Like Saturn and the ice giants Uranus and Neptune, Jupiter has no solid surface. When you see Jupiter through a telescope, you see the middle layers of its gaseous atmosphere. Even the smallest telescope reveals a couple of dark and light bands in Jupiter’s atmosphere. But what causes these bands? And do they change from night to night?
The moon wanes this week, which means the night sky will be dark and ideal for viewing galaxies in Pegasus, Andromeda, and Triangulum. But there’s another spectacle this week… the Orionid meteor shower. Northern observers can enjoy 20-30 meteors per hour over the next couple of nights, while southern observers may enjoy up to 40 meteors per hour in a dark spring sky.
The Draconid meteor shower peaks over the next few days. This shower is usually quiet and obscure, registering just a few meteors per hour. But this year forecasts predict a very active shower of 1 to 10 meteors per minute or more. While it looks like Europe and Asia will get the best show, North Americans should take a look as soon as the sky darkens in case forecasts miss the mark.
There’s an impressive group of spots on the Sun this week and it’s easily visible in a properly-filtered telescope. You may also see some impressive aurorae over the next few nights as a result of increase solar activity…
Last December, the Russian amateur astronomer Leonid Elenin used a remote telescope in New Mexico to discover a new comet that now bears his name. Astronomers hoped Comet Elenin would put on a good show, and perhaps become bright enough to see with the unaided eye by September and October 2011. But things have not gone as planned, though they have become more interesting… at least for comet scientists. Here’s what’s happened…
Here’s an astonishing video of the asteroid Vesta taken from NASA’s Dawn spacecraft, which entered orbit around the asteroid last month. The video is arranged as a flyover sequence, and gives the impression of entering orbit and skimming the surface of this strange, heavily cratered little world in the asteroid belt between Mars and Jupiter. And why not wander outside to see Vesta for yourself on the next clear night…
In the last article, we had a mini-tour of the planet Uranus. Today, let’s step out into the clear September air to find Uranus for ourselves in the night sky, and discover how to observe this distant ice giant in the outer reaches of the solar system.
The planet Uranus is the largest of the two “ice giants” of our solar system and the seventh planet from the Sun. At an average distance of 3 billion kilometres, Uranus lies twice as far as from the sun as Saturn and takes a leisurely 84.3 years to make a single revolution. Uranus was the first planet discovered with a telescope. And it remains a featureless but satisfying target for backyard stargazers.
Just a short message today… many readers are enjoying the last holiday weekend of northern summer, or cleaning up after a big Atlantic hurricane, or struggling with the last clouds of a deep-southern winter.
Just a short message today as I’m packing my optics for an astronomy retreat in New York’s Adirondack Mountains. This retreat, organized by the illustrious comet-hunter David Levy, will be a great chance for me to actually look into clear, dark night sky instead of just writing about it!
And I certainly have a long list of deep-sky sights to observe…
Stargazing is one of the few pastimes tailor-made for insomniacs.
And I’m an incorrigible insomniac.
Which is why I was up looking at the star clusters of Sagittarius last night, and the waning crescent Moon early this morning just after sunrise.
The waning Moon in the deep-blue morning sky is a glorious sight. You can still see hundreds of surface features on the Moon’s surface in early daylight, yet they’re not overwhelming to the eye as they are at night.
Today the planet Neptune completes its first revolution around the Sun since it was discovered in 1846. So it’s a birthday of sorts for this icy blue world. Here’s a brief account of the amazing discovery of Neptune, and a few words on how to look for this most distant of major planets.
A reminder that June 15 marks Full Moon and the first lunar eclipse of 2011. This eclipse will be long and deep and dark, with totality lasting about 100 minutes… the longest lunar eclipse in nearly 11 years.
If you’re in North America, like me, then you’re out of luck for this eclipse, alas. It will totally miss us. But parts of Europe, all of South Africa, India and the Indian Ocean, and Australia and New Zealand will get a fine view.
