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Inside the February 2015 Issue

Fri, 12/19/2014 - 13:57
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FC_Feb15_172-pxAstronomy On All Scales: From Minor Moons To Cosmic Voids

This month's cover story issues an observing challenge: find the solar system's minor moons in your scope, such as Mars's potato-shaped satellites or even the faint Uranian moon Miranda. And when the nights are cloudy, or just too cold, step inside to read about cosmic voids (though the enormity of their emptiness might make you shiver). Author Marcus Woo takes us on a journey to these vast expanses, explaining their existence and what they could tell us about dark energy, dark matter, and the fate of the universe. And if voids aren't enough to send chills down your spine, turn the page to read about astronomy's influence over horror writer and amateur astronomer H.P. Lovecraft. Plus, find all the usual goodies, including our February sky chart and Jupiter tables, deep-sky treasures in Canis Major and Minor, and scope-aligning techniques.

Feature ArticlesPhobos

Phobos, Mars's larger (but still minor) moon.
NASA / JPL / Malin Space Science Systems

Into the Void
The emptiest spaces of the universe may hold clues to cosmic mysteries.
By Marcus Woo

Observing Minor Moons
Look for some of the solar system's more challenging objects.
By Terry N. Trees

Cosmic Dread
The astronomy of H. P. Lovecraft.
By John Franch & Alan MacRobert

Aligning Go To Mounts
Get the most out of your computerized scope with these helpful tips.
By Rod Mollise

Astrophotography Today
Advanced imagers define the trends of the 21st century.
By Sean Walker

Beyond the Printed PageFig1_Bolshoi1_480px

Computer-simulated large-scale structure — and voids
Stefan Gottlieb / Leibniz-Institut FüAstrophysik Potsdam

Fly Through Cosmic Voids by Monica Young
Soar through the universe, both theoretical and observed.

Mutual Events Among Jupiter's Moons
Find out how to watch Jovian moons eclipse and occult one another.

Astronomical League Sketching Award
Improve your observing skills by bringing pencil and paper to the eyepiece.

Lunar Librations by Sean Walker
Librations and other lunar data for January 2015.

ALSO IN THIS ISSUEMars-by-Rick-Schrantz_5-7-2014

Rick Schrantz

Another Close One
Venus and Mars come together for a study in contrasts.
By Fred Schaaf

Going to the Dogs
Spend an evening with our canine companions.
By Sue French

A Simple Homebuilt Focuser
This inexpensive focuser doesn't require a machine shop to build
By Gary Seronik

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

The post Inside the February 2015 Issue appeared first on Sky & Telescope.

Categories: Astronomy Headlines

This Week’s Sky at a Glance, December 19 – 27

Fri, 12/19/2014 - 13:25
Some daily sky sights among the ever-changing Moon, planets, and stars.

Friday, December 19

Have you ever tried to catch Sirius actually rising? If you can find a good view down to the east-southeast horizon, watch for Sirius emerging about two fists at arm's length below Orion's Belt. It now rises sometime around 7:30 or 8 p.m. local time, depending on your location. When a star is very low, it tends to twinkle quite slowly and often in vivid colors. Sirius is bright enough to show these effects well.

Moon and Saturn at dawn, Dec. 20, 2014

The waning Moon on the morning of Saturday the 20th is only a day and a half from new. This is the view about 45 minutes before sunrise (exact for the middle of North America).

In early dawn Saturday morning, see if you can spot Saturn and the waning Moon low in the southeast, as shown here. The best time is probably about 60 minutes before sunrise, depending on clouds and atmosphere.

Saturday, December 20

You are remembered, Carl Sagan (November 9, 1934 – December 20, 1996).

Two deep mutual eclipses happen among Jupiter's moons! Callisto will cast its shadow onto Io from 10:13 to 10:32 p.m. Eastern Standard Time, then it will do so again from from 6:49 to 7:12 a.m. Sunday morning EST (3:49 to 4:12 a.m. Sunday morning PST). At mid-eclipse in both cases, Io should dim by a very noticeable 1.1 magnitude. Compare it carefully with the brightnesseses of Jupiter's other moons.

