Saturday: Tonight’s
first quarter moon makes a right triangle with the Beehive Cluster and Jupiter.
Since it is so close to the Moon in the sky, you’ll need binoculars to see the
Beehive Cluster. First find the Moon at 10 p.m. Then look about a half a fist
held upright and at arm’s length to the upper right of the Moon. The other
corner of the triangle, Jupiter, is about a fist to the upper left of the Moon.
Sunday: Mercury
is a half a fist above the west-northwest horizon and Venus is two and a half
fists above the west horizon at 9 p.m.
Monday: Saturn
is a half a fist above the southeast horizon at 11 p.m.
Tuesday: Do
people think you have a magnetic personality? The star Cor Caroli understands
how you feel. Cor Caroli has one of the strongest magnetic fields among main
sequence stars similar to our Sun. This strong magnetic field is thought to
produce large sunspots that cause the brightness of Cor Caroli to vary. Cor
Caroli is nearly straight overhead at 11:30 p.m.
Wednesday:
You know Metis and Thebe and Adrastea and Amalthea. Io and Ganymede and
Callisto and Europa. But do you recall? There are 67 Jovian moons in all. (As
of July 2013.) Just 60 years ago, Jupiter was thought to have only 12 moons.
But, astronomers are red-nosed with delight that the advent of supersensitive
electronic cameras has caused the number of discovered moons to rapidly
increase. Jupiter’s 67 moons range in size from Ganymede, with a diameter of
5,262 kilometers, to S/2002 J12 and S/2003 J9, with a diameter of only one
kilometer. Our moon has a diameter of 3,475 kilometers. (One kilometer is 0.62
miles.) Saturn is second place in the moon race with 62. Uranus is next with
27. Then comes Neptune with 14, Mars with 2, and Earth with 1. Even dwarf
planets have moons. Pluto has 5, Eris has 1, and Haumea has 2. Eris is an outer
solar system object that was discovered in 2005 and named in September of 2006.
Because astronomers thought it was larger than Pluto, people called it the
tenth planet for a while. (More recent measurements show Eris to be a little
smaller than Pluto.) Haumea, the newest dwarf planet with a moon, was
discovered in 2004 and officially named a dwarf planet on September 17, 2008.
Jupiter, the “mooning” champ, is four fists above the west horizon at 9 p.m. Go
to http://goo.gl/Xkoeq for more information about Solar System moons.
Thursday: Avast
ye matey. Swab the poop deck. Pirates love astronomy. In fact, the term “poop”
in poop deck comes from the French word for stern (poupe) which comes for the
Latin word Puppis. Puppis is a constellation that represents the raised stern
deck of Argo Navis, the ship used by Jason and the Argonauts in Greek
mythology. Argo Nevis was an ancient constellation that is now divided between
the constellations Puppis, Vela and Carina. The top of Puppis is about a fist
and a half to the left of the bright star Sirius in the south-southwest sky at
9 p.m. Rho Puppis, one of the brightest stars in the constellation, is about
one and a half fists above the south-southwest horizon at this time.
Friday: Winter
must be over because the winter constellations are becoming less visible. Orion
is setting in the west starting at about 9 p.m. At this time, Orion’s belt is a
little more than half a fist above the west horizon and Betelgeuse is nearly
two fists above the west horizon. By mid-May, Orion will be lost in the glare
of the Sun.
The
positional information in this column about stars and planets is typically
accurate for the entire week. For up to date information about the night sky,
go to http://nightsky.jpl.nasa.gov/planner.cfm.