Top 10 celestial events of 2017 to eclipse them all
January 8, 2017
2017 is really a one-event year, for much of the U.S. All other celestial events pale into insignificance compared to this one.
This is the year of the Great Solar Eclipse. The BIG one. The one that U.S. astronomy enthusiasts have been waiting for since 1979.
On Aug. 21, the shadow of the moon will sweep across the 48 contiguous states, from coast to coast, putting millions of people within a short drive of one of nature's most spectacular celestial events — a total eclipse of the sun.
Just the same, I have sifted through all of the 2017 celestial events and selected the 10 that I am the most excited about. These are my "Top 10 Celestial Events" for 2017, in chronological order.
Most of my selections can be watched and enjoyed with the unaided eye, but a few will require binoculars or a small telescope to enhance the view and, in the case of the solar eclipse, a safe solar filter for your eyes.
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For updates on these and other celestial events this year, keep an eye on my monthly "Celestial News" column and the NASA sponsored website SpaceWeather.
You are also invited to come and see my special eclipse program, "Shadows in Space," which will be held at 7 p.m. Friday, Feb. 3 in the Albright Family Auditorium on the Colorado Mountain College Steamboat campus. I'll share some of my personal total solar eclipse experiences and tell you all about the Big One coming up.
Jan. 12: See the Evening Star at elongation
An inferior planet, such as Mercury or Venus, spends much of its time too close to the sun for us to see well from Earth. They are the only planets that can pass both in front of the sun and behind the sun, as seen from Earth.
In between those passes by the sun, an inferior planet will swing out from one side of the sun to the other during its greatest elongations. It is during these greatest elongations when an inferior planet is best seen.
On Thursday, Venus will reach its greatest elongation 47 degrees on the eastern side of the sun and will dominate the western sky after sunset for nearly four hours before setting. Glowing as our "Evening Star," Venus will outshine every other star-like object in the sky.
At elongation, Venus will look like a tiny, half-lit moon in any small telescope. In the days that follow, Venus will start slipping closer to the sun again until it passes between the Earth and sun on March 25, an event called inferior conjunction.
After that, Venus will swing out on the other side of the sun to shine as our "Morning Star" through the spring, summer and fall.
Jan. 31: The moon, Venus, Mars meet at dusk
Close groupings of the moon and planets in earthly skies have no cosmic significance whatsoever. After all, their apparent closeness is only an illusion. The celestial bodies can be millions of miles apart and, yet, by cosmic coincidence, they lie along the same line of sight as viewed from Earth.
Because the five naked eye planets are among the brightest objects in our night sky, gatherings are often spectacular. That's why this tight grouping of three worlds in our early evening sky Jan. 31 makes my top 10 list this year.
When deep dusk arrives about 6 p.m. that night, the moon will be a slender crescent in the southwestern sky, only four days past new. Six degrees to the right of the moon, dazzling Venus will glow and 3 degrees above the moon, ruddy Mars will shine. You'll be able to cover all three worlds with your thumb held at arm's length.
Catch them early in the evening, because by 9 p.m., they will all have set in the west. By my judgment, this is the best planet-moon conjunction of 2017.
March 4: Watch the moon eclipse a bright star
As the moon orbits Earth, it occasionally will pass in front of a bright star and hide it, an event called an occultation. There are only four bright stars along the moon's path that can be occulted from time to time — Alpha Leonis (Regulus), Alpha Virginis (Spica), Alpha Scorpii (Antares) and Alpha Tauri (Aldebaran).
Early on the evening of March 4, the first quarter moon will perform a prime time occultation of Aldebaran for folks living in the western U.S. The dark, eastern edge of the moon will creep up to Aldebaran and occult it around 8:35 p.m.
Because the moon has no atmosphere to dim the star's light and the star itself is so distant that it appears to us as a mere pinpoint of bright light, Aldebaran will wink out in a split second. One moment it will be there and the next moment — poof — it will be gone.
