Stargazing

General articles and links about astronomy and the night sky.

Aurorae at Summer Solstice

June 24, 2015 by Brian Ventrudo Filed Under: Stargazing

(The Great Solstice Aurora from Alan Dyer on Vimeo).

The Sun flared late last week and sent a series of coronal mass ejections in our direction. The high-speed charged particles smacked into the Earth’s upper atmosphere on June 22, 2015, and ignited aurorae borealis as far south as Georgia and Virginia, for example. The deep-southern hemisphere had fine shows of aurorae australis as well. If you missed these splendid vistas, the striking timelapse by astrophotographer Alan Dyer will give you a taste of the intensity and color of the display. Dyer is a master of nightscape and timelapse photography, and when he learned of the possibility of a striking auroral display, he packed his equipment and set to work. He wrote of his impromptu timelapse project on the night of summer solstice: [Read more…] about Aurorae at Summer Solstice

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Alpha Centauri Through a (Really) Big Telescope

May 14, 2015 by Brian Ventrudo Filed Under: Stargazing

1. Alpha Centauri Through a (Really) Big Telescope

The razor-sharp images afforded by Earth-based telescopes with high-tech adaptive optic systems often rival images from space-based scopes like Hubble. But is it possible to look through the eyepiece of one of these big scopes? A select group of professional astronomers did just that. They peered through the 6.5 m Magellan telescope at Las Campanas Observatory and saw the two brightest stars in the Alpha Centauri system split as wide as a church door. By contrast, this is what the two stars look like in a small amateur telescope.

2. Venus Brightens

Venus, already tremendously bright and high in the western sky after sunset, is now tangled in the feet of Gemini in the northern Milky Way. The planet reached its highest point above the horizon last week and now slowly sinks in the west on its way to a photogenic rendezvous with Jupiter on the last day of June.

3. A Paradise Lost?

Speaking of Venus… the planet is similar to Earth in size and mass, and lies within the zone in which a planet might be habitable. Yet Venus has a distinctly un-Earth-like environment. It’s a pressure-cooked hellhole of a world hot enough to melt lead, a place where rain falls in the form of battery acid. But Venus may not always have been so unpleasant. About 650 million years ago, the planet was wracked by volcanic activity that covered much of its surface in lava and turned the planet into a giant toxic greenhouse. A pair of planetary scientists recently found evidence that Venus may once have had tectonic activity, continents, and perhaps even oceans, and may have been a much more hospitable place.

4. Eta Carinae: The Next Supernova?

The Eta Carinae Nebula, the jewel of the southern-hemisphere constellation Carina, the Keel, is the most spectacular example of an active star factory in all the heavens. In this excerpt from an upcoming e-book about the most striking nebulae of the Milky Way, you get a close look at this star-forming region that harbors a star that’s too big to be stable… or to last for much longer.

5. A Video Game As Big As A Galaxy

I last played a video game when Ronald Reagan was early in his first term. Life’s too short, I say, to muck around in front of a game. The real world is interesting enough. But this may change. A new game called “No Man’s Sky” is due for release at the end of the year, and it’s a jaw-dropping extravaganza of imagination and computer science that enables the ‘player’ to navigate and explore more than 18 quintillion unique planets. The ‘universe’ in this game is designed using natural laws that determine the age and composition and physical characteristics of stars, planets, and life. Early video clips are awfully impressive. A feature on the creation of the game is out this week in the New Yorker.

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100,000 Galaxies, No Signs of Life

May 7, 2015 by Brian Ventrudo Filed Under: Stargazing

1. Mercury Lingers in the Western Sky

The tiny planet Mercury lingers in the western sky after sunset, still tangled in the lacework of star clusters in the constellation Taurus. The planet reaches greatest eastern elongation on May 7, 2015 at an angular distance of 21º from the Sun. Mercury is visible over the next few days about 10 degrees above the NW horizon for northern-hemisphere observers, and just 5 degrees above the horizon for southern-hemisphere observers. Here’s what to look for in the next few days…

2. 100,000 Galaxies, No Advanced Aliens

Now to a superb think piece by Lee Billings about a recent search for advanced alien civilizations in other galaxies. While it may sound far-fetched, the search was grounded in hard science. Assuming advanced civilizations have learned to harness the energy of stars to build solar-system-wide habitats, we should be able to see the waste energy in the form of infrared (IR) light over and above the background light of a galaxy. After searching 100,000 galaxies for excess IR, no sign was found beyond what’s expected from natural processes. So maybe there are no advanced civilizations, at least yet. Or perhaps there’s a subtler answer… that advanced life, assuming it exists, might evolve to be efficient and integrated with its natural environment. It’s a fascinating read.<

3. Panorama of the Virgo Galaxy Cluster

It’s galaxy season! Between the constellations Leo and Virgo, in a patch of sky no larger than your outstretched hand, you can see dozens of the more than two thousand galaxies of the Virgo cluster, the largest major galaxy cluster to our Milky Way. Have a look at this superb image of part of the Virgo cluster taken with a backyard telescope, and learn a little about how galaxy clusters evolve….

