunset will occur at 4:54 pm, giving 8 hours, 55 minutes of daylight (8:01 am and 5:02 pm in Saint John). Next Saturday the Sun will rise at 7:55 am and set at 5:03 pm, giving 9 hours, 8 minutes of daylight (7:58 am and 5:11 pm in Saint John).
The Moon is full on Friday, January 10, and it is at perigee on Monday, giving high tides this weekend. Next Friday the Moon is at third quarter. The eastward motion of Mars relative to the stars will bring it within a binocular field above its namesake star, Antares; the red supergiant star in the heart of Scorpius the Scorpion. Compare their colour and brightness in the southeast before morning twilight. Jupiter rises about 45 minutes before sunrise midweek. Venus rules the early evening sky, easily cutting through bright twilight in the southwest. Mercury and Saturn are passing behind the Sun in opposite directions this weekend. Not to be outdone, dwarf planets Pluto and Ceres are following Saturn’s lead.
The William Brydone Jack Astronomy Club meets in the UNB Fredericton Forestry-Geology building on Tuesday at 7 pm. The provincial astronomy club, RASC NB, meets in the Rockwood Park Interpretation Centre on January 18 at 1 pm. All are welcome.
Questions? Contact Curt Nason at email@example.com