For the first of these eclipses, Io will appear just to Jupiter's east quite close to Ganymede, which is normally only 0.4 magnitude brighter. Dimmer Callisto will be farther east. The timing is excellent for observers in Europe, though you'll have to go out very late; add 5 hours to the times above to get UT. The timing is fair for North America's East Coast, where Jupiter will be rather low in the east. Westerners miss this one.

For the second eclipse, Jupiter will be high in the dark for the western half of North America. Callisto, Io, and Ganymede will be more evenly spaced east of Jupiter, with Io in the middle.

Sunday, December 21

The solstice occurs at 6:03 p.m. EST, when the Sun reaches its farthest point south for the year and begins its six-month return northward. This is the longest night and the start of winter in the Northern Hemisphere; the longest day and the start of summer in the Southern Hemisphere. Happy Yule!

New Moon (exact at 8:36 p.m. EST).

Monday, December 22

Shortly after sunset, look for the hairline crescent Moon to the right of Venus (from North America). This is a challenging observation; bring binoculars.

Moon, Mars and Venus at dusk, Dec. 23-25, 2014

Back in the evening sky, the Moon now waxes past Venus and Mars.

Tuesday, December 23

Now the crescent Moon is much easier to see in twilight. Spot Venus below it, as shown here.

Maybe you're familiar with the ET Cluster, NGC 457 in Cassiopeia. But what about its neighbor Sharpless 2-173, a faint nebula containing the weak cluster Mayer 1? Use the Queen's Kite asterism to get there, as Sue French shows in her Deep-Sky Wonders chart and column in the December Sky & Telescope, page 56.

Wednesday, December 24

Tiny Mars in twilight glimmers to the left of the increasingly thick crescent Moon, as shown here.

Thursday, December 25

Now Mars is far below the Moon at dusk.

Got a first telescope for Christmas? Know someone who did? Some advice: What to See with Your New Telescope.

Friday, December 26

This is the time of year when Orion shines in the east-southeast after dinnertime. He's well up now, but his three-star Belt is still nearly vertical. The Belt points up toward Aldebaran and, even higher, the Pleiades. In the other direction, it points down to where bright Sirius is about to rise.

Saturday, December 27

The Moon is almost first-quarter this evening. Look to its upper right after dinnertime for the Great Square of Pegasus again balancing on one corner.

Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby; for an easy-to-use constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential guide to astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

Pocket Sky Atlas

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but it's still less than one per square degree on the sky. Also plotted are many hundreds of telescopic galaxies, star clusters, and nebulae.

Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of charts). The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and once you know your way around, the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope.

You'll also want a good deep-sky guidebook, such as Sue French's Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

Can a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability, which means fairly heavy and expensive). As Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."

This Week's Planet Roundup

Mercury is buried in the sunset.

Venus (magnitude –3.9) is beginning to show through the glow of sunset. Look for it just above the southwest horizon 20 or 30 minutes after sundown. The farther south you live, the higher it will appear.

Mars (magnitude +1.1, in central Capricornus) still glows in the southwest during and after twilight. And it still sets around 8 p.m.

Jupiter (magnitude –2.4, in western Leo) rises in the east-northeast around 9 p.m. About 45 minutes later, fainter Regulus (magnitude +1.4) rises below it. By dawn they shine in the west-southwest — with Regulus now to Jupiter's upper left.

Saturn (magnitude +0.5, between Libra and Scorpius) glows fairly low in the southeast before and during dawn. Look for it far below Arcturus. Late in the week, use binoculars to start looking for Antares twinkling way under Saturn as dawn grows bright.

Uranus (magnitude 5.8, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are in the south and southwest, respectively, right after dark. Use binoculars or a small telescope and our finder charts for Uranus and Neptune.

__________________________

All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America.

Eastern Standard Time (EST) is Universal Time (UT, UTC, or GMT) minus 5 hours.

"Imagination will often carry us to worlds that never were. But without it we go nowhere."

— Carl Sagan

The post This Week’s Sky at a Glance, December 19 – 27 appeared first on Sky & Telescope.

Categories: Astronomy Headlines

Sky & Telescope’s New Telescope-Tutorial Videos

Fri, 12/19/2014 - 07:16

In a quartet of high-quality videos, Sky & Telescope editors offer newcomers solid, objective tips on how to buy, use, equip, and care for new telescopes.

