Recent Astronomy Articles at Cosmic Pursuits

The Sky This Month – August 2017

August 1, 2017 by Brian Ventrudo Filed Under: Celestial Events

Image of the 2015 total solar eclipse over the Faroe Islands. Credit: David Byrne at Flickr.com

2 August. Look for sand-colored Saturn to the south and west of the waxing gibbous Moon, and north and east of the red-orange star Antares. Well past opposition, the planet is still a dazzling sight in a small telescope all month. Its rings are tilted near maximum, about 27º, the greatest in 15 years, and the planet’s disk is still a respectable 18″ across. If you’ve got a telescope, make some time to see Saturn this month. It’s a beautiful sight [Read more…] about The Sky This Month – August 2017

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The Mysterious Hiss from the Milky Way

July 22, 2017 by Brian Ventrudo Filed Under: Science

The northern summer Milky Way. The center of our galaxy lies just above the tree at lower center in this image. The Bell Labs radio engineer Karl Jansky discovered radio emissions from this location in the early 1930s. Image credit: Brian Ventrudo/CosmicPursuits.com.

In the early 1930′s, Bell Labs, the research division of AT&T, launched a project to use radio “short waves” to transmit telephone calls across the Atlantic. The technology to transmit signals via short waves was reasonably well understood. But engineers also needed to understand sources of noise that might interfere with radio communications signals. So the powers-that-were at Bell Labs tasked a young engineer to find sources of radio static that might interfere with transmissions. During his work, this young engineer, Karl Jansky, made an accidental discovery that revolutionized astronomy [Read more…] about The Mysterious Hiss from the Milky Way

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The Distances to the Galaxies

July 10, 2017 by Brian Ventrudo Filed Under: Science

Multiple images by NASA’s Hubble Space Telescope of the Cepheid variable star that in 1923 altered the course of modern astronomy. Called “V1″, it was first detected by Edwin Hubble with the 100” reflector at Mt. Wilson Observatory. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

In our previous stop on our tour of celestial objects of cosmological importance, we looked at a handful of galaxies measured by the early 20th-century astronomer Vesto Slipher. The former Indiana farm boy wrestled with a modestly endowed telescope and a 450-pound spectrometer to make an astonishing discovery. He found the ‘spiral nebulae’ like Andromeda (M31) and the Sombrero (M104) were moving away from us at astonishing speeds, up to 1000 km/s and far faster than any nearby stars. The speeds of these spiral assemblies strongly suggested they lay outside our own group of stars, and were perhaps separate galaxies in their own right far outside our own.

But in science, a strong suggestion is not proof.

In the first years of the 20th century, astronomers had no way of knowing for sure the distance to these spiral assemblies. Indeed, a hundred years ago, they only could estimate the distances to a handful of nearby stars. The true scale of even our own galaxy was a complete mystery. No one knew whether the Milky Way was all there was to the universe, and whether it was a hundred light years across, or a thousand, or a trillion. Never mind the distances to the mysterious ‘spiral nebulae’, which may simply have been nearby star systems in the process of formation.

The key to the distance to the spiral nebulae, which we now know to be separate galaxies, and to the universe itself, lay unexpectedly in a class of unassuming stars, many of which you can see from your backyard with a pair of binoculars or without any optics at all [Read more…] about The Distances to the Galaxies

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The Sky This Month – July 2017

July 1, 2017 by Brian Ventrudo Filed Under: Celestial Events

A delta Aquarid meteor in 2013. Image credit: Mike Lewinski at Flickr.com

The night sky has made its transition from spring to summer, and the bright stars and faint star clouds along the spine of the Milky Way are turning into view in the late evening hours. Saturn is still magnificent over the southern horizon, Venus and Mercury make an appearance at opposite ends of the sky, and July presents your last chance to get a good look at Jupiter before it gets too low in the southwest. There’s also a southern meteor shower this month, one with meteors that enter the Earth’s atmosphere at a shallow angle and leave long, lingering trails in the warm summer sky.

1 July. First Quarter Moon, 00:51 UT

1 July. The first quarter Moon joins Jupiter and the bright star Spica in the southwestern sky. Jupiter is west of Spica and much brighter. This is more or less the last month to get a good view of the planet as it continues to fade, grow smaller, and appear lower in the southern or southwestern sky during July. It’s still brighter than any star and a beautiful sight in a small telescope.

3 July. Earth reaches aphelion, its furthest point from the Sun in its orbit. Today the planet lies 152,092,504 km (94,505,901 miles) from the Sun [Read more…] about The Sky This Month – July 2017

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Guide to Observing Saturn in 2017

June 22, 2017 by Brian Ventrudo Filed Under: Solar System

saturn Many casual observers get hooked on amateur astronomy after a first look at Saturn through a telescope. More than a few have looked through my small refractor on a night of good seeing and asked of Saturn, “Is it real?”

Oh, it’s real, all right. And incredibly beautiful… the color, the proportions, the apparent 3D perspective of this grand icy world. It is arguably the finest sight accessible with a small telescope. The planet reached opposition on June 15, 2017 and will remain bright and large in a telescope over the next few months. Here’s how to find it and see it in a small telescope.

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