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Inside the July 2015 Issue

3 hours 45 min ago
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FC_July2015_172px Dwarf Planet(s), Ahoy!

On July 14th, New Horizons will at long last swing past Pluto, collecting better data on this mysterious dwarf planet than we've ever seen before. But, as Emily Lakdawall relates in our cover story, the spectacular data will take many months to trickle in. In the meantime, if you're up for a challenge, you can have your own look at Pluto, and Ceres too, with our detailed sky charts as your guide. You'll find far more to look at in the sky this summer with Rod Mollise's article on summer sensations: start with the Bug Nebula, move on to the Cat's Eye Cluster, and just keep on going. And when the balmy nights fill with clouds, take refuge in Nick Kanas's fascinating and finely illustrated take on the star atlas frontispieces of old.

Feature Articles New Horizons' scientific payload

NASA / JHU-APL / Southwest Research Inst.

Pluto At Last
After a 9½-year flight, NASA's New Horizons spacecraft is making a long-awaited visit to Pluto and its moons.
By Emily Lakdawalla

Planck Upholds Standard Cosmology
The latest analysis of the universe's oldest light provides an exquisite look at the cosmos.
By Camille Carlisle

Celestial Frontispieces of the Golden Age
Astronomy-themed art and allegory reached an early peak as illustrators sought to outdo one another.
By Nick Kanas

The Backyard Sky: Summer
Stretch your observing skills to spot these seasonal sensations.
By Rod Mollise

Done in One
Today's one-shot color cameras can take world-class astrophotos. Here's how to do it.
By Warren Keller

Beyond the Printed Page Disk with names attached to New Horizon

A technician works on the New Horizons spacecraft.
NASA / JHU-APL / Southwest Research Inst.

Prepping for Pluto
Thanks to NASA's New Horizons spacecraft, we're about to see Pluto up close for the first time. Here are a few snapshots of the scientists and engineers who'll make it possible.

Follow Nova Sagittarii No. 2
Stay up-to-date with this unpredictable nova's appearance.

Milky Way's Ripples
Find out more about (and see images of) the waves in our galaxy's disk.

Lunar Librations
Librations and other lunar data for July 2015.

ALSO IN THIS ISSUE Ceres seen as a crescent

NASA's Dawn spacecraft captured crescent Ceres 5 days before arriving in orbit around the dwarf plaenet.
NASA / JPL / UCLA / MPS / DLR / IDA

Summer Sensations
Venus, Jupiter, and Saturn grace the evening, Mars and Mercury the dawn.
By Fred Schaaf

It's Dwarf-Planet Summer
As Dawn and New Horizons watch Ceres and Pluto, you can too.
By Alan MacRobert

Small Sagittarius Star Cloud
The Sagittarius Milky Way is host to dark nebulae and open clusters.
By Sue French

Table of Contents
See what else July's issue has to offer.

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Categories: Astronomy Headlines

Tour June’s Sky: An Epic Planet Pairing

4 hours 38 min ago

Watch as the two brightest planets — Venus and Jupiter — edge closer together and culminate on June 30th with a dramatically close pairing.

Moon-Venus-Jupiter_June20

A crescent Moon joins the dramatic pairing of Venus and Jupiter on June 20th.
Sky & Telescope diagram

This month features a beautiful pairing of planets in the evening sky. Night by night, Venus and Jupiter inch closer together. Late in the month the pairing gets even more dramatic. They’ll look like a brilliant double star in the sky. The performance culminates on June 30th, when Venus and Jupiter are separated by only 0.3°.

Meanwhile, a third bright planet, Saturn, is taking the stage over in the east. Saturn was at opposition, opposite the Sun in the sky, on May 22nd. So throughout June, instead of rising when the Sun sets, it’ll be a little higher above the southeastern horizon at nightfall.

There's lots more to see by eye in the June evening sky. To get a personally guided tour — and to learn the meaning of the star names Zubeneschamali and Zubenelgenubi — download our 7-minute-long stargazing podcast below.

There's no better guide to what's going on in nighttime sky than the June issue of Sky & Telescope magazine.

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Categories: Astronomy Headlines

Product Videos

5 hours 5 min ago

Dennis di Cicco Welcome to Sky & Telescope’s product videos. Over the past few years, former S&T senior editor Dennis di Cicco has interviewed many manufacturers and vendors of astronomy equipment in an effort to bring their products to life in a way that you will find useful. We hope you enjoy them.

