below are notable astronomical events coming up for the month of
In September, Mercury begins the month in the evening sky, close
to 20 degrees from the Sun. Unfortunately, almost none of that translates
to height above the Sun over the western horizon after sunset. Therefore
Mercury will be very difficult to see at that time, and indeed throughout
the rest of the month. Although Mercury reaches greatest elongation
on the 21st, binoculars and a VERY flat western horizon will probably
be required to view Mercury within the fringe of the light of sunset
for the month.
Venus is in the morning sky all month long in September, starting
in the constellation Leo. Venus will start the month rising very
low over the eastern horizon before the sky lightens from dawn.
Seeing Venus will become more difficult all month long as Venus
rises ever later, and therefore deeper in the Sun’s glare.
By the end of the month Venus rises in Virgo and less than 10 degrees
away from the Sun. This will probably be the last month for a while
that we will be able to see Venus with the naked eye in the morning
sky before superior conjunction.
In September, Mars is rather low (less than about 20 degrees) over
the WSW horizon about an hour after sunset at the beginning of the
month. At this time it is around 6 degrees east of the planet Saturn
and pulling farther away from the ringed planet all month long.
On the 13th Mars moves into the constellation Scorpius, and on the
evening of the 17th, Mars moves into about a 1 degree conjunction
with the star Delta Scorpii, or Dschubba. On the evenings of the
27th and 28th, Mars makes its closest approach to the bright star
Antares, the heart of the Scorpion, and the “Rival of Mars”
– note the stars reddish color! It is similar, although not
identical, to Mars’ color! On the 29th the young crescent
Moon passes about 7 degrees north of Mars, and the Red Planet finishes
the month about 3-4 degrees north of Antares, very low over the
WSW horizon, and setting at about 10:00 p.m.
Jupiter starts September rising a little before 4:30 a.m. in Cancer,
just a little east of the Beehive Cluster M44. On the morning of
the 20th, the waning crescent Moon bypasses Jupiter about 7 degrees
to the south. By month’s end, Jupiter rises at about 3 a.m.
In September, Saturn begins the month about 6 degrees WNW of the
planet Mars in the constellation Libra. Asteroids Vesta and Ceres
are somewhat farther north than Saturn by about 5 and 10 degrees
respectively. While the swifter Mars pulls away from Saturn through
the constellations all month long, Ceres approaches Saturn in the
same time span! On the evening of the 27th the Moon, Saturn, and
Ceres (although not visible to the naked eye) all form a very small
triangle only about 2 degrees to a side, or less! Saturn ends the
month less than a degree away from the tiny Ceres, setting at about
9 p.m. This will probably be the last full month in which we will
be able to spot Saturn in the evening sky until next year.
In early September, Uranus is rising in the evening sky at about
9:15 p.m. in the constellation Pisces. On the 10th of the month,
Uranus is overpowered by the much brighter waning Full Moon, only
3 degrees to the north of the planet. By the end of the month, Uranus
rises at around 7:15 p.m., shortly after the Sun sets.
Neptune is in the constellation Aquarius in the month of September,
already arisen after sunset, and visible with the right optical
aid virtually all night long for the whole month! The nearly Full
Moon makes its closest approach to Neptune for the month on the
evening of the 7th, only about 6 degrees NW of the distant blue
giant. By the end of the month, Neptune is already modestly high
in the SE sky at an hour after sunset.
Ceres is in the constellation
Libra, roughly 10 degrees NNW of Saturn at the beginning of September.
Although Ceres loses ground against the sunset, it overtakes the
much slower planet Saturn all month long. On the evening of the
27th of the month, the young crescent Moon passes close to the largest
asteroid and Saturn in a tight triangle, and at month’s end,
Ceres sets with Saturn at about 9 p.m. Optical aid will be needed
to spot the asteroid / dwarf planet.
In September, Pluto is
in the constellation Sagittarius, slightly before meridian at about
an hour after sunset. On the evenings of the 3rd and 4th the waxing
gibbous Moon bypasses closest to Pluto for the month. At month’s
end, Pluto sets at a little after 11:30 p.m. Optical aid will be
even more desperately needed to view Pluto than was so for Ceres!
A minimum of an 8 or 10 inch aperture telescope and a pristine night
of viewing conditions is required for live viewing.
Showers - http://amsmeteors.org/showers.html
Comets - http://cometography.com/current_comets.html
events - http://www.skyandtelescope.com/observing/highlights