Sky Data
Saturday September first, sunrise is at 6:23 a.m. Eastern Daylight Time. That evening the Sun, located in the constellation Leo, sets at 7:27 p.m.
Saturday September 15 sunrise is at 6:37 a.m. and sunset occurs that day at 7:04 p.m.
The last day of this month Sunday the 30th, the Sun is in Virgo, rising at 6:52 a.m. and setting at 6:39 that evening. During September the intervals of time the Sun is above the horizon each day decrease by one hour and 17 minutes. The altitude of the Sun at solar noon, its maximum daily elevation, descends during September from 57 degrees of arc on the first to 46 degrees on the 30th.
Average overnight temperatures recorded in Central Park during September drop from 66 degrees Fahrenheit on the first to 55 degrees on the last day of this month.
Principal Phases of the Moon are:
| Last Quarter | September 8 |
| New Moon | September 15 |
| First Quarter | September 22 |
| Full Moon | September 29 |
Sky Notes
Whenever I see the Moon, thoughts of Apollo astronauts are nearly always in my mind. With the passing of Neil Armstrong memories of his leap onto the lunar surface in 1969 seem as fresh as the images were on that long ago July night. Consummate skill and courage of Armstrong and his colleagues, backed by the knowledge, foresight, and commitment of fellow citizens will be remembered as long as civilization endures.
As he made those distant footprints Neil Armstrong was watched by millions who could clearly remember 1903 when they read news of Orville Wright’s first flight. For 17 years between Armstrong’s birth and Orville’s passing, these immortal pioneers, as well as Charles Lindbergh conqueror of Atlantic airspace, were alive at the same time. We wonder if the first human to set foot on Mars has yet been born. Extrapolation of this timeline might help us imagine the answer.
On Tuesday evening September 25th, I’ll be at the Hayden Planetarium Space Theater previewing events in autumn’s sky as part of the Astronomy Live! program. We’ll also be looking at some regions where researchers are making some remarkable discoveries far beyond the Milky Way Galaxy. Here’s a link for more information about the evening.
Sky Cast
The morning of Saturday September 1, Venus rises at 2:42 a.m. in the constellation Gemini, Mercury rises at 5:36 in Leo, and Neptune in Aquarius sets at 5:49, just 34 minutes before sunrise. That evening the waning gibbous Moon rises at 7:42 in Pisces, south of the Great Square of Pegasus. Uranus, at the border between Cetus and Pisces, rises at 8:27 p.m. Saturn is in Virgo setting at 9:26, Mars also in Virgo sets at 9:37, and Jupiter rises between the horns of Taurus at 11:39 p.m.
Friday evening September 7, the Last Quarter Moon rises three minutes before Midnight. It is in Taurus near Jupiter, and just before sunrise the Moon is one degree of arc from the big planet.
The early morning of September 12th, after about four a.m., the narrow crescent Moon may be seen five degrees from Venus above the eastern horizon in the constellation of the Crab.
During evening twilight Monday September 17th the thin waxing crescent Moon is near Saturn and first magnitude star Spica in Virgo.
The Northern Hemisphere’s autumn season begins at 10:49 a.m. Saturday September 22nd. At that time the Sun is directly above the equator at a point in the Atlantic 115 miles northeast of the Brazilian coast.
The First Quarter lunar phase is also on the 22nd. That night the Moon is in Sagittarius, near the direction to the center of the Milky Way Galaxy.
The Harvest Moon occurs Saturday September 29th. This is the Full Moon nearest the date of the Autumn Equinox. At this time of the year intervals between successive moonrises on several evenings just after the night of Full Moon are less than at other times of the year. This provides nearly continuous bright moonlight after sunset for several nights as farmers bring in crops. The Harvest Moon is in Aquarius, south of the head of Pegasus the mythological Flying Horse.
Sunday September 30, Venus rises at 3:25 a.m. in the constellation Leo, and Neptune in Aquarius sets shortly thereafter at 3:52. That evening Uranus, just inside the constellation boundary of Cetus, sets at 6:52 p.m., Mercury is then in the evening sky and sets at 7:11 in Virgo, near Spica, Saturn is also in Virgo setting at 7:39, Mars has moved into Libra setting at 8:38, and Jupiter rises between the horns of Taurus at 9:51 p.m.
Sky Lore
With the arrival of September our evening sky’s center stage features a number of brilliant stars in constellations along the Band of the Milky Way. When civil twilight fades on the first of this month stars of the Summer Triangle: Vega, Altair, and Deneb are at high altitudes by the celestial meridian. Near the middle of the southern horizon Antares and fine asterisms of the Scorpion and the Teapot of Sagittarius are also visible. Although these two constellations rapidly disappear from view in early October, stars further north such as those forming the Summer Triangle remain in our sky until late December.
Above the eastern horizon during September we begin to notice the Great Square of Pegasus. Although its stars are only of second magnitude, the pattern’s symmetry catches our eyes when seen in dark skies. It then serves well as a marker for exploring adjacent constellations throughout autumn.