My first telescope showed up as a colorfully-wrapped package — too big to be a baseball bat — underneath the family Christmas tree. My parents did their best to get me a good one, but truthfully it was a pretty modest affair purchased at the local Sears. Still, it was a doorway to the universe, the most prized possession of a star-struck 10-year-old boy growing up in Central California.

These days, first-time telescope purchasers are confronted with a bewildering array of choices: Dobs, Maks, Newts, APOs, SCTs, GoTos, Push-Tos, and more. How can a newbie hope to make a sensible choice? The truth is: buying a telescope is like buying a car. No single model is right for everyone, and it helps to have a seasoned, trusted friend help you pick the right one.

That's why the editors of Sky & Telescope decided to produce a series of how-to videos about buying and using telescopes. Of course, lots of websites and personal blogs offer this kind of advice, but the well-produced videos in our new "Skywatching Series" are unique.

S&T Skywatcher Series video

Kelly Beatty (at left) and Dean Regas offer telescope-buying tips.
Sky & Telescope

The story begins last summer, when I partnered with S&T contributing editor Dean Regas (well known as the cohost of the popular PBS show Star Gazers) to create these videos. I journeyed to Cincinnati, Dean's home turf, where F+W Media maintains a professional video-production facility. Together with chief videographer Rick Deliantoni and his crew, we spent three days writing scripts, hauling equipment in and out of the studio, taking and retaking shots to show the best techniques, and generally having a blast doing it.

I also was introduced to the quirky local delicacy known as Cincinnati chili — but that's a story for another time.

In any case, those four telescope-tutorial videos are now available, and I hope you'll find them both useful and entertaining. Each can stand on its own, but all four togther provide a thorough overview of the equipment that beginning amateurs will encounter on their own astronomical adventures. Here's a recap of each:

Buying Your First Telescope
To make sure you get the telescope that's right for you, this 50-minute video cuts through all the sales hype and shows you what you need to buy with confidence. It explores the basics of telescope optics, different types of mounts, and how to spot quality features that will ensure great nights of stargazing for years to come.

A Guide To Using Your Telescope
Lots of first-time telescope owners become quickly frustrated with the scope's confusing controls and often-inadequate user manual. But it doesn't have to be that way. This 37-minute video is designed to help you get the most out of your scope. It covers key adjustments to make before you head outside, how to point your telescope with confidence, tips on using the right magnification, and how to set up and use a "go-to" mount.

Care and Cleaning of Your Telescope Optics
Even the simplest telescopes need a little TLC once in a while, and this 50-minute video provides the dos and don'ts of telescope care — including the proper techniques for cleaning lenses and mirrors when it's called for. You'll learn proven techniques for everything from basic adjustments to collimating your mirrors to correcting a shaky mount.

Accessories for Your Telescope
Even newbies can benefit from having some quality accessories to enhance nighttime observing, and the astronomical marketplace is full of nifty items that make excellent additions to your skywatching arsenal. This 32-minute video covers a wide array of options such as eyepieces, star charts, filters, dew prevention, and much more.

I always tell newcomers that astronomy doesn't have to have to be hard. With a little guidance, you can gain familiarly with the night sky and effortlessly move your telescope from one celestial treat to the next. Dean and I hope these videos will help make your telescope a door to the universe.

The post Sky & Telescope’s New Telescope-Tutorial Videos appeared first on Sky & Telescope.

Categories: Astronomy Headlines

Curiosity Finds Methane, Other Organics

Wed, 12/17/2014 - 12:46

NASA’s Curiosity rover has detected both methane in Mars’s atmosphere and carbon-bearing organic compounds in its rocks.

On December 16th, team members with NASA’s Mars Science Laboratory reported that the Curiosity rover has confirmed the presence of methane and other organic compounds on Mars. But it’s unclear where these molecules come from — or whether there’s any biological connection.

methane creation possibilities on Mars

There are several ways to add methane to Mars's atmosphere (and take it away again). Although microbes are the most exciting possibility, other likely sources include reactions between water and the minerals olivine or pyroxene, or solar ultraviolet radiation breaking up meteoritic dust on the planet's surface.
NASA / JPL-Caltech / SAM-GSFC / Univ. of Michigan

Organics are molecules made up of carbon atoms linked to other elements, especially combinations of hydrogen, nitrogen, and oxygen. But they don’t automatically signal “life.” Dozens of different organic molecules occur abiotically in interstellar clouds, and they can rain down from space as micrometeoritic dust. Either way, organics would break down fast in the hostile Martian environment, destroyed by solar ultraviolet rays or by the strongly oxidizing soil, so missions have had trouble detecting them.