However… we North Americans (and anyone else who’s interested) can view the eclipse online here…
The 62 moons of Saturn are a fascinating mix of objects, ranging from tiny bodies discovered by close-in spacecraft to the enormous moon Titan, which you can see in a pair of binoculars from your backyard. Fifty-three of Saturn’s moons are named, and thirteen have a diameter larger than 50 km. Just seven of Saturn’s moons are large enough to pull themselves into a spherical shape.
Of this large collection of moons, nine were discovered with telescopes before the age of spaceflight. They are, in increasing distance from Saturn: Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion, Iapetus, and Phoebe. The moons were named after the Titans of ancient Greek legend.
The unexpected large white storm that appeared on Saturn late last year is still going strong. It’s a little harder to see now because it’s spread out in a band across Saturn’s northern hemisphere. But it’s still detectable with a small telescope and good seeing. Here’s a lovely short movie of the phenomenon, taken just last week…
Upon seeing Saturn through a telescope, many first-time observers ask, “Is it real?”
Oh, it’s real alright. And Saturn is primed for viewing over the next few months. So whether you’re starting out in astronomy or you’re a wizened observer with decades of experience, here are a few pointers to help you get the best view of this exquisite planet.
Most stargazers think of the Moon as a blazing-white sight set against the black night sky… beautiful, stark, and jealous for attention, sometimes drowning out fainter, more distant objects.
But for a day or two each month, before the Moon brightens, as its fingernail-thin crescent follows the setting Sun below the horizon, it looks like a completely different celestial body… a completely different Moon.
This excerpt, adapted from Lunar Observing for Beginners, shows you how and when to spot the thin crescent Moon before it sets in the red-orange western sky.
The next installment of the “Bucket List for Backyard Stargazers” was planned for tonight. But let’s turn to Saturn instead. A big storm in the ringed-planet’s northern hemisphere flared up last month, and amazingly, it’s getting even bigger. This is the brightest atmospheric event on Saturn in decades, and it’s large enough now to spot visually in a modest telescope. Here’s where to find the ringed planet, and when to look for this rare and massive storm…
First sight of the Great Red Spot is a high point for any amateur astronomer. Few tire of the sight of this massive and ancient storm in Jupiter’s upper atmosphere. But while it looks fine in photos, it’s surprisingly hard to see in a small telescope. Here are three tips to increase your chances of seeing the “GRS”, and a few words about this swirling vortex that’s large enough to swallow several Earths.
Yet another respectably-bright comet is nearing Earth and will put on a good show for binocular observers. Comet Hartley 2 will be visible in Cassiopeia and Perseus over the next few weeks, and may grow bright enough to see with the unaided eye as it comes within 11 million miles of Earth, one of the closest approaches of any comet in the past century.
Most night-sky sights remain unchanged over the brief months and years of a human lifetime. Yes, yes, you sometimes see the flash of a bright meteor. Or the steady wax and wane of a variable star. Or a few minutes of flickering aurora in the deep northern and southern sky. But nearly everything else seems to change slowly, testing the patience of the most Zen-like stargazer.
And yet, the heavens still hold surprises. Just a couple of months ago, as the massive planet Jupiter emerged from behind the sun, astronomers noticed its thick salmon-hued Southern Equatorial Belt had suddenly disappeared. Its absence can be noticed in the most modest backyard telescope. No one knows why the belt vanished. And if the experts are correct, it could return at any time….
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As backyard stargazers, we spend our time looking up and out towards towards other planets and celestial sights. But today, we have something different… a peek at our own planet from deep space, taken by NASA’s MESSENGER spacecraft. As the saying goes, “You are in this picture”!
The planet Saturn reached opposition this past weekend, rising as the sun sets and making its closest approach to Earth this year. The planet saunters across Virgo over the next few weeks: it’s the brightest object between the stars Porrima in Virgo and Denebola in Leo. This image shows you, roughly, where it is right now. Take a look if you can. Saturn is truly one of the prettiest sights you can see with a telescope.
While no one’s found palm trees and skyscrapers on Mars, there’s still a serious search going on for primitive forms of life on the Red Planet. After all, Mars isn’t all that different from Earth… it has a thin atmosphere and seasons and a source of water somewhere below the surface.
