Recent Astronomy Articles at Cosmic Pursuits

Mercury, the Pleiades, and the Hyades

May 2, 2015 by Brian Ventrudo Filed Under: Solar System

It’s a good time for seeing planets. Venus moved past the Pleiades and Hyades star clusters in early April. Now it’s Mercury’s turn. In this image, you see the speedy little planet near the two famous star clusters on May 1, 2015. The Hyades star cluster is tangled in the branches at left. For the next week, Mercury makes its best appearance this year in the western sky after sunset. Venus is much higher above the horizon after sunset, and Jupiter higher still. Saturn rises in the east before midnight, its rings tilted dramatically, as it moves to its closest approach to Earth later in May.

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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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Chandra’s Limit

April 30, 2015 by Brian Ventrudo Filed Under: Uncategorized

Thursday, April 23, 2015

1. Chandra’s Limit

In which your publisher recounts his youthful brush with astrophysical greatness, and attempts to explain why there are no fat white dwarf stars in the universe. (Yes, the two topics are related… sort of).

2. Mercury Appears… and Gets Smacked!

Just as the planet Venus skimmed the Pleiades star cluster after sunset a few weeks ago, the tiny planet Mercury does the same this week on April 30, 2015. You can see planet and star cluster low in the northwestern sky just after sunset. And remarkably, on the same day, NASA’s MESSENGER spacecraft ends its mission by slamming into Mercury at 8,000 mph. It’s a big day for the little planet!

3. Messier 13 Returns

As a chronic insomniac, I often wander out late at night to see what’s coming over the eastern horizon (fact: you can tell how little sleep I’ve had by the average number of typos in these emails). Anyway, I noticed mighty Hercules wheeling into view last week, which brought me thoughts of my favorite summer stars. This short piece on M13 will help get you in the mood for stargazing, and it features a fine image from a young stargazer living in the washed out skies of London, U.K.

4. A Conspiracy of None

The final article on the ‘retired’ One-Minute Astronomer site tells of the return of the mysterious ‘white spots’ on the dwarf planet Ceres. The spots returned to view this week as the Dawn spacecraft maneuvered into a different orbit to take a look at the lighted side of this small world. The conspiracy theorists have been silenced… for now.

+ Extras

Finally, for you astronomical art collectors out there, my friend Terry Hancock is offering for auction on eBay a signed one-of-a-kind aluminum print of his magnificent image of Orion ‘Clouds of Creation’. The print is 40″x95″ on an aluminum base that has the gleam of a new car finish. ideal for the rich detail in this panorama. The image on this museum-grade print was made from 420 individual exposures. See the auction at this link…

Wishing you clear skies,

Brian Ventrudo
Publisher, Cosmic Pursuits
CosmicPursuits.com

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New Image of Pluto and Charon from ‘New Horizons’

April 29, 2015 by Brian Ventrudo Filed Under: Solar System

Just 11 weeks left to go until the closest flyby of New Horizons by Pluto. These images, released on April 29, 2015, show Pluto and its largest moon Charon, which is as large as Texas, revolving about their common center of mass. You can also see Pluto rotating about its own axis, ‘like a chicken on a BBQ spit’. Most amazingly, there are surface features visible on the surface of Pluto including a bright patch at one of the poles. NASA explained that these surface markings are remarkably visible compared to other planets given the distance and size of Pluto. These constitute the most detailed images ever captured of the ‘former planet’. The view will only get better from here.

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See the Eta Aquariid Meteor Shower

April 27, 2015 by Brian Ventrudo Filed Under: Solar System

An Eta Aquariid meteor over the Devil's Tower in Wyoming (credit: David Kingham) — An Eta Aquariid meteor over the Devil’s Tower in Wyoming (credit: David Kingham)

The annual Eta Aquarids occur as Earth passes through an stream of icy and dusty debris from the famous Comet 1/P Halley, more commonly called Halley’s Comet. We pass through a second stream of the comet in late October. This results in the Orionid meteor shower. So if you missed the comet during its last apparition in 1986, you can at least see sand-grain-sized bits of the comet burn up in the atmosphere during these two meteor showers.

The Eta Aquarids gets its name from the 4th magnitude star Eta Aquarii in the constellation Aquarius. The star is 168 light years away and bears no physical relation to the meteor shower. But the meteors appear to trace their paths back to a point in the sky near this star as the Earth moves into the debris field.

Because Aquarius lies on the ecliptic well south of the celestial equator, this is a better meteor shower for observers in the southern hemisphere. Rates of 30-60 meteors per hour are typical. Northern stargazers can see perhaps half as many near peak, but it’s still an impressive event. The Eta Aquarids on average are quite speedy and enter the atmosphere at 66 km/s (148,000 mph).

As with most meteor showers, the hours before ~~twilight~~ dawn, as the Earth turns into the meteor stream, are the best time to see the Eta Aquarids. You don’t need to find the star Eta Aquarii to see the meteors. They can appear anywhere in the sky. You don’t need any optics… just lie back under dark sky and look up.

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