What’s up for September 2015? A total eclipse of the harvest moon!
On the evening of Sunday, Sept. 27, observers in North and South America will see a long total lunar eclipse – lasting 72 minutes. This eclipse is also visible in Europe and Africa.
It’s the night of the harvest moon – the full moon closest to the September equinox.
Equinox is derived from the Latin for “equal night.” So day and night on the 27th will be of roughly equal length, and the sun will rise exactly in the east and set exactly in the west.
The September full moon is sometimes called the Supermoon – a term coined just a few years ago.
A “supermoon” is a new or full moon which occurs when the Moon is at or near its closest approach to Earth in a given orbit.
Four to six supermoons occur every year on average, so they’re not unusual. “Supermoon” is just a useful word for drawing attention to news stories.
At only about seven per cent larger, you won’t really see the difference between this full moon and any other one with your eyes. The moon is 221,457 miles (356,877 km) from Earth this month, compared to the average distance of 238,855 miles (386,400 km).
The partial lunar eclipse begins at 6:07 p.m. PST. It will last a little more than an hour, and observers can watch as, crater by crater, the moon is engulfed in Earth’s shadow. Oak Bay viewers take note: when the eclipse begins, the moon won’t have risen yet for you.
The total eclipse begins at 7:11 p.m. and lasts more than an hour, ending at 8:23 p.m. The moon’s reddish colour you’ll see is caused by sunlight refracted through Earth’s atmosphere on its way to light the moon’s surface.
This month the moon skims Earth’s shadow, just as it did in the April lunar eclipse.
In April the north pole appeared a bit brighter during totality. This time, the southern pole will appear a bit brighter, a bit like a partial eclipse.
Then, it’s the whole show in reverse order, ending at 9:27 p.m. here on the West Coast.
When you’re not eclipse-watching, catch Mercury, Saturn, Neptune and Pluto in the evening sky, Uranus and Neptune at midnight and Venus, Mars and Jupiter in the morning sky.
Rosetta’s target, Comet 67P (Churyumov-Gerasimenko), is getting bright enough this month for experienced astronomers to pick it out in a dark sky. The Comet is the size of Mount Baker. It reached its closest to the Sun last month and is now heading back out in its eight-year orbit.
Remember the lander Philae is still on its surface and the Rosetta Orbiter (the mother pod) is also orbiting the Comet taking amazing photos and doing particle analysis as it passes through the huge geysers being “squirted” out.
Very interesting results are being published every month. In particular I’m interested to see if “life” is found along with the complex molecules of life already discovered last month. The amazing MIDAS “microscope” can “see” down even below the bacteria level.
On Thursday, Sept. 10, you may be able to spot it through a telescope above the moon and Venus over Mount Baker.
On the mornings of Wednesday, Sept. 16 and Thursday, Sept. 17, the comet is close to the easy-to-see Beehive Cluster in the constellation Cancer -- high in the sky just before dawn.
Finally, you can still get a great view of our Milky Way Galaxy spanning the sky from southwest (Metchosin) to northeast (Vancouver) -- if you can escape to a dark location such as Cattle Point Star Park.
Summary from “What’s Up in September 2015” by NASA announcer and astronomer Jane Houston Jones with permission for localization to Cattle Point Urban Star Park and the Oak Bay News. Bill Smith and the RASCals are volunteers at Cattle Point Dark Sky Urban Star Park.