Summer astronomy from home

Yesterday I did an interview with a writer who is working on an article for a regional travel magazine. Its editors have concluded that most folks aren’t so anxious to go anywhere right now given our situation with coronavirus and stay-at-home orders. They correctly note that astronomy is something that one can enjoy without venturing too far afield.

It’s true! The sky is everywhere. All you have to do is look up! There are lots of interesting things to see that don’t even require a telescope or binoculars. Here’s a quick look at just a few of the things headed our way this spring and summer.

Venus 

Venus is the queen of the evening hours these days and is high in the west at dusk. She’s flirting with the Pleiades, the Seven Sisters, and will be closest to this gorgeous star cluster tomorrow, April 3. The Sun will set around 7:40 p.m. Pacific time. Give it until a little after eight for the Pleiades to appear, then they and Venus will hang out together until they all set a bit after 11 o’clock. If you have binoculars or a telescope take a closer look to spot the phase of Venus. It’s a pretty thin crescent right now. The Pleiades look great through binoculars, too!

Comet ATLAS 

Discovered in December, the comet ATLAS, so-named because it was first spotted by astronomers using the Asteroid Terrestrial-impact Last Alert System in Hawaii, has some folks thinking it may become a highly visible naked-eye object, perhaps the best in 20 years. Comets can be pretty fickle, and such predictions are often the kiss of death. But it doesn’t cost anything to keep an eye out.

This article from EarthSky explains how to find ATLAS. If it’s going to be spectacular, that will happen later this month through most of May. Maybe.

Parade of planets 

Your view of Jupiter from your back yard won’t be
quite as great as the 2016 Hubble Space
Telescope photo. Credits: NASA, ESA, and
J. Nichols (University of Leicester)

Mars, Jupiter, and Saturn are keeping pretty close company in the pre-dawn sky these days. You can spot all three low in the southeast after about 4:15 a.m. when Mars rises, the last of the trio to peek above the horizon. Mars will appear to move east of the others in the coming weeks and months, but Jupiter and Saturn will stay pretty close together all summer. They reach opposition on July 14 and July 20, respectively. Mars reaches opposition on October 13, and this year’s apparition of the Red Planet will be a good one. They aren’t great naked-eye targets, but Neptune will be at opposition on September 11 and Uranus will be opposite the Sun on Halloween.

Meteor showers 

The Perseid is probably the most well-known of the annual meteor showers. Maybe that’s because it’s pretty consistent and happens in the summer when folks don’t mind being outside in the evening. This year’s peak will occur around August 11-12. The last quarter Moon will brighten the sky somewhat at that time, making some of the dimmer meteors difficult or impossible to spot. While you can catch many of the brighter meteors even from light-polluted cities, the darker the sky you have, the better the show. The Lyrid meteor shower peaks around April 22 and the Eta Aquarids May 5. EarthSky has a full rundown of the year’s meteor showers.

Keep looking up!

Hubble's latest pic of Saturn is a pretty good one

The notion of a picture being worth a thousand words can often be an understatement. Witness the newest, just-released photo of Saturn captured by the Hubble Space Telescope.

The NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 observed Saturn on 20 June 2019 as the planet made its closest approach to Earth this year, at approximately 1.36 billion kilometers (845 million miles) away. (Photo: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley))

This image is the second in a yearly series of snapshots taken as part of the Outer Planets Atmospheres Legacy (OPAL) project, according to news releases from the European Space Agency and the Space Telescope Science Institute. OPAL is helping scientists to understand the atmospheric dynamics and evolution of our Solar System’s gas giant planets. In Saturn’s case, astronomers will be able to track shifting weather patterns and other changes to identify trends.

Enceladus and the platinum age of planetary exploration

Ours is a great time to be alive if you have an interest in learning about other worlds, at least according to Ron Hobbs, a NASA Solar System Ambassador and museum educator and public programs assistant at Seattle’s Museum of Flight.

“For most of us the golden age of planetary exploration was the ‘70s and early ‘80s,” Hobbs said. “The time of the Apollo Moon missions—particularly those that did a lot of science—the Viking missions to Mars, and of course Voyager.”

At least four distinct plumes of water ice spew out from the
south polar region of Saturn's moon Enceladus in this dramatically
illuminated image, shot on Christmas Day 2009 by Cassini.
Light reflected off Saturn is illuminating the surface of the moon
while the Sun, almost directly behind Enceladus, is backlighting
the plumes. Photo: NASA/JPL/Space Science Institute.