Apogee Imaging Systems — April 2014

Apogee Imaging Systems — October 2012

Apogee Imaging Systems — April 2011

Apogee Imaging Systems — April 2010

Apogee Imaging Systems — April 2009

Astro Haven Enterprises — November 2011

Astro-Physics — April 2013

Astro-Physics — October 2009

ASA Astrosysteme Austria — November 2011

ASA Astrosysteme Austria — October 2009

Celestron — October 2009

Celestron — April 2009

Ceravolo Optical Systems — October 2009

DC3 Dreams — November 2011

DC3 Dreams — October 2009

Explore Scientific — April 2011

Explore Scientific — April 2009

Finger Lakes Instrumentation — April 2014

Finger Lakes Instrumentation — April 2011

iOptron — April 2015

iOptron — April 2014

iOptron — April 2012

iOptron — April 2009

Meade Instruments — April 2012

Meade Instruments — November 2011

Meade Instruments — April 2010

Optec, Inc. — November 2011

PlaneWave Instruments — October 2013

PlaneWave Instruments — November 2011

PlaneWave Instruments — October 2009

PlaneWave Professional Services — October 2013

RSpec — April 2011

Santa Barbara Instrument Group (SBIG) — April 2014

Santa Barbara Instrument Group (SBIG) — April 2012

Santa Barbara Instrument Group (SBIG) — April 2011

Sky-Watcher USA — April 2015

Sky-Watcher USA — April 2014

Software Bisque — April 2015

Southern Stars — April 2013

Stellarvue — April 2014

Tele Vue Optics — April 2014

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Categories: Astronomy Headlines

Most Luminous Galaxy

Wed, 05/27/2015 - 13:48
Most Luminous Galaxy

An artist's depiction of the most luminous galaxy, from NASA / JPL - Caltech

Researchers using NASA’s Wide-Field Infrared Survey Explorer (WISE) have discovered the most luminous galaxy to date. Dubbed WISE J224607.57-052635.0, this Extremely Luminous Infrared Galaxy (ELIRG) shines brighter in the infrared than 300 trillion suns and has an exceptionally supermassive black hole at its core. The sheer size of this black hole-gargantua is one of a few such entities that leave astronomers scratching their heads as to how in the world (or in this case, the universe) such giants can grow so big so quickly. We still don’t quite know the answer, but astronomers have a few ideas.

One idea involves the collapse of the universe’s earliest stars. Made only of hydrogen, helium, and some other Big Bang leftovers, these stars initially contained no heavier elements.  With no way to cool down the heat of gravitational collapse, they were able to grow much bigger than the metal-rich stars of today’s universe. Thus, when these early stars ended their short lives, the black holes they created were easily hundreds of times the mass of the Sun, much bigger than today’s stellar mass black holes. And after collapsing, the black holes grew even bigger by gobbling up nearby matter.

All of this, however, still takes a long time — too long, some astronomers believe, to have built black holes as massive as some of those found within ELIRGs.

Another theory postulates that primordial gas might have seeded biggies like WISE J224607. In this model, instead of a star forming, growing, and collapsing, gas clouds in the early universe collapsed directly into black holes. These black holes would not only be at least 10 times more massive than star-seeded black holes, but they would also have had more time to gobble and grow.

The researchers who discovered WISE J224607 are exploring other properties that might have helped the black hole grow so big so fast, such as chaotic accretion that hid its own radiation. But we’ll have to study it, and other ELIRGs, much more before we can fully understand their founding histories.

See more information on WISE J224607.57-052635.0 in the JPL press release.

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Categories: Astronomy Headlines

Argimusco – The old rocky man

Wed, 05/27/2015 - 13:19

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Categories: Astronomy Headlines

NEAF 2015 Product Videos Are Here!

Wed, 05/27/2015 - 12:45
NEAF scene

Courtesy Rockland Astronomy Club

As amateur astronomers gathered several weeks ago at the 24th annual Northeast Astronomy Forum, they caught first glimpses of hot new products showcased at one of the world's largest astronomy trade shows.

Now you can too, whether you made it to NEAF or not. Former S&T editor Dennis di Cicco interviewed three vendors about their newest products at the show. Watch these in-depth conversations to find full details on new product lines and featured equipment.

Product Videos

Video Interview with iOptron

Video Interview with Sky-Watcher USA

Video Interview with Software Bisque

See our entire library of video interviews.

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Categories: Astronomy Headlines

VIDEO: iOptron at NEAF 2015

Wed, 05/27/2015 - 12:37

ioptroniOptron’s chief engineer Kevin Zou takes Dennis di Cicco on a tour of the company’s extensive line of telescope mounts and camera tracking platforms.

 

See more videos from vendors at NEAF 2015.

Return to our Product Videos page.