One simple organic molecule, methane gas (CH4), has a similar story. It can arise abiotically as a product of the breakdown of meteorite-borne organic matter, or from the interaction of water with silicate minerals such as olivine and pyroxene (both present on Mars). On the other hand, it can also come from primitive microbes called methanogens, which produce methane as part of their metabolic processes. (The sub-meter-scale resolution of the Mars Reconnaissance Orbiter’s HiRISE camera has ruled out Martian cows.)

To find signs of past or present life on Mars, scientists would look for both atmospheric methane and organic-bearing rocks. And they’ve found both. “We now have full confidence that there is methane occasionally present in the atmosphere of Mars, and that there are organics preserved in ancient rocks on Mars in certain places,” announced project scientist John Grotzinger (Caltech) in a press conference at the American Geophysical Union meeting in San Francisco.

But the team stresses that they have no idea where these compounds come from. In fact, Grotzinger pointedly noted that neither the discovery of methane nor of organic matter argues that life is or once was present on Mars.

Drilling Martian Rocksorganics on Mars

The organic chemical chlorobenzene appeared at much higher levels in samples from the mudstone Cumberland than in other rock samples taken by Curiosity.
NASA / JPL-Caltech

The organics detection comes from a sample that Curiosity drilled out of a rock called Cumberland on May 19, 2013 (a.k.a. sol 279 of the mission). Notably, Cumberland lies only 2 meters from another sampled rock, John Klein, which that exhibited little to no organics signature, Grotzinger said.

The team picked Cumberland because it’s full of concretions, hard spheres that form as a water-borne sediment is first solidifying into rock. Because they form so early in this process, concretions are good at encapsulating and protecting fragile organic compounds from destruction by radiation or chemical reactions (such as with the oxidizer perchlorate, detected by NASA’s Phoenix lander in 2008.)

Since drilling into Cumberland last year, Curiosity has been munching on the sample with its Sample Analysis at Mars (SAM) experiment, while teams on Earth checked and rechecked its detections and ran parallel tests with clone equipment to weed out potential false alarms. Mission scientists also waited until the rover took a bite out of Confidence Hills at the base of Aeolis Mons this past September. That assay turned up no organic detection — the positive finding was unique to Cumberland.

The compound SAM identified is chlorobenzene (C6H5Cl), which has shown up before but never at the high level seen in the Cumberland mudstone (at least four times the upper levels inferred from previous samples). It’s one of four compounds that are indigenous to Cumberland, said team member Roger Summons (MIT), but it’s unclear whether it’s actually present in the rock as chlorobenzene or as something else, such as benzilic acid (C14H12O3), that’s transformed by SAM’s processing. Summons said he suspects the chlorobenzene indicates the presence of more complex organic carbon.

More Than a Whiff of Methane

Methane has been a point of contention in Mars research for a few decades. Ground- and space-based observations have found hints of methane in the Red Planet’s atmosphere, either as global averages or plumes from discrete sources. But doubts about the interpretation of some of these results have made scientists circumspect. Adding to the debate was Curiosity’s iffy detection last year, which placed an upper limit of 1.3 parts per billion by volume (ppbv) in the atmosphere — so little that some wondered whether it was even there.

methane levels detected by Curiosity

For two months, atmospheric methane levels spiked in Gale crater. This graph shows levels between August 2012 and September 2014.
NASA / JPL-Caltech

But in fact methane is there, the team now says. The find came in late November 2013, right around Thanksgiving. “We were completely surprised, we suddenly saw 5½ ppbv methane,” said Chris Webster (JPL). “It was an Oh My Gosh moment.”

Unlike a brief whiff of methane the rover had caught previously, this one persisted. A week later the level had risen to 7 ppbv; a month later it was still at that level. A fourth test 3 weeks after that detected 9 ppbv. Then 6 weeks later, it had completely disappeared.

The average over the 2-month period is 7.2 + 2.1 ppbv, about 10 times the average atmospheric level, the team reported at AGU and online December 16th in Science.

