Here’s a quick look at what’s going on in the sky during the month of September 2015:
All events are Eastern Daylight Time and as seen from the Northern Hemisphere:
September 3 — Heliacal setting* of Spica
September 4-5 — For those living in New England states and the Canadian Maritimes, you can view the Moon occult the star Aldebaran. An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. So you can actually see the Moon cover the star! Times to watch: New England from approx. 11:45 pm to 12:45 a.m., and Canada, watch from approx. Midnight on 9/5 to 1 a.m.
September 4 – Mercury at its great eastern elongation. When an inferior planet is visible after sunset, it is near its greatest eastern elongation.
September 5 — Last Quarter Moon at 5:54 a.m. In this phase, the Moon appears as a half Moon. One-half of the Moon is illuminated by direct sunlight while the illuminated part is decreasing, heading toward the New Moon (invisible) phase.
September 9 – Before sunrise on the mornings of September 9th and 10th, look to the east to see the tiny waning crescent Moon and the planets Venus and Mars. Venus will be the brightest object, and will be right below the Moon. Mars will be fainter, and off to the left of them. On the 10th, the Moon will be below Venus, and will form a “wink” with Mars.
September 10 – Look to the east before dawn to see the zodiacal light, also known as the “false dawn.” Visible for the next 2 weeks. Also look for the tiny waning crescent Moon team up with Venus in the predawn sky. If the sky is dark enough, look for Mars to the left of the pair (you may need binoculars).
September 11 – Look to the east before dawn for the tiny waning crescent Moon and the star Regulus forming a “wink.” At this time, Jupiter is very low on the horizon but you might be able to catch it!
September 12 – Heliacal rise** of Jupiter. At dawn, you may also see the almost-invisible waning crescent Moon below Jupiter, but you’ll need binoculars.
September 13 — New Moon at 2:41 a.m. At this stage, the Moon is not illuminated by direct sunlight and is completely invisible to the naked eye.
September 15 — If you’re in mid-Northern Latitudes it may be a challenge but grab your binoculars and look for the tiny waxing crescent Moon with the star Spica low in the western horizon right after sunset. Higher in the sky as night falls, everyone will be able to see Saturn and the star Antares! Look southwest evening sky.
September 18 — Look to the southwest after dusk to see the waxing crescent Moon (at 27% full) and Saturn very close together like a ‘wink.’
September 21 —First Quarter Moon, 4:59 a.m. In this phase, the Moon looks like a half-Moon — one-half of the Moon is illuminated by direct sunlight while the illuminated part is increasing, on its way to full.
September 23 — Autumnal Equinox, 4:21 a.m. The Sun crosses the Equator and darkness begins to win out over daylight.
September 27 — Full Harvest Moon, 10:50 p.m. At this phase the visible Moon is fully illuminated by direct sunlight.The Harvest full Moon is the full Moon nearest the autumnal equinox.
The Moon is also at perigee (its closest point to Earth) at 10:00 p.m., when the Moon’s distance is only 221,870 miles from Earth (The absolute closest that the Moon can come is 221,400 miles from Earth). This makes this full Moon an official supermoon. A full supermoon can look up to 14% larger and be up to 30% brighter than a normal full Moon.
September 27-28 – And there’s more! There will also be a total lunar eclipse! A lunar eclipse is when the Moon passes into the Earth’s shadow. Because the Moon only shines by reflected sunlight, the Moon will gradually darken as it enters the shadow. The total lunar eclipse is visible from most of North America (except Alaska and northernmost Canada) after sunset on September 27.
Timing of Total Lunar Eclipse:
8:11 p.m. – Moon enters penumbra
9:07 p.m. – Moon enters umbra
10:11 p.m. – Total eclipse begins
10:48 p.m. – Mid-totality
11:23 p.m. – Total eclipse ends
12:27 a.m. (9/28) – Moon leaves umbra
1:22 a.m. (9/28) – Moon leaves penumbra
* Heliacal Setting: When a star is overtaken by the Sun and is lost in in its rays.
** Heliacal Rising: The rising of a celestial object at the same time, or just before, the Sun, or its first visible rising after a period of invisibility due to conjunction with the Sun.