Two great astronomical events still to watch in Spring 2016
Friday, April 22, 2016, 3:32 PM - There's been plenty going on in our night skies so far, but there are still two more major astronomical events happening this season (as well as an extra one thrown in for those who like a challenge).
May 5 - Eta Aquarid meteor shower
Every year, Earth makes two passes through the path of debris left behind as famous Comet Halley orbits the Sun, and the first of these passes is coming up this spring.
For several nights centred around the 5th of May, as we encounter this stream of ice and dust, the Eta Aquarid meteor shower will light up our night skies.
The radiant of the eta Aquarid meteor shower, on May 5, at 4:15 a.m. Credit: Stellarium/S. Sutherland
Although astronomers aren't expecting a particularly good show this year, due to exactly which part of the debris stream we're passing through, it could still give us around 40 meteors per hour under ideal conditions.
Even better, this year's Eta Aquarids are happening during a new moon - the absolute best time to watch a meteor shower!
The meteor shower's radiant - the point in the sky where the meteors appear to originate from - rises above the eastern horizon at around 3 a.m. local time. The meteors should become visible just before that time until when the sun starts to rise a few hours later. The best place to look to see the meteors, though, is straight up (rather than off to the horizon), since that will afford the best view of the entire night sky.
May 9 - Transit of Mercury
This one comes with a warning to never look directly at the Sun, for any length of time, without the proper eye protection or the proper filter for your telescope.
On the morning of May 9, anyone with the proper equipment - Mylar eclipse glasses, a pinhole projector or a telescope with a proper solar filter - will be able to witness an uncommon sight.
Starting at 6:12 a.m. EST and ending at 1:42 p.m. EST on the 9th, the positions of Earth and Mercury will be lining up just right to allow us to watch Mercury pass directly between us and the Sun. This will show up as a tiny dark dot tracking across the Sun's bright face.
To see it, you can secure some Mylar "eclipse glasses" to protect your eyes, although it may be too small to see that way. There are special sun filters you can buy for your telescope, but if you go this route, be sure to get the one that caps the end of the 'scope, rather than the one that screws into the eyepiece (letting unfiltered sunlight be focused through a telescope can damage it). If you don't own a telescope and can't find any Mylar glasses, check the local observatories and astronomy clubs (the Royal Astronomical Society of Canada is an excellent resource) to see if they are hosting a viewing event.
The safest (and quite possibly the best) way to see it, though, is to check out the views from NASA's Solar Dynamics Observatory (SDO) and the NASA/ESA Solar and Heliospheric Observatory (SOHO). Both of these spacecraft have their cameras trained on the Sun 24/7, and we'll be able to watch it happen real time from their vantage in space!
Credit: Xavier M. Jubier/xjubier.free.fr
Still up for a challenge?
When it comes to skywatching and stargazing some of these astronomical events are better than others, simply based on the particulars of when they're occurring. The ones above are the best for this season, but not necessarily all of them. Here's another event coming up, which might be a bit more of challenge to see.
April 22/23 - Lyrid meteor shower
On the night of Friday, April 22 to Saturday, April 23, stargazers may be able to catch a a few meteors during the peak of the Lyrid meteor shower.
This meteor shower isn't one of the strongest of the year, as it only delivers about 15-20 meteors per hour under ideal conditions, but the meteors tend to be bright. Some even produce fireballs in the night sky.
Another complication to watching this particular meteor shower is visible off to the right in the above image - the bright full moon. With this source of "competition" in the sky all night long, it will be difficult to see the Lyrids this year, as the Moon's light will spoil a viewer's night vision. It is still possible to see the few brightest meteors though. Be sure to get far away from any other sources of light pollution (ie: cities), to give yourself the best chance.
The position of the Lyrid meteor shower radiant, in the East, at roughly midnight, April 22/23. Credit: Stellarium/S. Sutherland
What have we already seen so far?
March 8 - Close asteroid flyby, but still how close?