The signal’s sudden appearance and disappearance, coupled with the low background levels, suggest that the methane came from a small, localized source either within Gale crater (where Curiosity is) or just outside it. Given the wind patterns at the time, it came from the north, said team member Sushil Atreya (University of Michigan, Ann Arbor).

“What this is telling us is that Mars is currently active, that the surface or the subsurface is communicating with the atmosphere,” Atreya said.

Methane created by ultraviolet rays breaking up organic-bearing interplanetary dust on the Martian surface is sufficient to explain the low background levels. But you need something else to explain the spike, Atreya said.

That argues for either a modern source or leakage of ancient methane from a subsurface reservoir. Once created, methane can be stored for billions of years underground, locked in molecular cages of water ice called clathrates. When something destabilizes these molecular cages — say thermal or molecular stresses, or even small impacts — the methane can escape and worm its way through fissures in the rock to the surface, where it enters the atmosphere. Within a few months winds will spread it around the planet.

Curiosity will continuously monitor methane levels to see if it can catch another spurt and follow how it dissipates, Grotzinger said. NASA has also begun coordinating with the Indian Space Research Organisation (ISRO), whose Mars Orbiter Mission is currently orbiting the Red Planet and has the ability to detect methane.

Biotic or Abiotic?

Curiosity really doesn’t have the ability to distinguish between biological and geological sources. It might get lucky if there’s some obvious biochemical structure in a large sample of organics, or if a spurt of methane is strong enough (tens of ppbv) to establish the ratios of carbon’s three isotopes and see if organic processes have enriched one over the other. But Webster warns that such carbon tests are ambiguous and difficult to do, even on Earth.

The team’s focus instead is setting the groundwork for future missions by sampling as many rock types as possible and learning to identify where organics do and do not appear, Grotzinger said. The rocks at Cumberland and John Klein formed in relatively fresh water. On the other hand, the rock sample at Confidence Hills is more complex than what they’ve seen before, containing magnetite, hematite, and maybe sulfates in addition to the clay minerals seen elsewhere. This mixture might be bad for preserving organics. The team plans to do a lot more drilling than what they’ve done in the past, in order to better understand the distribution of minerals and chemicals in the rocks.

 

Reference: Christopher R. Webster et al. “Mars methane detection and variability at Gale crater.” Science. December 16, 2014.

 

Learn more about methane and mysteries of Mars in Sky & Telescope's special issue Mars: Mysteries and Marvels of the Red Planet.

The post Curiosity Finds Methane, Other Organics appeared first on Sky & Telescope.

Categories: Astronomy Headlines

How to See the Orion Nebula in 3D

Wed, 12/17/2014 - 06:23

Add another dimension of viewing to winter's favorite deep sky object, the Great Nebula of Orion.

Nature at its grandest

The Orion Nebula, located in Orion's Sword directly below the familiar Belt, is an enormous stellar nursery 24 light years across located about 1,350 light-years from Earth. Newborn suns within the nebula's dusty folds set dust and gas alike aglow.
HST / NASA / ESA

The Orion Nebula is arguably the centerpiece of the winter sky. This bright, richly-detailed blossom of glowing gas and dust invites repeated observation. How many of us have pointed our telescope or binoculars in its direction five, six, or even ten times a season?

After the planets and Moon, it's the deep sky object to show family and friends, provided we can coax them into the cold.

Faintly visible with the naked eye and revealing a distinct shape in binoculars, a telescope lays bare the nebula's breathtaking whorls of nebulosity that unfurl from the brilliant Trapezium cluster blazing at its core.

Most sky objects appear pasted against a two-dimensional sky because human stereo vision can't sense depth over cosmic distances. Our eyeballs would have to be light years apart to accomplish that feat. But clues to the sky's hidden third dimension are out there. If you've ever watched one of Jupiter's moons cast its shadow on the planet's cloud tops, the sensation of depth is almost visceral.

Simple anatomy of a nebula

Sketch of the Orion Nebula, also known as M42, viewed at low magnification through a 15-inch (37-cm) telescope. We see its basic features including the dark nebulosity nicknamed the Fish's Mouth, the bright quadruple star Theta 1 Orionis, better known as the Trapezium, and the adjacent nebula M43.
Bob King

With a little help, we can sense the depth in the Orion Nebula, too. The easiest place to begin is the thumb of dark nebulosity, nicknamed the Fish's Mouth, located between the bright multiple star, the Trapezium, and adjacent nebula M43 to the north. Through a small telescope the shadowy shape appears opaque, but a larger instrument clearly shows its mottled texture as light from bright nebulosity in the more distant background punches through.

