The Northern Hemisphere’s full Harvest Moon has passed. Now the moon is in a waning gibbous phase, which means it rises in the east later and later each evening. Look east before going to bed tonight to catch the moon over the eastern horizon. Then look in the west after sunrise tomorrow, or in the next few mornings, to see the daytime moon over your western horizon.
At the southeast corner of the house-shaped constellation Cepheus the King, there is an intriguing variable star called Delta Cephei. With clocklike precison, this rather faint star doubles in brightness and fades again every 5.36 days. You can see it change over a period of days. The entire cycle is visible to the eye alone in a dark-enough sky. This star and others like it have secured a place as important standard candles for establishing the scale of the galaxy and universe.
The Great Square of Pegasus consists of four stars of nearly equal brightness that make a large square pattern. It is best seen from September to March.
Like any full moon, the full Harvest Moon rises around sunset and shines all night long. So what’s special about the Harvest Moon? On the average, the moon rises 50 minutes later every night. Around the time of the Harvest Moon, at mid-northern latitudes, moon rises only about 35 to 40 minutes later for several evenings in a row.
Expect higher-than-usual tides in the days following Monday’s supermoon. Ocean tides result from the gravitational interaction and the ever-changing geometry between the sun, moon and Earth. These recommended tide almanacs are based upon the relatively straightforward astronomical influences on the tides, not the hard-to-predict meteorological factors, such as barometric pressure and wind.
The 2014 September equinox comes on September 23, at 2:29 Universal Time. Although the equinox happens at the same moment worldwide, the clock times will vary by time zone. So in the U.S. this equinox comes on September 22 at 10:29 p.m. EDT, 9:29 p.m. CDT, 8:29 p.m. MDT or 7:29 p.m. PDT.
Simply stated, the Harvest Moon is the full moon that falls the closest to autumnal equinox. So the full moon that comes tonight – on September 8-9, 2014 – is the Northern Hemisphere’s Harvest Moon. Watch for it to ascend over the eastern horizon tonight as the sun sets in the west.
Don’t expect to see the planet Neptune tonight (September 7, 2014), even though tonight’s waxing gibbous moon shines fairly close to this world on the sky’s dome. Even on the darkest of moonless nights, you need an optical aid to see Neptune, the eighth planet outward from the sun. But, although you won’t see Neptune tonight, you can use tonight’s moon to get a feel for the whereabouts of Neptune and the zodiacal constellation Aquarius in the starry heavens. Aquarius lies to the north of the bright star Fomalhaut, which will be visible tonight – despite the moonlit glare.
It’s an early Harvest Moon this year for the Northern Hemisphere. Look for the Harvest Moon to shine on the night of September 8-9, 2014. And it’s not just any Harvest Moon. It’s also a supermoon. Follow the links inside to learn more.