You can see many things when you look at Mars through a small telescope, but you can’t see its two puny moons, Phobos and Deimos. Few have ever seen these moons directly. Even the largest scopes show them as faint points of light. But they’re there, and recent space probes have snapped close-up images of these potato-shaped satellites as they zip and wobble around the red planet.
In an odd way, the presence of Mars’s moons was predicted more than two centuries before they were discovered in 1877.
Mars swings to within 99 million kilometers of our fair planet this week, making its closest approach until 2012. Get your telescope out, or simply look up and gaze at the steady orange-red glow of the Red Planet. It rises in the east in the constellation Cancer just after sunset. You can’t miss it. At magnitude -1.3, Mars almost shines as bright as Sirius, the brightest star in the sky.
Later this week, we’ll give you some tips for observing Mars. Today, we have a few facts and figures about this fascinating world.
As Jupiter lingers in Capricorn this month, why not take a few minutes to step outside into the crisp fall air (or warm spring air if you’re south of the equator) and take a look at the big planet’s four largest moons?
“Oh, I’ve seen them many times before”, you say. “They’re getting a little boring to look at.”
Boring? Come now. When you begin to tire of the beautiful sights in the night sky, it’s time to fire up your imagination. As you look at Jupiter’s four largest moons, Io, Europa, Ganymede and Callisto, you might consider all the areas of art and science these four moons have influenced over the centuries.
We’re mostly visual observers here at One-Minute Astronomer, but we do get questions about how to take images of celestial objects. And with Jupiter hovering in the southwest sky these days, many readers want to know how to take a decent picture of the clouds, zones, and Great Red Spot of the big planet.
If you’re keen to image Jupiter, I have good news and bad news.
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The moon is a thin waning crescent today, which means the night sky over the next week will be dark and ideal for viewing galaxies in Pegasus, Andromeda, and Triangulum. But there’s another spectacle this week… the Orionid meteor shower. And if the experts are right, this year’s Orionids will put on a fine show.
Subscriber R.B. asks, “All I have is binoculars, 10×50, with a 5.5 deg field of view. What could I expect to see?”
The answer is, of course, quite a lot.
With a 5.5 degree field-of-view, R.B.’s 10×50 binoculars show a patch of sky as wide as four fingers held at arms length. That’s a good wide field, ideal for viewing many things at once.
Subscriber E.D. writes, “I wonder if you can help me get a better view of Jupiter. I have a 10” reflector and with a 5mm eyepiece, so I get 240 X magnification of Jupiter and very good resolution. What I lack is contrast. I can see the planet quite large and see the cloud bands, but the red spot is very difficult to see. I’ve tried a blue filter but it’s just very difficult to discern. Do you have any advice for making the red spot really pop out?”
I miss Arthur C. Clarke. He died more than 18 months ago at age 90, but the great science-fiction writer left more than 30 novels and dozens of short stories that described a mostly optimistic vision of mankind’s exploration of space and his responsible use of technology. His most famous work, 2001: A Space Odyssey, was made into what many consider the best science fiction movie of all time.
Our article last week about the zodiacal light resulted in quite a few emails. Seems that many of our readers can see this light, although some didn’t know what it was.
And some of you asked if it’s possible to photograph zodiacal light. In fact, this sight is not too hard to photograph with a simple camera and lens, although taking good astrophotos is a little different than daytime shots. If you’re interested in basic astrophotography with a digital camera, here’s a resource to help you get up to speed quickly…
Now, to today’s business… this one is a little longer than usual, but I think you’ll find it interesting…
“Before the phantom of False morning died,
Methought a Voice within the Tavern cried,
When all the Temple is prepared within,
Why nods the drowsy Worshiper outside?”
- from the Rubaiyat of Omar Khayam
The “false morning” in this 900-year-old passage by the Persian poet and astronomer is not a dreamy literary invention, but a real astronomical phenomenon called the “zodiacal light”. Appearing as a faint, eerie glow before sunrise or after sunset, the zodiacal light has likely been seen by stargazers since since antiquity. And it’s well positioned for viewing over the next month or so by observers in both hemispheres.