FIsh's Mouth or Dementor?

In this close up image, the spectacular texture of the Fish's Mouth is evident as light from bright nebulosity in the background filters through gaps in the dark veil. The Trapezium, the Orion Nebula's key source of illumination, is seen at center right.
John Chumack

The 3D effect is dramatic on a dark, moonless night using high magnification. The first time I tried this, I spent the next 20 minutes completely absorbed while visually thrashing through a dark forest of nebulosity I never knew existed. When seen in its entirety, the Fish's Mouth looks a lot more like a Dementor in the Harry Potter movies. Creepy, but utterly moving.

Studies of the structure of the Orion Nebula have shown that radiation pressure from the hot, young Trapezium stars has hollowed out the core of the nebula and literally "blown a hole" through the dust and gas, allowing us to peer inside the cloud to stare this clump of fresh-faced suns in the face.

Ruffled sheets in Orion's core

A 3D representation of the folded, glowing surface of the Orion Nebula shows the Trapezium multiple star hovering in a "valley." To the left is a steep "cliff" of nebulosity that faces the stars and fluoresces in their light to form the bright pink, bar-like feature that borders the bright inner or Huygenian Region of the nebula.
C.R. O'Dell and Zheng Wen with addition of Trapezium stars and annotations by the author

Using infrared and visible light observations from the Hubble Space Telescope and ground-based imagery, astrophysicists C.R. O'Dell and Zheng Wen (Rice University) created a 3D model of the inner surface of the hollowed out core of the nebula. Their model shows that the Trapezium stars hover above a wrinkled, shallow "valley" not far from a steep "cliff." Light from the stars ionizes the nebular gases and sets them aglow.  According to research by O'Dell, the visible nebula we see is little more than a popped blister .08 light-years thick on the surface of the Orion Molecular Cloud, a vast complex of nebulae host to ongoing star formation.

Over the cliff into the valley of the stars

When you put some "meat" on the diagram above, you get something like this — a frame from the Orion Nebula fly-through movie based on data from C.R. O'Dell, Zheng Wen, and David Nadeau with additional contributions from Greg Bacon and the American Museum of Natural History / Rose Center for Earth and Space. Tiny, teardrop-shaped objects are "proplyds," or protoplanetary embryos. Click to watch the fly-through.

So what do we see when we put eye to eyepiece? The bright, green-hued Huygenian Region, named after the 17th century astronomer, Christian Huygens, who first studied it in detail, forms the valley's floor. The cliff is the bright bar-like feature southeast of the Trapezium.

Picturing three dimensions with your inner eye

The bright, inner Huygenian Region of M42. The next time you look at the nebula, imagine the dark Fish's Mouth overhanging the bright nebula. The bright bar or "cliff" towers above the Trapezium, which is nestled in a valley of its own creation. The brightest star in the Trapezium, named  Theta 1 Orionis C, is responsible for a large proportion of the nebula's light. It's the most massive of the four and one of the most luminous stars known.
John Chumack

Wishing you happy travels to another dimension of one of the most beautiful objects in the night sky.

Want more nebulae? Let Sue French guide you to more Deep Sky Wonders!

The post How to See the Orion Nebula in 3D appeared first on Sky & Telescope.

Categories: Astronomy Headlines

Universal Smartphone Eyepiece Adapter

Tue, 12/16/2014 - 09:48
iOptron

6F Gill St., Woburn, MA 01801
866-399-4587; www.ioptron.com

iOptron Universal Smartphone AdapteriOptron introduces the Universal Smartphone Eyepiece Adapter ($58). This adjustable clamp-style adapter fits most cell phones, allowing users to take snapshots of the Moon, planets, the Sun (with proper filtering), and even some of the brightest deep-sky objects. Manufactured from CNC-machined aluminum, the unit can accommodate smartphones from 2½ to 3⅛ inches wide. Its innovative triple-leaf design enables users to position the custom 10-mm threaded eyepiece with a 1¼-inch nosepiece as close as possible to the camera lens on a phone to nearly fill the camera's entire field of view.