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Categories: Astronomy Headlines

VIDEO: Sky-Watcher U.S.A. at NEAF 2015

Wed, 05/27/2015 - 12:35

Sky-WatcherUSA_logo_WSky-Watcher product specialist Kevin LeGore gives Dennis di Cicco an overview of the company’s latest offering of telescopes, including the new Quattro line of Newtonian astrographs. Also covered are two new large-aperture Maksutov systems, one a Mak Cassegrain and the other a Mak Newtonian, as well as the Sky Watcher line of Dobsonian reflectors.

 

See more videos from vendors at NEAF 2015.

Return to our Product Videos page.

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Categories: Astronomy Headlines

VIDEO: Software Bisque at NEAF 2015

Wed, 05/27/2015 - 12:34

Software-Bisque-LogoDennis di Cicco talks with Stephen Bisque, the founder, president, and CEO of Software Bisque, about the company’s history from its introduction of TheSky planetarium software in the 1980s through its evolution of state-of-the-art robotic telescope mounts. Special attention is given to the latest generation of mounts, including the flagship Paramount ME II, Paramount MX+, and the brand new Paramount MyT.

See more videos from vendors at NEAF 2015.

Return to our Product Videos page.

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Categories: Astronomy Headlines

Migrating Stars in 47 Tucanae Cluster

Wed, 05/27/2015 - 09:24

Observations of white dwarfs in a densely populated globular cluster confirm astronomers’ expectations that stars migrate to a cluster’s outskirts after losing weight.

Globular Cluster 47 Tucanae

Globular Cluster 47 Tucanae, from the Hubble Space Telescope

Gravity has everything to do with the way stars interact with one another, and the stars in globular clusters are no exception. Globular clusters are groups of very old stars bound together in a sphere. They organize their stars by mass, with heavier, slower stars congregated near the middle, and lighter, faster ones at the cluster’s edge.

Dynamical relaxation is the process by which clusters organize themselves in this way, and it is also the process that reorganizes stars when any mass changes occur. Some stars do not have static mass, and when they lose weight, the gravity in the cluster will propel them outward.

White dwarfs are one type of low-mass star that is found in the outer reaches of a cluster. They began as the cores of stars like the Sun. When the stars hit the end of their fusion-powered lives, they shrug off their outer layers to reveal the collapsed, planet-size core at their hearts. The process by which a star reaches this white dwarf stage causes it to lose a large portion of its mass — about 40%—in the form of stellar winds.

Before losing this mass, the star is situated near the center of the cluster alongside other massive objects. But then, after becoming a smaller white dwarf, it migrates to a new position via gravitational interactions with other stars, that is relative to its new weight. This mass-loss process and movement makes white dwarfs a great subject for observing dynamical relaxation, yet until now we haven’t caught this migration in action.

Using Hubble’s Wide Field Camera 3 — which has the ability to catch ultraviolet light that is dispersed by Earth’s atmosphere and therefore invisible to ground-based telescopes —  Dr. Jeremy Heyl (University of British Columbia, Canada) and colleagues studied white dwarf stars in the globular cluster 47 Tucanae.

This cluster is a rich agglomeration of stars in the Southern Hemisphere sky and a frequent research target, but it hasn’t been analyzed in this particular way before. Because white dwarfs cool as they age, and because hotter (younger) white dwarfs are brighter in ultraviolet wavelengths than cooler (older) ones, the researchers were able to estimate the ages of the cluster’s stars and identify two major populations of white dwarfs.

One population was a group of relatively new white dwarfs, only a few million years old, and the other a very old, 100 million-year-old group. Heyl and colleagues examined the location of the stars in each age category and found that the younger ones were gathered near the center of the cluster, while the older ones were dispersed at the outer edges.

This result is just what they expected to find.

Since stars expel the most mass in the stage immediately prior to becoming a white dwarf (the so-called asymptotic giant branch, or AGB, stage), it follows that those stars that recently became white dwarfs would still be hanging around the center of the cluster, not having had time to begin their migration outward. Similarly, older stars that had more time as smaller entities should have already arrived at their destinations.  This observation confirmed not only the presence of dynamical relaxation, but also the theory that stars do indeed lose most of their mass in their AGB phase.

The team didn’t determine whether the white dwarfs also show signs of dynamical relaxation in their motions, but that will be a good focus for follow-up. For now, the analysis is a nice confirmation of what we thought we knew about the mechanics within globular clusters.

 

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Categories: Astronomy Headlines

Will We Still Recognize the Sky in 27,800 AD?

Wed, 05/27/2015 - 05:40

With Arcturus as our touchstone, we set off in a virtual time machine to visit the sky of the distant future.

Dazzling and dizzying fast

Arcturus, an orange giant star, is the 4th brightest in the night sky and exhibits the largest proper motion of any first magnitude star except for Alpha Centauri.
Greg Parker

Bright orange Arcturus twinkles high in the southeastern sky at dusk this week. Its slow climb from the northeastern horizon every March heralds the arrival of spring. Earth's revolution around the Sun ensures that Arcturus follows a familiar path year after year.

