The Earth captured at summer solstice, 2017 – Credit: Japan Meteorological Agency’s Himawari-8 satellite
Ah, summer. Leisurely days spent sipping ice tea by the pool or barbecue. Or maybe a vacation on a beach or lake? Or a trip overseas? There’s just something about this favorite season of everyone’s that brings smiles and thoughts of relaxing the sultry days away, maybe indulging too much ice cream and gazing at fireworks.
Summer almost seems like a reward for shivering in winter, raking all those autumn leaves and pulling the enthusiastically growing spring weeds from all those places they shouldn’t be growing. It’s the glamour girl of the seasons, letting down its long, luxurious hair to blow in the west wind, shining brightly in the glittering sun.
But really, summer is just a spot on the Earth’s orbit that means that one of its poles has reached its maximum tilt towards the sun, and from an observer’s viewpoint, the sun has reached its highest point in the sky. And during the northern hemisphere’s summer, anyone south of the equator is entering winter. Or, if you’re at the equator, there’s hardly any shift in time or seasons.
The summer solstice occurs in the northern hemisphere anytime between June 20-22. It’s a quirk of the calendar, not of the Earth. If one also notices the time of sunrise and sunset, you’ll see that sunrise times seem stuck in place for a few days, but the sunset times grow later. The sun in the sky appears to be at the same place for a short while. That’s known as an analemma. Click on the link for a previous blog post that nicely explains what it is.
Skygazers are rewarded with lots of wonderful constellations during the summer. Facing south, both Scorpius and Sagittarius dominate the sky. There’s the Perseid meteor showers from August 8-13. The Summer Triangle too – consisting of three brilliant stars: Deneb in Cygnus, Altair in Aquila and Vega in Lyra. The Milky Way shines brightly above around midnight, and Aquila and Cygnus are poised within it.
While haze might make some nights a bit challenging for observing the sky, viewers should take every opportunity to turn off the porch light and look up. Those stars won’t be hanging around forever. They’re busy marching on to the next season, which is autumn, and in the northern hemisphere it occurs on September 23. So put down your smartphone, turn off the TV and get outside!
September’s usually a loaded month, for all sorts of reasons. Kids head back to school, there’s a big holiday capping off the traditional summer holiday, all the zucchini’s either ripened at once and your neighbors run from you as you clutch your harvest, chasing them, and we turn the season from boiling to pleasant.
There’s all sorts of things going on above our heads as well. We started off the month with a solar eclipse today, in Africa. That means in two weeks, we’re going to see a lunar eclipse on September 16. Solar and lunar eclipses always appear in pairs, about two weeks apart. This time, the penumbral lunar eclipse will be visible throughout all of Europe, Asia, Australia, but not North and South America, except for the easternmost part of Brazil.
If you know your constellations, Scorpio is crawling back down southwest to get away for the winter. It’s taking with it a colorful trio of two planets, a star and one moon…but just for a day or two. Around the second week of September, you’ll see Antares, a big red star located in the upper portion of the constellation, Saturn to the upper right and Mars to the upper left. The moon on the half-shell will add its glow to the grouping.
September’s a fine month to spot the so-called Summer Triangle, a trio of constellations (The Swan, The Eagle and The Lyre) forming a jewel of a triangle consisting of two first magnitude stars and one zero magnitude: Vega (0.14 mag) in The Lyre, Altair (0.89 mag) in The Eagle and Deneb (1.33 mag). With luck, you can see this grouping almost all year round, but the best time for it is during the summer, when it’s nearly overhead in the Milky Way. Vega is especially close to Polaris, the North Star, and only goes below the horizon at latitudes 40 degrees for a handful of hours. The further north you go, the longer you can see it.
On Thursday, September 22, 2016 at 14:21 UTC, autumn officially begins in the northern hemisphere. That’s when you start thinking about how fast that summer went past, you still didn’t get to the beach, but that’s okay, because you can’t get into your bathing suit anyway. So why don’t you do yourself a favor? Toss on a sweater, take a chair and have a seat, looking up at the greatest gift we all have at our disposal: the heavens.
Autumn, fall, change of the seasons, whatever you call it, occurs in the northern hemisphere on September 23 at 8:20 UTC. It’s a time when things start winding down in gardens, the kids are probably already back in school and you’re looking at your heating bill with a bit of trepidation, knowing that winter’s beating a steady path to your door.
