Saturday: Hit
the road Mercury. And don’t you come back no more, no more. For a few weeks,
Mercury has been hitting the road and moving away from the Sun in the sky.
Today, Mercury is as far away from the Sun as it will get on the evening half
of this cycle. This is known as its greatest eastern elongation. Yet, this
distance does not translate into good viewing because Mercury will be very low
in the sky. Mercury is less than a half a fist held upright and at arm’s length
above the west-northwest horizon at 9:10 p.m. Over the next few weeks, Mercury
will move toward the Sun in the sky. After it passes in front of the Sun, it
will appear in the morning sky by early September.
Sunday: At
9:50 p.m., Jupiter is one fist above the west-southwest horizon and Saturn is
two fists above due south.
Monday: Do
you want an easy way to find due north? A compass points to magnetic north,
which is a few degrees off of true geographic north. Well, tonight’s your
night. Capella, the brightest star in the constellation Auriga the Charioteer,
is due north at exactly 9:39 p.m. It looks like a bright light on a pole on the
north ridge because is only about three degrees above the horizon.
Tuesday: In
Scotland, August 1 was known as Lammas, the festival of the first wheat harvest
of the year. You can remember this by looking at Spica, named after the Latin
word for “ear of wheat”, one fist above the west-southwest horizon at 9:30 p.m.
August 1 is known as a cross-quarter day, a day approximately half way between
an equinox and a solstice.
Wednesday: It’s
a moonless August morning. The first remnant of dawn has not appeared yet. Suddenly,
you notice a large softly radiant pyramid of light in the east sky. The base of
this ghostly triangle is along the east horizon and the peak stretches two or
three fists held upright and at arm’s length above the horizon about two hours
before sunrise. Don’t be scared. It’s not really a ghost. It is an effect
called the zodiacal light. This light comes from sunlight reflecting off dust
grains in our solar system. The effect is the most visible when the band of
constellations called the zodiac makes a steep angle with the horizon. You need
a clear dark sky with no haze or light pollution to see the zodiacal light. At
its brightest, the zodiacal light rivals the light of the central Milky Way.
This is one of the best times of year to see the zodiacal light in the morning.
This is also one of the best times of the year to see meteors. The Perseid
meteor shower peaks in a week and a half. But you should see increased meteor
activity for the next three weeks just below the W of the constellation
Cassiopeia. This point is about two and a half fists above the northeast
horizon at 11 p.m. By dawn, this point is about seven fists above the northeast
horizon.
Thursday: NASA
just developed a faster and more cost-effective way to send a probe to a large
solid metal asteroid. Psyche! Oh…. Did you think I was using the word “Psych”
for its urban dictionary meaning of negating the statement before it? As in,
“The writer of this column is a really smart guy. Psych.” No, NASA did just develop
way to put a probe in orbit around the solid metal asteroid called Psyche four
years earlier than originally planned. Thanks to a new five-panel x-shaped
design for its solar array, NASA’s Discovery will gather more energy from the
Sun and avoid the need for an Earth gravity assist. For more information about
the Discovery
mission to Psyche, go to https://goo.gl/rG6Qh7.
Friday: Venus
is two fists above the east horizon at 5 a.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 https://nightsky.jpl.nasa.gov/planner.cfm.
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