Saturday: Jupiter and Saturn are about two fists above the south-southeastern horizon at 9:00 p.m. Jupiter is the much brighter of the two. Saturn is about one and a half fists to the right of Jupiter, which is about one and a half fists to the upper right of the Moon. When you are looking at this part of the sky, you are looking in the direction of more than just the two planets. You are also looking in the direction of their moons. Titan, Saturn’s largest moon, is easily visible with a small telescope, about five “ring diameters” to the side of Saturn at this time. Jupiter’s four largest moons are also visible with a small telescope. Calisto and Ganymede are on one side of Jupiter, with Ganymede appearing the farthest away. Europa is visible in the other. If you have very clear skies, you may see Io on the Europa side, right next to Jupiter. Recently, a team of Canadian astronomers analyzed images of Jupiter from 2010 and estimated that Jupiter could have 600 moons at least 800 meters, a half mile, in diameter. They didn’t actually discover these moons. They just formulated a possible model of the Jovian system. For more on this, go to https://skyandtelescope.org/astronomy-news/jupiter-could-have-600-moons/.
Sunday: The bright star Capella is two fists above due
northeast at 11:00 p.m.
Monday: Shine on, shine on harvest moon, up in the sky. It’s
just like a full moon in January, February, June and July. The only difference
is that near the Autumnal Equinox (also known as the first day of fall), the
full moon rises close to sunset resulting in a full night of light for the
harvest. The harvest moon looks more orange than usual when it is near the
horizon because of the dust kicked up from the harvest. The dust scatters the
white light reflecting off the Moon resulting in slightly more of the red
and orange components of the white light reaching your eyes. Although the Moon
has a dull yellow color whenever it is near the horizon owing to light
scattering off dust and atmospheric particles, the effect is more noticeable
for the harvest Moon. For more information about the harvest moon, go to https://earthsky.org/astronomy-essentials/harvest-moon-2/.
Tuesday: According to the “One world, group hug, love
everyone” philosophy, political borders are human-made and can’t be seen from
space so why can’t we all just get along. According to real world pragmatic
discoveries, some human-made political borders CAN be seen from space. Since
2003, India has illuminated its border with Pakistan to prevent illegal
crossings. In 2011, astronaut Ron Garan took a picture of that border from the
International Space Station. For more information, including the photo, go to http://goo.gl/mY8xG.
Wednesday: At 12:22 p.m. PDT, the center of the Sun crosses
the celestial equator and passes into the southern sky. The celestial equator
is an imaginary line that divides the sky into a northern and southern half.
When the Sun is in the southern half of the sky, it appears to take a shorter
path from rising to setting. It also does not get as high in the sky at noon.
This leads to shorter days and longer nights. Since the Sun crosses the
celestial equator today, there is an instant when it is equally in the northern
and southern sky, called the north and south celestial hemispheres. This
so-called “equal night” is given by the Latin word equinox. Thus, today is
known as the Autumnal Equinox. However, the day and night are not of equal
duration today. The sun rises at 6:50 a.m. and sets at 6:59 p.m. in the
northern latitudes of the United States. At these latitudes, day and night are
closest to equal duration on Saturday.
Thursday: Last year, astronomers announced that they
detected phosphine, a possible biosignature of life, in the upper atmosphere of
Venus. Although the surface of Venus is inhospitable, astronomers have long
speculated that the upper atmosphere could harbor life. Not Cloud City life
from The Empire Strikes Back but maybe cellular life. But more recent studies
show that the original scientists just found the signature of sulfur dioxide, a
gas common on Venus. This recent phosphate news is an excellent example of
science at work. In less than a year, science went from “we may have found a
marker for life on Venus” to “it is unclear if we found a marker for life” to
“we probably didn’t find a marker for life”. Do an internet search of the words Venus and phosphine and read the articles to follow the story. To get yourself
in the mood, go outside at 7:45 p.m. Venus is a half a fist above the
southwestern horizon at this time.
Friday: The bright star Vega is about five fists above the
western horizon at 11:00 p.m. Its fellow Summer Triangle star Deneb is about
two fists above it. Altair, the third star in the triangle, is about four fists
above the southwestern horizon.
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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