But let’s stick with autumn for now.
Autumn occurs when the sun hits a point in the sky called the autumnal equinox, or here:
Credit: H.A. Rey, “The Stars”
It’s the little “V” you see underneath Virgo’s head, as if she fell down and tripped on the ecliptic (the path in the sky where the sun, moon and stars “travel” along the zodiac). The sun hits this spot on or about 21 September each year, but as noted above, this year it falls on the 23 September. But if you look in the newspaper or even on many weather web sites, you’ll notice that the times of sunrise and sunset are anything but equal. It’s close, but not exactly 12 hours of day and dark. A lot of that depends upon your latitude. The further south you go, that date creeps into October.
Here’s a handy chart to show sunrise and sunset times for New York You’ll see day and night aren’t equal until September 26. Why? You’ll find an explanation here.
This National Geographic video explains not only the autumnal equinox, but also nifty cultural practices that go along with it.
(You might want to watch it before Rupert Murdoch gets ahold of it and turns it into an exploitive clip about the sun ripping off the nighttime sky by getting dark earlier and earlier).
Want to hear the definitive theme song of autumn? Here’s a short, catchy tune by the band Screeching Weasel called “First Day of Autumn”:
Most important of all, nighttime sky watches CAN’T MISS the total eclipse of the moon! It takes place on September 27/28, 2015. Click here for details to look out for it in your neck of the woods. In New York, it actually begins at a decent time, starting at 8:11 pm, with the full eclipse occurring at 10:11 and lasting until 10:47. If you haven’t seen a total lunar eclipse, it’s worth watching. It’s a slow process, but you’ll have time to truly enjoy it. Don’t take your eyes off of it between 9:50 and 10:15 – watching the moon turn red is the coolest thing ever. Break out your binoculars!
There’s a tiny, disk-sized patch of snow behind the museum where I work, a reminder that winter wasn’t all that long ago. I keep waiting for it to melt, but it refuses, so I ignore it and remember that its water’s going to water the grass it’s hiding. In defiance, some crocuses finally gathered the gumption to bloom – a month late – and later the daffodils joined in.
Ah, spring!
But if that snow didn’t want to release its chilly grip on Earth, all I had to do was look up and see the spring sky greet me. Clouds are the only impediment to these yearly harbingers of warmer times.
I’ve got a few favs I eagerly look for when the days begin to lengthen. When Leo starts strutting up that heavenly hill come February, spring isn’t far behind.
There’s no mistaking him. He’s got a jewel on one foot, Regulus, magnitude 1.4, and sports another in his tail, Denebola, a bright second-magnitude (2.14) star. He leads the parade for my next favorite grouping:
Bootes, the Herdsman. You can’t mistake him either, although he’s so large it’ll might take a little patience to find him. His main-feature star, Arcturus, lights up his lap. He’s sitting down, smoking his pipe, wondering how all those sheep he was supposed to watch disappeared (perhaps Leo ate them?).
Or maybe he’s just trying to hide that hunk of bling behind him, the Northern Crown, or Corona Borealis. It has a second-magnitude star, Gemma, actually a binary star, or two stars rotating around each other. Its magnitude shifts from 2.21 to 2.32, not very noticeable with the unaided eye. You’d need seventeen straight days to stare up at it with a telescope to measure the change.
Credit: Till Credner (Own work: AlltheSky.com)
We all know how lions pride themselves on their gorgeous manes. Bootes must share the same sentiment, because between him and Leo, there’s a fantastic group of very faint stars known as Berenice’s Hair.
It’s small, but that doesn’t make it special! There are eight galaxies within it, several globular clusters, 200 variable stars in its region and if that weren’t enough, the North Galactic Pole is amidst her strands. But wait! There’s more! She gets all twinkly and festive during the Christmas season. Bragging her own meteor showers during December and January, she peaks from December 18-25, right in time for the holidays. It’s also important, when looking at her, not to expect to spot the Milky Way. When her hair is high in the sky, the Milky Way is lower in the sky, on or near the horizon.
And speaking of meteor showers, in mornings you’ll find the Lyrids, or meteor showers occurring near the constellation Lyra. Those occur at the end of April, peaking between April 22-25. The radiant is where to look; the meteors seem to be originating from that point.
Credit: astrobob.areavoices.com
Now, get off that couch, stop texting, get outside and go have yourselves a great look at the nighttime sky!
Moon, Stars and Beyond 