After that, things slowed down a lot, but in recent years there’s been something of a renaissance in the solar system.

“The first decade of the 21st Century has been as good as, if not better than, the golden age,” Hobbs believes. “Some people have called it the platinum age of planetary exploration. And if there’s a flagship of that platinum age of planetary exploration it’s got to be the Cassini-Huygens spacecraft.”

Hobbs gave a talk about Cassini, titled “Seven Years in the Saturn System,” last month at the museum. The presentation featured lots of the spectacular photography from the mission, including the discovery of seasonal colors on the second-largest planet in the solar system. Hobbs also discussed discoveries about Saturn’s rings and the intense study of the huge moon Titan. But the most fascinating part of the talk centered on the moon Enceladus, which Hobbs says has joined the astrobiologists’ short list, along with Mars and Europa, for further study.

That’s largely because of the discovery of enormous geysers at the south pole of Enceladus, which spew out ice crystals that form Saturn’s E-ring and cover Enceladus with fresh snow, making it one of the brightest objects in the solar system. The interesting thing about the E-ring is that it contains salt.

“The salt had to come from somewhere,” Hobbs explained, “so somewhere down in Enceladus there must be water in association with hot rocks. So you’ve got an energy source, you’ve got water. We don’t know yet, but maybe we have organic chemicals. If we do, this becomes one of the likeliest places we could find life in the solar system.

“Enceladus has rapidly become one of the most important bodies for us to study,” he added.

Cassini’s work in the Saturn system is planned to continue until the summer of 2017, when it will make a handful of spectacular proximal orbits very close to Saturn’s cloud tops before it runs out of fuel and is crashed into the ringed planet.

That’s presuming Cassini keeps working. Hobbs notes that while the warranty has long since expired, the school bus-sized craft hasn’t missed a beat since it was launched in 1997.

“Space is a harsh environment, particularly when you go a billion miles from the Sun,” Hobbs noted. “It gets cold out there, and every time you go into the shadow of Saturn or one of the moons, it drops dramatically. So given our experience with technical things, it is kind of a surprise” that Cassini is still functioning, he said. “On the other hand, we in America seem to be building some really good stuff these days.”

It will be fascinating to see what wonders Cassini finds before the mission ends five years from September.

Storm on Saturn, and a Voorwerp

There are a couple of great new posts up on Alice’s Astro Info by Alice Enevoldsen this week.
The first, Storm on Saturn—With a Tail, was posted Sunday. It’s a great summary of a new storm that turned up on Saturn at the end of 2010. It’s about the same size as the Great Red Spot on Jupiter.

Cassini captured this photo of the storm on Saturn on Christmas
 Eve, 2010. Photo: NASA/JPL/Space Science Institute.

We tried to spot this storm from Seattle Astronomy headquarters in West Seattle during that rare, clear weather we had over the holidays. Alas, while we had a couple of good looks at Saturn, it was still pretty low in the sky, a bit murky, and we couldn’t make out enough detail to spot the storm. (St. Nick delivered a new Tele Vue 10mm Radian eyepiece we were hoping would help tease it out, but even great new optics didn’t get us there.) Even today Saturn isn’t rising until a little after midnight. It’s plenty high before sunrise, but we’re a lot better at staying up until 3 a.m. than we are at rising at 5:00, so we haven’t seen the ringed planet at its best, and probably won’t until it’s at opposition in early April.

We’re rolling the dice by waiting to try to see this storm. While the Red Spot has been around for centuries, this Saturn storm popped up out of nowhere and could fade back into the yellow-orange haze of Saturn just as quickly.

The other new article, posted today, is about Hanny’s Voorwerp. It looks kind of like an enormous cosmic frog in an amazing Hubble photograph included in the post, but in actual fact is a light echo. Enevoldsen is a physics and astronomy genius and explains the phenomenon very well. I just think it looks cool. And I like to type the word Voorwerp. Voorwerp, voorwerp, voorwerp. It’s Dutch for “object,” and Hanny’s Voorwerp was discovered by a Dutch schoolteacher using Galaxy Zoo.

Keep an eye on Alice’s Astro Info for great notes about what’s up in the sky.