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In the mid 19th-century, after many years of diligent solar observation, the German astronomer Samuel Schwabe noticed the number of sunspots visible on the sun’s disk rises and falls in nearly regular 11-year cycle.
In peak years of the cycle, he found, there were spots visible on the sun most days, and hundreds of spots and groups of spots during the course of a year.
In lean years, roughly 5.5 years after the peak, there were weeks or months when astronomers saw not a single sunspot, with fewer than a dozen spots observed during the year.
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In two earlier issues, you learned how to observe the sun (and more importantly, how not to observe the sun).
But why bother observing the sun? What is there to see on our home star?
The answer is… not much. At least right now, though this will likely change very soon. As we’ll explain in coming issues, the sun is strangely quiet this year, which has astronomers deeply puzzled. But most expect the sun will get back to its old self soon enough and generate a number of dazzling sights for observers on Earth.
Jupiter’s moons are at it again.
Last week, on August 26-27, you had a chance to see a double shadow on the face of Jupiter, cast by Ganymede and Europa. I had the good fortune to see this event, and it was a splendid sight (though I’m still paying for the sleep deprivation… a busy schedule makes it hard for your humble publisher to catch up on sleep).
But this week, on September 2-3, you’ll see the extraordinary sight of Jupiter with NO moons. Ganymede and Europa will once again pass in front of the giant planet, while Io and Callisto will pass behind Jupiter from our point of view, making it nearly impossible to visually detect any moons around Jupiter.
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I hope you had a chance to see two of the moons of Jupiter cast their shadows on the face of the giant planet last night. I fought sleep and took my telescope outside to catch the show, and it did not disappoint. Even in my little 4-inch refractor, I could easily see the shadows of Europa and Ganymede. And I saw a third small dark spot I’ve yet to explain. Did anyone else see that third spot? Whatever it was, it was all a lovely sight.
There are more cosmic rendezvous to come this week. On Saturday morning, Mars plays tag with the lovely open cluster M35 in Gemini just before dawn.
As August moves into its final days, Jupiter, the King of Planets, wheels into view late in the evening and promises to put on many fine shows over the coming months. This week, you’ll have a chance to see a rare double shadow on the face of Jupiter cast by the moons Europa and Ganymede.
The shadows come into view from 10:20 p.m. on August 26 to 1:12 p.m. August 27 (that’s 2:20 to 5:12 Universal Time on August 27).
White-light solar filters let you see sunspots and a few other intriguing surface features. But the white light passed by these filters washes out much of the delicate detail from more interesting sights such as solar storms, gigantic solar flares, and violent mass ejections. To see these dynamic features, you need a telescope outfitted with a hydrogen-alpha filter.
The idea behind these filters is fairly simple.
We’re thinking of the sun again today, perhaps because we’ve seen so little of it this summer. But clouds don’t last forever, and when they finally pass, it’ll be time for a little daytime observing of our favorite star…
In the our first article on solar observing, we urged you to use filters that block most of the sun’s rays from entering the telescope. And we reminded you NEVER to let all the light from the sun enter a telescope, and NEVER to rely on a filter at the eyepiece to block concentrated solar rays. It’s just asking for trouble.
But enough of what you can’t do. Here are your options for safe filters for observing the seething surface of our home star…
In 258 A.D., to distract the masses from constant war under his reign, the Roman emperor Valerian ordered the merciless execution of dozens of leaders of the Catholic church. Among those martyred was one of the seven deacons of Rome, Laurentius, just 33 years old. The Roman authorities, rarely subtle, tortured Laurentius by roasting him alive on an iron stove. Though doomed, Laurentius taunted his captors and cried out, “I am already roasted on one side and, if thou wouldst have me well cooked, it is time to turn me on the other.”
Today, we’re kicking off a new series on observing the solar system. And we’re starting at the center of it all with the sun, the closest star to the Earth.
