August 02, 2020

Mars, Jupiter and Venus will set stage for January planet-watching

Maine Skies

A powerful new telescope has just been added to the astronomer’s arsenal. Last Oct. 31 the ninth hexagonal mirror segment was fitted into the Keck telescope in Hawaii making it larger than California’s 200-inch Palomar reflector. Each segment is nearly 71 inches (1.8 meter) in width. Ultimately, the Keck telescope will have a primary mirror 10 meters wide, exactly twice the size of the Palomar mirror. Efforts have just begun to capture the first images through the new telescope. A mid-November snowstorm (yes, in Hawaii!) hampered efforts atop Mauna Kea with computer glitches causing further delays. Nonetheless, astronomers hope to have all 36 mirrors in place by the end of 1991.

The Keck telescope will be administered jointly by the University of California and Caltech. It represents the culmination of a 13-year dream by astronomer Jerry Nelson who, in 1977, convinced his colleagues that a new mirror should be constructed, not as a single massive piece of glass, but as a mosaic of hexagonal glass tiles. The Keck will have several advantages over existing scopes. For one, it will have good sensitivity at infrared wavelengths where the light from young, red-shifted galaxies is found. For another, its enormous size will allow it to find and study faint objects. According to Wallace Sargent of Caltech, the Keck mirror will cut his focusing time on certain quasars from 10 hours to 30 minutes. Look for the first images from the Keck telescope to be appearing shortly.


Three bright planets, Mars, Jupiter, and Venus, set the stage for viewing in January’s skies.

MARS is high overhead as darkness falls in January. Look for the reddish-orange planet among the bright stars of Taurus and near the Pleiades. Early in the month it outshines nearby Aldebaran but will fade as the month progresses.

JUPITER reaches opposition, and is at its brightest, on Jan. 28. All during January the gas giant may be found in the northeast at nightfall. The hazy patch near Jupiter is the Praesepe or Beehive star cluster.

VENUS was lost in the sun’s glare last autumn and is making its first return to the night sky since the fall of 1989. Look for it low in the southwest shortly after sunset.

SATURN is just north of Venus as the month opens. It is much fainter than its neighbor, however, and will shortly disappear as it journeys behind the sun.

MERCURY is visible all month in the pre-dawn sky. Look for it in the southeast about an hour before sunrise. The bright star above and to the right of Mercury is Antares.

PLUTO is in the southeastern sky just before dawn and, with luck and a good telescope, may be spotted near the constellation Libra.

URANUS and NEPTUNE are lost in the glare of the Sun during January.


Canis Major, the “Great Dog,” lies to the lower left of Orion the Hunter and is one of his hunting dogs. In mythology the dog is standing on its hind legs attempting to capture Lepus the Hare. There are 14 easily visible stars making up Canis Major but Sirius, the Dog Star, outshines them all, literally and in legend. Sirius is the brightest star in the sky and was worshipped in ancient Egypt because its appearance in the June pre-dawn sky signaled the annual flooding of the Nile River. It later became associated with the heat of summer, hence the name “dog days” to those unbearable days in July and August. Sirius is half of a binary system being a blue-white giant being circled by an invisible white dwarf companion and in this lies a fascinating tale. In the 1940s two French anthropologists were studying the primative Dogon tribe and were supposedly told this story. Sirius, said the Dogon, was not one but two stars with the other being a dark unseen companion they called Digitaria. This, “the beginning and end of all things,” was the smallest and heaviest object in the skies. How a primitive tribe of natives could have ever heard of, let alone develop a mythology around, a star known only to a handful of astronomers, remains a mystery to this day.


1. Sunrise, 7:13 a.m.; sunset, 4:05 p.m. Celebrate the new year by looking for Venus just above the southwest horizon at sunset. Once you’ve found Venus, Saturn is to the upper right.

2. The Earth is at perihelion, its closest approach to the sun for the year. Aphelion, Earth’s furthest point from the sun, comes in July.

7. Moon in last quarter, 1:36 p.m. The moon rises around midnight and is high in the south by dawn.

12. The waning crescent moon is very near Antares at dawn.

15. New Moon, 6:50 p.m.

17. A thin, waxing crescent moon shines just above Venus low in the west at twilight.

18. Mars is just south of the Pleiades tonight.

20. Sun enters the astrological sign of Aquarius but, because of precession, astronomically is entering Capricornus.

25. The waxing gibbous moon is just north of Mars tonight.

28. Jupiter is at opposition and moves from the morning into the evening sky. It rises at sunset, shines all night, and sets around sunrise.

30. Full Moon, 1:10 a.m. The full moon of January is called the Old Moon or the Moon After Yule. A penumbral eclipse of the moon, in which the moon passes through the outer fringe of the Earth’s shadow, occurs tonight. This is likely to be too faint to be observed.

31. Sunrise, 6:56 a.m.; sunset, 4:42 p.m.

Clair Wood, a science instructor at Eastern Maine Technical College, is the NEWS science columnist.

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