Six night sky events to look up for in Fall 2016
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Monday, September 12, 2016, 9:00 PM - Our nights may be getting cooler as we transition into fall, but as nights get longer and night skies become clearer, the coming season can be one of the best for skywatching. Here are six great events to watch out for in the coming season.
A Season of Supermoons
First on the list for Fall is a trio of events all wrapped into one, as we're in for a season of supermoons.
The Full Moons on October 16, November 14 and December 14 will be the three closest, and thus largest, Full Moons of the year, and the November 14 Moon will be the closest - 2016's Perigee Full Moon, where the Moon reaching fullness and being at its closest point to Earth are separated by only two hours.
The three Super Full Moons of 2016. Credit: NASA's Goddard Scientific Visualization Studio/S. Sutherland
Telling the difference between a "normal" Moon, a perigee Moon and an apogee Moon with the unaided eye is not an easy task, so here's a little guide to help.
2016's apogee Moon (L), a "normal" Moon (C) and 2016's perigee Moon (R), with guidelines to highlight the size difference. Credit: NASA's Goddard Scientific Visualization Studio/S. Sutherland
What, exactly, is a supermoon?
It is a fairly arbitrary reference, and one referencing astrology rather than astronomy, but a supermoon is any Moon - Full or New - that comes at least as close to the Earth as 361,524 kilometres, or according to astrologer Richard Nolle, who coined the term, when the Moon is "within 90% of its closest approach to Earth in a given orbit."
Here's a list of the Moon's distance for the full moons of this season:
• Oct 16 - 358,499 km
• Nov 14 - 356,522 km (closest of 2016)
• Dec 14 - 359,440 km
Read on for why the November 14 Super Full Moon is an extra special one.
October 20-21 - Orionid Meteor Shower
The Orionid meteor shower - the second of the year's two meteor showers that originate from Halley's Comet - peaks on the night of October 20-21.
The Orionid radiant, after midnight, on Oct 21, 2016. Credit: Stellarium/S. Sutherland
The Orionids do not produce as many meteors as the Eta Aquariids in May, only around 20 per hour on average, however since the meteors are fairly bright, they compete well against light pollution and frequently put on a good show for stargazers.
November 14: Closest Perigee Full Moon in over 86 years
The November 14 Full Moon is the closest and largest Full Moon of 2016, making it this year's Perigee Full Moon. However, it also has a larger significance.
At just 356,511 km from Earth when its face is fully illuminated on the night of the 14th, this will be the closest Full Moon seen since 1948, when it came to within 356,462 km of Earth on Jan 26 of that year. Also, no Full Moon after this will come close to matching its distance until November 2034!
Credit: NASA's Goddard Scientific Visualization Studio
Be sure to get out and enjoy it!
November 16-17: Leonid Meteor Shower
In mid-November, the Leonid meteor shower peaks, and even though it typically produces only around 15 or so meteors per hour, the brightness of these meteors, and the occasional extreme outburst of activity from this shower, makes it one to keep an eye on.
The Leonid radiant, in the eastern sky, in the early hours of Nov 17, 2016. Credit: Stellarium/S. Sutherland
Since the Leonid radiant doesn't rise until around midnight, local time, this is definitely a meteor shower for early-risers.
Waiting until the pre-dawn hours gives the radiant enough time to climb higher in the sky, and thus give a better chance at seeing the most from this shower's peak.
December 13-14: Rock Comet Meteor Shower
One of the three strongest meteor showers of the year, the Geminids peak on the night of December 13-14, and despite coinciding with the Full Moon, there is some promise that this shower will still put on a great show.
The location of the Geminid radiant on the evening of Dec 13, 2016, in the constellation Gemini. Credit: Stellarium/S. Sutherland
The Geminid radiant rises just after sunset and remains in the sky all night long on the 13th. Additionally, unlike some meteor shower radiants that arch through the sky closer to the horizon, the Geminid radiant climbs high, reaching the ideal "zenith" around midnight. This positioning of the radiant tends to give the greatest number of meteors, and the Geminids are known for delivering up to 120 meteors per hour during this time.
The only down-side of this particular Geminid meteor shower peak is the timing with the Full Moon. Any source of extra light in the sky has the effect of washing out the dimmest meteors of any shower, however the Geminids do have an advantage. Since the meteor shower's source - 3200 Phaethon - is a so-called "rock comet," the majority of the debris Earth sweeps up during this shower is gravel, rather than ice. So, the meteors tend to be quite bright.
Thus, even with the Full Moon, as long as a viewer can remove any other source of light - such as light pollution from cities, highways and the like - this meteor shower is still worth getting out for!