The Harvest Moon Comes to Linger, Evening Planets, and Oodles of Observing Opportunities!

The Moon and Planets

The Moon spends this week growing fuller until Friday afternoon, when the full moon of September, traditionally called the Harvest Moon, occurs. The Harvest Moon always shines within or near the faint stars of Pisces the Fishes. Since full moons always sit opposite the sun, they rise at sunset and set at sunrise. At the Autumnal Equinox, occurring annually around September 22nd, the evening ecliptic meets the horizon at a shallow angle. For this reason, from evening to evening, the Harvest Moon’s orbit carries it more sideways than down. For several evenings in a row, the Moon will appear nearly full and rise at nearly the same time, making it more likely you’ll notice it on your daily routine. The lingering moonlight also helped extend the farmers’ harvesting workdays.

The moon normally rises about an hour later every evening, but the September Harvest Moon rises only a bit later each night, due to the shallow tilt of the ecliptic. Here the moon is shown for 8:35 pm local time on September 15 (upper right), 16, and 17 (lower left), 2016) via Star Walk 2 app.

At this full moon, observers in Europe, Asia, Australia, Africa, and the western Pacific will observe a penumbral lunar eclipse, where the moon passes through earth’s shadow, but misses the deepest part, so only a minor darkening of the moon is observed. The greatest amount of eclipse occurs on September 16 at 18:55 Universal Time (or GMT).

Have you been noticing the prominent triangle formed by two planets and a star in the southwestern sky every evening? The highest object is yellowish Saturn. Brighter, reddish Mars sits well off to the east (left). And the twinkling star Antares, the brightest star in Scorpius the Scorpion, is below and on the right. The trio sets by about 10:30 pm local time. Keep your eye on Mars as every night it shifts a little to the left, towards the Milky Way and the Teapot of Sagittarius the Archer.

Three naked eye planets are collected in the southwestern sky after sunset. Venus sets first, following the Sun down, while red Mars and Saturn, above the bright red star Antares, linger into late evening via Star Walk 2 app.

Venus continues as the very bright object low in the western sky after sunset. It sets about 8:30 pm this week. Uranus and Neptune are in the eastern evening sky. Uranus, between the fishes of Pisces, rises about 8:30 pm local time, while Neptune, in Aquarius the Water-Bearer is already up at dusk. Due to their extreme distance, they change location only a little from week to week. I’ll post a sky chart here.

Uranus and Neptune, sitting among the faint stars of Pisces and Aquarius respectively, are well placed for nighttime viewing in September, 2016. Stellarium software simulation via Star Walk 2 app.

Pegasus and Andromeda

If you missed last week’s extensive tour of Pegasus and Andromeda, It’s here.


Iridium flares are glints of sunlight off of the flat reflecting sides of one of the satellites that comprise the Iridium pager and sat-phone network. The flares occur before dawn and after dusk, when the satellite passing overhead is still illuminated by the Sun, which is below the horizon for observers on the ground. The duration and brightness depend on the angles between the observer, the satellite, and the Sun. For even more info about Iridium Flares and the space station, see an article that I wrote here. Using an accurate clock, go outside a few minutes ahead and look in the direction indicated. You should first see the dim Iridium satellite moving quickly across the sky, and then it will rapidly brighten for 3 to 8 seconds, and fade out. Truly spectacular! The more negative the Magnitude number, the brighter. The larger the Alt. number, the higher up it is! (The horizon is 0°, and 90° is straight up, so 55° is a bit higher than halfway between the horizon and zenith.) These data are adapted from To get your own schedule, enter your location in their website.

Keep looking up to enjoy the sky! I love getting questions so, if you have any, send me a note.

Stargazing News for this week (from September 11th) by Chris Vaughan.

One clap, two clap, three clap, forty?

By clapping more or less, you can signal to us which stories really stand out.