The moon will cover Aldebaran for about 50 minutes before it pops back into view about 9:25 p.m. Because Aldebaran will reappear on the bright edge of the moon, the reappearance probably will be a little tougher to see with the unaided eye than the disappearance. In any case, binoculars or a telescope of any size will provide an excellent magnified view of the event.
April 1: Catch elusive Mercury at dusk
One of nature's toughest challenges is catching a glimpse of our solar system's innermost planet, Mercury.
Even at its greatest possible elongation, it can only manage to extend 28 degrees away from the sun. That means Mercury follows the setting sun by only two hours, at most.
To maximize your chances, you want to catch it near greatest elongation in the evening sky in the spring or the morning sky in the fall. If the moon or another bright planet is nearby, you can use it as a guidepost.
The best evening opportunity to catch Mercury this year occurs within a few days of its greatest elongation, 19 degrees east of the setting sun, on April 1. To pinpoint the little planet, try looking low in the western sky between 7 and 7:30 p.m. March 29.
The slender crescent noon will be sitting about one-fist width at arm's length to the upper left of Mercury. The planet Mars will be about the same distance above the moon, but Mercury will appear brighter.
With each successive night, the moon will pull farther and farther away from Mercury, leaving the planet all alone in that big western sky. After greatest elongation, on April 1, Mercury will zoom back toward the setting sun, passing between Earth and sun during inferior conjunction April 19.
Is 2017 the year that you get to check "See the planet Mercury" off of your celestial to-do list?
April 7: See Jupiter at its best
Jupiter is king when it comes to ruling the midnight sky, shining brighter than any other object, except the moon.
Jupiter is the first bright outer planet to reach opposition this year. It will be at its closest point to Earth and brightest in our sky April 7. Jupiter will rise in the east just as the sun goes down in the west and will gleam brilliantly from high overhead in our midnight sky, with the constellation Virgo in the background.
On the night of opposition, Jupiter will be a mere stone's throw from Earth — about 4.45 astronomical units or about 414 million miles. Steady binoculars or any small telescope will reveal Jupiter's four traveling companions, discovered by Galileo in 1610. They are the four largest of Jupiter's 67 known moons — Io, Europa, Ganymede and Callisto.
Watch, from night to night, as they dance around Jupiter and constantly change their positions. On the night of opposition, Jupiter will shine only one-third of a degree away from a little star called Theta Virginis. Don't confuse it with one of Jupiter's moons.
Through a medium-sized telescope, you also can see the two dark cloud stripes straddling Jupiter's equator and maybe even the famous Great Red Spot. Jupiter will remain close to Virgo's alpha star, Spica, all year, offering a great opportunity to prove to yourself that stars "twinkle" but planets don't.
June 15: See Saturn at its best
Saturn is the second bright outer planet to reach opposition in 2017. Every 378 days, the Earth gains a lap on the sluggish planet Saturn and passes directly between Saturn and the sun, placing the two planets as close together as possible.
When Saturn reaches opposition June 15, it will be 9.05 astronomical units, or 841 million miles from Earth, its closest point for 2017. Saturn will rise in the eastern sky at dusk and shine brightly all night, from sunset to dawn.
This year, Saturn shines down on us from the unofficial 13th constellation of the zodiac, Ophiuchus, the Serpent Bearer, about a hand span at arm's length from Scorpius' alpha star, Antares. A telescope of any size aimed at Saturn will reveal its beautiful icy rings and the largest of its 62 moons, planet-sized Titan.
On June 9, the nearly full Milk Moon will rise alongside Saturn. The nearly full Thunder Moon returns for an encore performance a month later on July 6. Saturn's rings are tilted their maximum toward Earth this year, so don't miss this chance to see the solar system's crown jewel at its best.
Aug. 12: Watch the Perseid meteor shower before dawn
The annual Perseid meteor shower is among the best of the year. We experience this shower of "falling stars" every August, because Earth plows head-on into the dust swarm left behind by a comet named Swift-Tuttle.
If the sky is dark and clear, a single observer usually can count about 60 to 90 meteors per hour during the shower's peak between midnight and dawn Aug. 12, with smaller numbers seen for about a week on either side of the peak.
