Astronomy: The Week Ahead – Mon 19 Jan to Sat 24 Jan 2015


Monday January 19

What a treat! Mars and Neptune are 13.35 arc-minutes apart tonight. Mars is easy to spot in the southwest in Aquarius, as the brightest “star” in the area, red and at magnitude 1.16. Neptune will have a blue hue and be easy to see in binoculars at magnitude 7.95. The contrasting colors should be fantastic. Mars is about 186 million miles from us, while Neptune sits 2.79 billion mile away. Inset is an approximately 1 degree field of view showing the pair.


Tuesday January 20

The constellation Eridanus represents a river, and is the Latin name for the Po River in Italy. In a dark sky you can trace its windy course from near the bright star Rigel in Orion, to where it disappears below the southern horizon. As shown in the image, from Orion Headquarters in California Eridanus disappears due south, hiding its brightest star Achenar which marks the end of the celestial river’s course. The ancient astronomer Ptolemy created the constellation in the 2nd century. Among the 88 modern constellations, Eridanus is 6th largest.


Wednesday January 21

Morning observers can grab a view of the Ring Nebula, Messier 57 (M57), before dawn. It is very easy to locate in the constellation Lyra, between the end stars of a parallelogram near the bright star Vega. While your view will not show color, the view of this planetary nebula will look much like a smoke ring. It is an easy object in a telescope, but challenging in binoculars.


Thursday January 22

Do you know the two types of star clusters? Globular clusters are ancient and distant. Open clusters are close and young. The Pleiades is an easy-to-see young open cluster above Aldebaran in Taurus, which is just above Orion. As open clusters age, their stars spread out. The Hyades, also in Taurus, is an older open cluster. Its stars are around the bright stars Aldebaran. An even more spread out open cluster is the Alpha Persei Moving Group, which contains the bright star Mirfak in Perseus. Many of the brighter stars around Mirfak are part of that old group. The Big Dipper is another old and spread out open cluster.


Friday January 23

Tonight features a terrific triple shadow transit on Jupiter! These are a rarity, so if you can set up a telescope and view it, you’ll have a real treat. The image at left shows all three shadows of Jupiter’s moon Callisto, Io and Europa on the disk of the planet. Note two of its moons (Callisto and Io) also on the disk, and the Great Red Spot is visible. Here are start and end times (PST):

Callisto Shadow 19:03 00:11
Io Shadow 20:33 22:53
Europa Shadow 22:24 01:24


Saturday January 24

NGC 4565 is a prototype edge-on spiral galaxy. It is bright enough to be seen in any size telescope from darker sites, currently in predawn skies.

Once you see this galaxy, you’ll love it. Its spindle arms and small bright core are obvious. You should also see its dust lane bisecting the core.

It is part of the Virgo Galaxy Cluster, which averages a distance of 45 million light years from us.

Happy viewing & have a great week!