But hidden within in its apparent motion across the sky is Arcturus's own intrinsic or proper motion of 2.3″ to the southwest (PA 209°) each year. This very tiny amount amounts to just 1/800 the diameter of the Full Moon. Even over an 80-year lifetime you'd never notice the star's movement with the naked eye. That's why we have telescopes.

Over time, those arcseconds add up. If you were to make a careful drawing or take a photograph of the star when you were 20 years old and then redraw its position say 40 years later, Arcturus would have moved 92″ or about 1/20 the Moon's diameter, a distance obvious even at low magnification. Advice to young readers: get crackin'!

Big orange on a roll

As we expand the time scale, Arcturus' motion to the southwest becomes obvious as it "stretches" the outline of Boötes. Edmund Halley was the first to notice that Arcturus had moved compared to positions recorded by the ancient astronomers Hipparchus and Ptolemy.
Chris Marriott's SkyMap

Arcturus stands out among its fellow stars because it's moving rapidly in relation to the Sun as well as perpendicular to the galactic plane in which the Sun revolves. I've included a map showing its gradual drift southward at the breathtaking velocity of 122 km/s (the Sun travels at 30 km/s).

Patience required!

Despite its rapid speed, seeing Arcturus move across the sky takes a telescope and a good part of a lifetime. Stars are labeled with magnitudes; scale at lower right ticks off 10′. The dashed blue lines connecting Arcturus to the two field stars will help you gauge its movement. The line goes from "bent" to straight between 2015 and 2065. Click for a larger version.
Chris Marriott's SkyMap

I like to imagine taking an after-dinner stroll with the Greek astronomer Hipparchus, who lived in the 2nd century BC. Among his many accomplishments were the compilation of the first detailed star catalog and the invention of the magnitude system to quantify star brightness. Keen observer that he was, I've no doubt he'd notice something amiss with the outline of Boötes with Arcturus having moved 1.2° southwest since his time.

Round and round and round

Precession of Earth's axis causes it to describe a circle in the sky like a toy top on its side.
NASA

I've always loved time travel ever since seeing the movie The Time Machine as a kid. Astronomers using telescopes on the ground and in space (the Hipparcos satellite, of course!) have now measured the proper motions of many stars. Incorporated into commonly available software programs like Stellarium, The Sky, and others, they let us see the skies of the past, present, and future with a few clicks of the mouse.

Care to jump in my time machine for a look at what's ahead? I've chosen the year 27,800 AD because that's when precession of the Earth's axis will return Polaris to its seat near the North Celestial Pole. Precession, caused by torque produced by the Sun's and Moon's gravity on Earth's equatorial bulge, causes our spin axis to describe a circle in the sky with a period of about 26,000 years. In 3000 BC it pointed at Thuban in Draco;12,000 years from now Vega will reign as polestar.

Constellations shift shape only slowly but given a precessional kick in the pants, we'd notice striking changes in 26,000 years. More distant stars like Spica will have budged just a little, while Arcturus and others practically leap across the sky.

Back to the Future

A weirdly distorted sky (for us) will be the norm for our distant descendants. A few, like the head of Scorpius and Libra, change little. Click for larger version.
Stellarium

Brief return to the present

The current sky facing south around midnight in late May. A close comparison shows many changes in star positions between now and the next precession cycle. Click for larger version.
Stellarium

Overall, much of the sky would still look familiar, but with lots of Dali-esque twisting and stretching. Good examples of slightly mangled groups include Ursa Minor, Bootes, Virgo, and the Big Dipper asterism. Others like Cassiopeia might go unrecognized were it not for it location near figures less altered by time.

Crazy Cassiopeia

North offers a mix of the familiar and unfamiliar in the distant year of 27,800. Click for a larger version.
Stellarium

Star distances and hence magnitudes will likewise have changed. Arcturus is closest to Earth now but will be farther and fainter in the year 27,800.

I hope your enjoyed our brief foray into the future. Stop back next week, when I'll provide maps and details on finding and tracking two special stars that move so fast, you'll only need a year or two to catch them at their game.

Need to know what the sky looks like right now? The Sky & Telescope planisphere will show you what's up!

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Categories: Astronomy Headlines

Sundog in wispy clouds

Mon, 05/25/2015 - 14:29

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Categories: Astronomy Headlines

NGC6940 and NGC6939 Widefield

Mon, 05/25/2015 - 11:27

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Categories: Astronomy Headlines

M104

Mon, 05/25/2015 - 10:24

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Categories: Astronomy Headlines

M51 HaRGB

Mon, 05/25/2015 - 10:11

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Categories: Astronomy Headlines

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