Newsletter February, 2022
Mountain Skies - Dr Bob Hayward, Astronomer & Educator
PLANETARY TRAFFIC JAM
The planets: There are five, maybe six, planets we can see with our naked eyes. Five of these, i.e., Mercury, Venus, Mars, Jupiter and Saturn are called the “classical” planets since they were known to ancient scholars of the sky. I said “maybe six” because the planet Uranus is technically right on the edge of being a visible planet under ideal sky conditions for an observer with good eyesight. But the ancients didn’t notice that this very faint “star” was moving and, thus, did not recognize it as a planet or “wandering star.” They considered anything that moved in the sky to be a planet, so they included the sun and moon. That makes seven classical planets each one to rule its own day of the week. I’ve often wondered if the ancients had recognized Uranus as one of their classical planets, would we now have an 8-day week? Where would you put the eighth day? When I ask school children that question, I usually get a resounding “on the weekend.”
So where are these seven “planets” now? The sun is obvious to you…at least I hope so. The moon’s phases this February neatly straddle the whole month. We have a new moon on the 1st, full moon in the middle of February and the next new moon just over the line on March 2. But the classical planets don’t follow such an obvious calendar. Right now, the giant Jupiter is low in the west as the sun sets. It is the brightest object in our evening sky except for the moon which, for the first week of the month, stands above the planet. But Jupiter is quickly disappearing into the evening twilight and will pass behind the sun in superior conjunction on March 5. It will then join three of the other four classical planets in the evening twilight by April Fools Day.
The other five planets are now in a traffic jam low in the southeast before sunrise. To spot them, start with the brilliant Venus which is moving eastward low in the southeast just above Sagittarius. Below Venus is the red planet Mars. For the time being they are moving eastward together. But in June they will separate with Mars moving into our evening sky while Venus continues to reign as our “Morning Star.” Mercury, since it is close to the sun, moves quickly. On the 9th it will be at its highest point above our horizon. In March it dives into the morning twilight to pass behind the sun on April 2. Saturn hangs around in Capricornus east of the other three but is deep in the twilight and very difficult to spot. However, by the end of the month the ringed planet will be higher in the morning twilight. The month ends with Mercury, Saturn and the moon bunched together in Capricornus, Venus and Mars racing eastward out of Sagittarius and Jupiter lost in the glare of the sun.
Observing Challenge: All month, Venus and Mars lie in Sagittarius very low in the southeast in the morning twilight. Early in the month, look for the elusive Mercury below these two (a challenge to spot in the brightening twilight). By the 24th the waning crescent moon joins the show in the south next to the bright red star Antares, the heart of the scorpion. Over the next three mornings the moon moves through Sagittarius and, on the morning of the 27th, lies directly below the bright “morning star” Venus with the red planet Mars between the two.
The stars: Remember Orion the hunter, the brightest constellation in the entire sky and the key figure in the winter? He’s standing well up in the south. Now, go to the belt of Orion and draw a line to the east. Well up in the southeast is a bright white star. This is Sirius the Dog Star. While Sirius appears to be the brightest star in the nighttime sky, it is not intrinsically the most luminous nor is it the closest to us. But it is a combination of both so that it appears to be the brightest; it is a white-hot star that is a little less than nine light years away, close as stars go. Sirius was known as Sothis to the ancient Egyptians and was an important star to them because, when it rose just before the sun, called a heliacal rising, it foretold the pending flood of the Nile River. It also gives rise to our term “dog days of summer.”
To the north of Orion’s great dog Canis Major, lies the dimmer but still quite noticeable star Procyon. As the risings of Sirius and Procyon are observed from mid-northern latitudes, Procyon comes up just before Sirius; thus, Procyon means “He who precedes.” Procyon is the brightest star in the constellation of the little or lesser dog, Canis Minor, sometimes dubbed “The Pup.” In all this small constellation there is only one other moderately bright star, Gomeisa. Thus, Canis Minor looks less like a puppy than a hot dog. A triangle formed by the red star Betelgeuse in the shoulder of Orion with these two dog stars, Sirius and Procyon, is known as the Winter Triangle.
Graphic produced by permission with TheSky Astronomical Software, Software Bisque
- February 1, 12:46 a.m. EST – New Moon
- February 8, 8:50 a.m. EST – First Quarter Moon
- February 16 – The Sun moves from Capricorn the sea-goat into Aquarius the water-bearer.
- February 16, 11:57 a.m. EST – Full Moon
- February 23, 5:32 p.m. EST – Last Quarter Moon
About PARI
About PARI: The Pisgah Astronomical Research Institute (PARI) is a public not-for-profit 501(c)(3) organization located in the Pisgah National Forest 30 miles southwest of Asheville, NC. PARI offers STEM camps, astronomy research, and satellite business services that inspire and empower everyone - from students to scientists - to reach the next frontier. www.pari.edu
