Saturday: Jupiter
is a little more than a half a fist above the Moon at 9 p.m.
Sunday:
The constellation Aquila the eagle is starting its migration across the summer
evening sky this month. Aquila, marked by its bright star Altair, rises to one
fist held upright and at arm’s length above the east horizon at 11 p.m. Not all
animal migrations are fully understood by scientists. We might be inclined to
attribute bird migrations to instinct. This answer certainly did not satisfy
the theologian C. S. Lewis. In his short work “Men Without Chests”, he wrote,
“to say that migratory birds find their way by instinct is only to say that we
do not know how migratory birds find their way”. In science (and theology),
Lewis is telling us to look for real causes and not simply labels such as
instinct. The cause for Aquila’s migration is the Earth orbiting the Sun. As
the Earth moves around the Sun, certain constellations move into the evening
sky as others get lost in the glare of the setting Sun.
Monday: Venus,
Pollux, and Castor make a right triangle two fists above the west-northwest
horizon at 10 p.m. tonight. You know what a right triangle is. You listened to
your math teachers, right? They worked hard for less pay than their intellect
would normally merit. Venus is the very bright point at the bottom of the
triangle. Pollux is above Venus at the right angle.
Tuesday: Late
spring and early summer is a good time to look for star clusters. Last week,
you learned about M3, the third object cataloged by French astronomer Charles
Messier over 200 years ago. One of the best clusters is the globular cluster in
the constellation Hercules, also called M13. (Hummm. Guess what number that
object is in Messier’s catalog.) Globular clusters are compact groupings of a
few hundred thousand stars in a spherical shape 100 light years across. (For
comparison, a 100 light year diameter sphere near out Sun would contain a few
hundred stars.) The globular cluster in Hercules is six fists above the east
horizon at 11 p.m. First find Vega, the bright bluish star about four fists
above the east-northeast horizon. Two fists to the upper right of Vega is a
keystone shape. Aim your binoculars at the two stars that form the uppermost point
of the keystone. The globular cluster is one third of the way south of the
uppermost star on the way to the rightmost star of the keystone. It looks like
a fuzzy patch on the obtuse angle of a small obtuse triangle. If you don’t know
what an obtuse angle is, you should not have told your teacher, “I’ll never
need to know this stuff”.
Wednesday:
While the NASA probe Dawn is off exploring the largest main-belt asteroid
Ceres, you can explore the second largest asteroid Vesta. NASA has released
Vesta Trek, a free web-based application that allows you to zoom in, “fly” over
the surface, measure craters sizes, and see what Vesta looks like in different
wavelengths of light. Go to http://goo.gl/97NxgF
for more information about Vesta Trek and the Dawn mission.
Thursday:
Good night little doggie. Procyon, the brightest star in Canis Minor, the
little dog, is less than one fist above the west horizon at 10 p.m. Over the
next couple of weeks, it will be too close to the setting Sun in the sky to be
visible.
Friday: Saturn
is almost two fists above the southeast horizon at 10 p.m.
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.
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