Astronomy: The Week Ahead – Sun 26 Jan to Sat 31 Jan


Sunday January 25

Here is a view of tonight at 8 p.m. via PST. The Moon is between the constellations Gemini and Cancer. Notice the two circles, one inside the other, near the center of Cancer. If you know what they are then you’ll also know they are always present, can be seen visually, and are constantly in motion.


Monday January 26

Today the Moon reaches its First Quarter phase. Moon phases begin at New Moon, when the Moon is too close to the Sun to be viewed. The lunar month begins with waxing crescent, waxing meaning getting (visually) larger. Today it changes from crescent to gibbous; over half the Moon illuminated by the Sun. After Full Moon, it begins waning, and is less illuminated each night. The waning gibbous Moon changes to a waning crescent as it passes through Third Quarter, as it continues on toward the next New Moon.

Also, on Monday evening January 26th, it will become the largest asteroid to pass closest to Earth until 2027 when 1999 AN10 will approach within one lunar distance. (See:  Astronomy: Big Asteroid 2004 BL86 Buzzes Earth on Monday 26 January)


Tuesday January 27

Morning observers can find the Sunflower Galaxy, M63 high in the northwest, in the constellation Canes Venatici, the Hunting Dogs. Using the constellation’s one bright star, Cor Caroli (The Heart of Charles), and the end star of The Big Dipper as reference points, it is easy to star hop to.

The galaxy is bright at magnitude 8.6, and will be visible from darker locations in binoculars and any telescope. It will appear elongated and containing a bright core. It is part of the same galaxy group at M51, The Whirlpool Galaxy, and at a distance of about 35 million light years.


Wednesday January 28

This morning before sunrise look for the constellation Serpens Caput in the southwestern skies. It will be directly above Saturn. An easy way to find it is along the line of stars the define the lower part of Ophiuchus, as they point to Serpens Caput’s brightest star, Unukalhai, which is a double star. The name Unukalhai translates from Arabic as “The neck of the serpent”. It is also called Cor Serpentis, the heart of the serpent.

Serpens is broken into two parts, on opposite sides of Ophiuchus, the Serpent Bearer in Greek mythology. Caput is on the western side and Cauda to the east.


Thursday January 29

An hour after sunset you can see Jupiter rising near the eastern horizon, and a bright waxing gibbous Moon in Taurus near Aldebaran. Note the green line crossing upward from near Jupiter. It is the ecliptic, the path of the sun through our skies. Constellations along the ecliptic are the signs of the Zodiac.

The Moon and planets follow the ecliptic, but wander north and south of the sun’s path. The Moon tonight is south of the ecliptics, Jupiter slightly to its north.


Friday January 30

With a large bright Moon in the sky, near Orion and Gemini, let’s look away, to the north for a nice bright target.

M103 is a beautiful small jewel of an open star cluster, in Cassiopeia. Even binoculars will reveal its three brightst stars, magnitudes 7 and 8, in an almost straight line, with hints of nebulosity. Overall, it is bright (magnitude 7.4) and small, occupying only 6 arc-minutes, and rich. One experienced observer counted 28 stars in the cluster in a 13″ telescope, noting a nice chain of of 10th magnitude stars along its northeast side.


Saturday January 31

Tonight Jupiter treats us to two very good shadow transits, with interesting timing! Start by finding the Great Red Spot near meridian at 22:26 PST. Two minutes later Io’s shadow begins ingress on Jupiter’s disk. The Moon itself will ingress ten minutes later. Io’s shadow will end its transit at 00:45, and Io at 00:56. In another seven minutes you’ll see Europa’s shadow transit begin.

Happy viewing!