The Perseids tend to shoot across the sky in brief flurries of two or three, with several minutes of calm between. The meteors will seem to spring out of the constellation of Perseus in the northeastern sky, just below the famous W-shaped constellation of Cassiopeia.
On the night of peak activity, Aug. 11 and 12, the waning gibbous moon will rise around 9:30 p.m. and shine all night, but you shouldn't have any trouble spotting dozens of bright Perseid meteors if you put the moon to your back or behind the corner of a building.
Perseid meteor watching makes a great late-summer family activity. Take the kids to a nice, dark location, roll out the sleeping bags and watch the fireworks. See who can count the most meteors.
Aug. 21: Total eclipse of the sun
Total eclipses of the sun by the moon are not rare. There's usually at least one somewhere on the Earth's surface every year. The problem is that the area of visibility is very small, so you either have to be lucky enough that it happens close to where you live, or you have to travel a great distance to put yourself in the right spot.
The most recent total eclipse of the sun visible from the 48 contiguous states was Feb. 26, 1979. That one was visible only from a few extreme northwestern states and across central Canada.
On Aug. 21, the moon's shadow will sweep across the U.S., from sea to shining sea, including parts of Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, North Carolina, Georgia and South Carolina. The shadow path is not very wide — only 70 miles across — so, unless you are situated within that path, you get the "close but no cigar" award.
From Craig, the sun will be 94 percent eclipsed and from Steamboat Springs, 95 percent eclipsed. This ain't horseshoes, gang. Close doesn't count.
If you want to see the mysterious shadow bands, eerie darkness with stars shining at midday, Bailey's Beads and the Diamond Ring, the stunning solar corona and prominences, then do whatever it takes to put yourself in that path of totality. It's a short drive up to central Wyoming for the most stunning and breathtaking two and a half minutes you've ever experienced.
For viewing the partial phases of the eclipse, before and after totality or from anywhere outside the total eclipse path, you will need a safe solar filter to protect your eyes from the intense sunlight. Maximum eclipse for northwestern Colorado happens between 11:40 and 11:45 a.m.
The next total solar eclipse across the continental U.S. happens on April 8, 2024, but that one won't come as close to Northwest Colorado. This is your big chance. Don't blow it.
Sept. 1: Venus very close to the Beehive Star Cluster at dawn
Venus is a beautiful sight all by itself, but when it is seen with a swarm of glittering stars behind it, it is spectacular, indeed. Early risers or night owls will have that opportunity before dawn Sept. 1, when Venus will shine beside the Beehive Star Cluster in the constellation of Cancer, the Crab.
You'll need a clear view of the eastern horizon and a pair of binoculars for this top 10 event. Start looking due east about 4 a.m., when Venus is just a few degrees above the horizon.
With binoculars or a small telescope on low power, you'll spot the star cluster less than 1 degree to the left of Venus. Also called The Praesepe (Manger) and Messier 44, the Beehive Star Cluster contains about 1,000 stars and shines on us from a distance of about 550 light years.
As dawn brightens the sky that morning, the little "bees" of the Beehive will fade from view, but dazzling Venus will shine through until sunrise.
Dec. 14: Geminid meteor shower sparkles
The annual Geminid meteor shower almost always makes my top 10 list of celestial events. Geminid meteors shoot out of our constellation of Gemini, near the bright stars Castor and Pollux, and are caused by tiny bits of debris from the asteroid or burned-out comet named Phaethon.
Geminid meteors tend to be long, slow and bright. Under ideal dark sky conditions, a single observer can expect to see from 90 to 120 meteors per hour at the peak of activity.
This year, the waning crescent moon won't rise until nearly 4 a.m., so meteor watching can begin as early as 8 p.m. the night of Dec. 13 and 14, when the constellation of Gemini breaks the northeast horizon.
In general, the meteor counts tend to increase in the hours after midnight as Gemini rises higher in the sky. Lesser numbers of Geminid meteors can be seen for several nights before and after the peak, too, so bundle up, take advantage of those clear, crisp December nights and see how many Geminids you can spot this year.