How to watch tonight's Orionid meteor shower from anywhere
Thursday, October 20, 2016, 5:47 PM - Bright Orionid meteors are set to light up the sky tonight, as Earth passes through debris left behind by Halley's Comet. Will the Moon spoil the view? Here's how to watch from anywhere! It's the Night Sky this Week!
October 20-21 - Orionid Meteor Shower
On the night of Thursday, October 20, to Friday, October 21, the sky is expected to light up with streaks of light, a display put on courtesy of the Orionid meteor shower.
Although the Orionids - the second of two meteor showers during the year that originate from Halley's Comet - go on for over a month, from early October to early November, the shower typically reaches its peak somewhere around October 20-24.
This year, the peak is expected on the night of October 20-21, as Earth passes through the greatest concentration of comet debris in Halley's trail.
Wait for the constellation of Orion - The Hunter - to rise that night to find the meteor shower's radiant, which is the point in the sky from which all the meteors appear to radiate out.
The Orionid radiant, in the early hours of Oct 21, 2016. Credit: Stellarium/S. Sutherland
The Orionids are not one of the strongest meteor showers of the year. Typically, under ideal conditions, it only produces about 20 meteor streaks per hour. What are ideal conditions? Zero light pollution, including having no Moon in the sky, thus guaranteeing the best view, and with the radiant directly overhead. Compared to meteor showers like the Perseids and the Geminids, which can produce over 100 meteors per hour, on average, the Orionids are fairly weak.
Every once in awhile, however, the Orionids go through an outburst, due to Earth passing through a particularly dense part of Halley's debris stream. This happened during the 2007 shower, when the meteor rate jumped up to 70 per hour!
This year is not expected to be an outburst, and the waning gibbous Moon will be in the sky that night, tracking along right next to the radiant from the time they both rise (about 10:30 p.m. local time) until dawn. So, unfortunately, the Moon's light will end up washing out many of the meteors, making this particular shower difficult to see.
One advantage the Orionids have, however, is that the bits of comet debris are travelling fairly quickly as they plunge into Earth's atmosphere. This produces two effects: 1) the meteors tend to be on the brighter side, on average, and 2) they can sometimes leave behind an effect known as a persistent train.
When a meteoroid particle enters the atmosphere, the bright streak of light it produces (the meteor) is due to the atmospheric gases in its path being suddenly compressed and heated. The meteor goes out when either the meteoroid slows down enough that it is no longer compressing the air to the point of glowing hot, or the heating actually vapourizes the meteoroid, leaving nothing behind.
A persistent train forms when a meteoroid is travelling so quickly that the sudden heating of the air in its path strips away electrons from the air molecules, ionizing them. These air molecules linger along the path and emit light when they pick up a replacement electron, and this shows up to us, on the ground, as a wispy, dimly-glowing ribbon in the sky. Since it takes some time for all of the ionized molecules to pick up electrons, and the air molecules are just floating along with the other air molecules in the area, being blown around by the wind, these trains have been known to persist for up to half an hour!
Watch Below: YouTube user Cory Poole spotted this persistent train during the 2015 Orionid meteor shower
How to watch
The chances of seeing a significant number of meteors, with or without persistent trains, are low for this shower, what with the Moon in the sky at the same time, however, if you're up for the challenge, be sure to get as far away from city lights as possible, to maximize your potential, and let your eyes adjust to the dark for at least 30-40 minutes.
The shower originates from the point near the constellation Orion, which rises in the east around 10:30 p.m., local time, and then traces a path towards the south, climbing higher in the sky with each passing hour, until dawn. The meteors themselves, however, can actually appear anywhere in the sky as they radiate out from that point. Thus, the best way to observe is probably to keep your back to The Hunter throughout the night. So, face westward to start and look upwards, and slowly turn towards the north as the night progresses.
That will keep the direct light from the Moon out of your eyes, while giving you the widest field of view of the night sky.
Of course, the weather will be key to viewing as well, as any significant cloud cover, or even just water vapour content of the upper atmosphere, can spoil the chances of seeing any meteors at all.
Below is the cloud cover forecast for Thursday night into Friday morning.
The whiter the clouds, in the above animation, the thicker the sky-obscuring clouds will be.
Those regions from southwestern Ontario through to Atlantic Canada appear to be out of luck for this meteor shower, as weather systems have them socked under thick cloud layers. Saskatchewan is also under cloud through the night, however as it advances from the western to eastern sides of the province, it would seem to afford at least some clear skies throughout the night. Those areas between southwestern Ontario and eastern Manitoba are shown clear in the animation, however there is some low-level cloud indicated in the forecast. A closer looks shows that it should be broken enough to afford some view of the sky between them, however check your local forecast to be sure.
Trapped under foul weather? Watch it from anywhere!
If your sky conditions offer no chance to see the meteor shower, there's still an opportunity, provided by the Slooh Community Observatory.
According to Slooh:
On Thursday, October 20th, at 5:00 PM PDT | 8:00 PM EDT | 00:00UTC, Slooh will host a special broadcast of the Orionid Meteor Shower starring a dazzling display of lights raining across the night's sky. The five-hour livestream will be anchored by live feeds at Slooh’s flagship observatory at the Institute of Astrophysics of the Canary Islands, as well as Slooh’s global feed partners in the United Kingdom and the US.
In addition to the live feeds, Slooh’s five-hour broadcast, hosted by Slooh’s Chief Astronomical Officer, Paul Cox, will give viewers everything they need to know to enjoy the shower, including information on the best ways to watch, where to look, and what they should bring along with them on their meteor spotting journey. Slooh Astronomer, Eric Edelman, will stop by to explain the basics of how meteor showers come about, while Slooh Astronomer, Bob Berman, helps viewers get to know the Orionids and their connection to the famous Halley’s Comet.
You can go to Slooh.com to join and watch this live broadcast, snap and share your own photos during the event, chat with audience members and interact with the hosts, and personally control Slooh’s telescopes.