4. Sailing Stones and Splendid Stars

The last few years have seen an explosion of nightscape photography, a combination of landscape and astrophotography using new DSLR cameras with the latest large, low-noise sensors. It’s not an easy form of photography, least of all because you need to stand in complete darkness, in the middle of nowhere, for hours at a time. But I love this art form. One of my very favorite nightscapes is by David Kingham, who from Death Valley, California, managed to image a remarkable “sailing stone” in a dried mud flat with the stars of Orion and Canis Major in the background. It’s a superb piece of photography.

5. From the ‘Observer’s Log’ – The Splinter Galaxy

>Finally this week, just to show that sometimes I get to do a little stargazing myself, I present a short observing report from my ‘observer’s log’ taken during a night of backyard galaxy hopping.

Wishing you clear skies,

Brian Ventrudo

Publisher, Cosmic Pursuits

CosmicPursuits.com

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Eta Aquariid meteor shower peaks this week

April 30, 2015 by Brian Ventrudo Filed Under: Stargazing

Thursday, April 30, 2015

1. See the Eta Aquariid Meteor Shower

The usually reliable Eta Aquarid meteor shower peaks on the night of May 5-6 this year. The shower runs from April 21 – May 20, 2015, with many meteors still visible for several days on either side of the peak. It’s perhaps the best meteor shower of the year for southern hemisphere stargazers, and it’s pretty good for northerners too. The meteors are sandgrain-sized bits left over from Halley’s comet. Like most such showers, the best viewing is just before dawn.

2. Lights Out for Dark Energy?

Astronomers at the University of Arizona announced one of the ‘standard candles’ of the universe, exploding stars called Type Ia supernovae, may not be so standard after all. They found more distant Type Ia supernovae might be intrinsically fainter than more nearby events, suggesting the accelerating expansion of the universe is not as pronounced as once thought. This may mean the effect of the mysterious ‘dark energy’ that causes the expansion is also less important. But that doesn’t disprove the existence of dark energy. As Ethan Siegel explains, there are two more independent observations that show something like dark energy (whatever it may be) still accounts for the majority of the universe.

3. New Images of Pluto and Charon

Yesterday, NASA released rather stirring images from the New Horizon’s spacecraft of Pluto and its Texas-sized moon Charon revolving about their common center of mass. The images also show Pluto rotating about its axis, and large-scale surface features on the former planet’s surface. These are the best images yet captured. The view will only get better as New Horizons gets closer to its brief but historic rendezvous with Pluto just 11 weeks from now.

4. Happy Birthday, Hubble

Well, this makes me feel old, but NASA marked the 25th anniversary of the launch of the Hubble Space Telescope last week. The redoubtable instrument, which began its career with a malformed primary mirror, has revolutionized professional astronomy and helped astronomers to generate more knowledge and understanding of the universe in the past 25 years than in the previous 200 years. Hubble helped refine our understanding of the age of the universe, detect atmospheres on exoplanets, and find millions of galaxies in parts of the sky where no galaxies had been seen before. The New York Times has a brief retrospective video on the launch and legacy of Hubble. And Phil Plait published his favorite “12 1/2” images from Hubble in his column at Slate.

5. Jupiter Through an iPhone

Ottawa-based stargazer Andrew Symes continues to refine his imaging techniques using an iPhone and an 8″ Celestron NexStarSE telescope. An iPhone! The small sensor and pixel sizes of smartphone cameras make them unlikely candidates for astrophotography. But clever developers have created apps that enhance the low-light operation of the iPhone camera. So with a little practice and standard post-processing techniques, Symes has shown it’s possible to take quite acceptable images of Jupiter, Saturn, the Moon, and even brighter deep-sky sights directly at the eyepiece of a telescope with an iPhone.

Wishing you clear skies,

Brian Ventrudo
Publisher, Cosmic Pursuits
CosmicPursuits.com

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