The "cloud" of dots extending outward from the Earth show the numerous possible trajectories of asteroid 2013 TX68 as it flies by. The image now depicts the revised distances to this asteroid. Credit: NASA/JPL-Caltech/S. Sutherland
The flyby of this roughly 30-metre-wide asteroid wasn't visible from the ground, except from large telescopes and only if its position was exactly known.
The timing of this flyby was a little uncertain as well. Originally expected around March 5, NASA updated the asteroid's closest approach to Earth to March 8.
Much of the uncertainty involved in this asteroid's orbit was due to the limited number of initial observations, however it was partly due to the object's approach to Earth, which was from the direction of the Sun.
Based on what they already knew about the asteroid, NASA astronomers were already certain that 2013 TX68 posed no threat to Earth, either in March 2016 or anytime in the future, however as of yet, no observations of the asteroid have been reported from the flyby.
March 8/9 - Total Solar Eclipse across the Pacific
On March 8 and 9, depending on where you live in the world, the Moon was crossing the face of the Sun, producing a total solar eclipse.
The Moon's shadow was focused onto a thin patch of the Earth, starting over Southeast Asia on the morning of March 9, and tracking across the Pacific Ocean over a period of about three and a half hours. Towards the end of this journey, the shadow briefly performed a bit of "time travel" as it crossed the international date line into the late afternoon of March 8, to be visible as a partial solar eclipse from Hawaii to Alaska and western half of Yukon territory.
While this particular eclipse wasn't directly visible for anyone who wasn't in the far northwestern corner of Canada, it was featured in images and livestream feeds on the web.
March 14/15 - Double shadow on Jupiter
If you remember when the Hubble Space Telescope captured a rare triple-shadow crossing the face of Jupiter in January 2015, this one was something to definitely check out.
On the night of March 14-15, the shadows of Io and Europa - the two innermost of Jupiter's Galilean Moons - tracked across the tops of this giant planet's cloud layers.
Simulated view of the Io-Europa double-shadow transit on March 14/15, 2016. Credit: Stellarium/S. Sutherland
This particular event started at 9:45 p.m. EST, March 14, as Europa cast its shadow onto Jupiter first, with Io's shadow joining it at 10:19 p.m. EST. Both shadows were visible until 12:35 a.m. on the 15th, when Europa's shadow slipped out of view, followed just a few minutes later by Io's.
Compared to last year's triple-shadow, these double-shadow transits aren't very rare. Io and Europa team up for over dozen of them this year (in Feb, March and April), there's a half-dozen Io-Ganymede pairings (split between March and August), two Io-Callisto transits (one in April and one in May), and four Ganymede-Europa pairs as well (in October and November).
A telescope was needed to see these events, but a quick search for images on the web is bound to turn something up.
March 22 - A newly discovered comet swings by for a visit
Position of Comet P/2016 BA14 (PanSTARRS) on March 22, 2016. Credit: Celestia/S. Sutherland
Although originally thought to be an asteroid when it was first discovered, astronomers quickly found a few oddities about this object which stood out to them. It and eventually resulted in it being reclassified as a comet. out that "2016 BA14" was really a comet, and not just any comet, but very likely a fragment of comet 252P/LINEAR 12.
March 23 - Penumbral lunar eclipse
Following the March 8/9 solar eclipse, there was a lunar eclipse. It was visible from roughly the same part of the world, and much of Canada was able to catch at least part of it, but there was a down side. Unlike the amazing "blood moon" lunar eclipses that we've had over the past two years, for this one, the Moon only passed through part of the Earth's diffuse outer shadow (the penumbra). This meant that, even if you were in the right part of the world to see the entire event, it was only be barely noticeable, as a slight dimming of the Moon's brightness.
Still, part of the fun of astronomy, sometimes, is taking on the challenge of trying to see these kinds of events.
Watch Below: What space in 2016 has in store for us (and for science)