SkyandTelescope.com's New Product Showcase is a reader service featuring innovative equipment and software of interest to amateur astronomers. The descriptions are based largely on information supplied by the manufacturers or distributors. Sky & Telescope assumes no responsibility for the accuracy of vendors statements. For further information contact the manufacturer or distributor. Announcements should be sent to nps@SkyandTelescope.com. Not all announcements will be listed.

The post Universal Smartphone Eyepiece Adapter appeared first on Sky & Telescope.

Categories: Astronomy Headlines

MAVEN Finds New Particles, Ion Plume

Tue, 12/16/2014 - 09:30

NASA’s MAVEN mission has discovered a new population of particles in Mars’s upper atmosphere. It’s also found a plume of particles escaping from the planet’s poles, confirming atmospheric loss is happening today.

This image shows an artist concept of NASA's Mars Atmosphere and Volatile Evolution (MAVEN)  spacecraft, which reached the Red Planet on September 21, 2014.Lockheed Martin

This image shows an artist concept of NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, which reached the Red Planet on September 21, 2014.
Lockheed Martin

Members of NASA’s MAVEN mission to Mars presented early results from the spacecraft at the American Geophysical Union meeting in San Francisco on December 15th. The craft arrived at the Red Planet in September and so has only been observing for a couple of months — and part of that time has been spent dealing with Comet Siding Spring and a big solar flare, both of which showered particles on Mars’s atmosphere in October.

Although the preliminary results are just that — preliminary — there are some fun facts emerging.

For example, the Solar Wind Ion Analyzer (SWIA) has found that a fraction of solar wind particles manage to dive fairly deep into Mars’s upper atmosphere by playing a chameleon game. The solar wind is charged, made up of ions whizzing through the solar system at a few hundred kilometers per second and carrying with them the solar magnetic field. This solar wind should be deflected around Mars by its ionosphere, the ionized component of its upper atmosphere.

But the team found that about 1⁄500 of the solar wind particles bombarding the Martian atmosphere show up about 200 km above the planet’s surface — less than 1⁄10 the altitude of the ionosphere where they’re normally stymied. Plus, they don’t show up in the region between these two layers. It’s as though they teleport between locations.

solar wind particles at Mars

Solar wind particles measured by MAVEN's SWIA instrument. Black is the typical solar wind energy spectrum, with peaks for hydrogen and helium ions. Blue is from deeper in the ionosphere: the solar wind peaks essentially disappear, as expected. But at even lower altitudes (red), a fraction of the solar wind particles reappear (peak at H+).
MAVEN team

They don’t — although there is an element of poofing into and out of existence involved. SWIA instrument lead Jasper Halekas (University of Iowa) explains that upon arrival, the solar wind particles are likely stealing electrons from the uppermost atmosphere, thereby transforming to neutral particles. Unlike ionized particles, neutrals can pass through the ionosphere and any magnetic fields with impunity. They’re therefore able to drill deep into Mars’s atmosphere, sailing unencumbered until the atmosphere grows denser and there’s more stuff to run into. Then they again do a charge exchange with atmospheric particles, becoming ions again.

This explanation might seem a bit handwavy. But it does match previous theoretical work that suggested a small fraction of the solar wind should make it this low in the atmosphere. Plus, the correspondence between the solar wind and these chameleon particles is just too good, Halekas says. “Whatever the solar wind does, this population follows,” he explains. Velocity, density, energy levels — it all tracks. “And it’s not just close to the solar wind, it’s dead-on the solar wind.”

Using this population of flip-flop solar wind particles, researchers can track what the solar wind is doing high above while the spacecraft is in the atmosphere, giving them an instantaneous look at what’s going on in the solar wind, how much energy it’s dumping into the upper atmosphere, and how the atmosphere responds. That’ll be a huge help with MAVEN’s mission, which is to understand the drivers of atmospheric loss on Mars.

Plumes of Particlesatmospheric escape from Mars

The MAVEN spacecraft has detected a plume of ions escaping from Mars's pole. It's unclear which physical processes trigger the escape.
MAVEN team

Other initial results the team presented include finding that the concentration of various atoms and compounds changes over fairly small ranges in altitude. These changes likely arise because Mars’s atmospheric pressure is so low (1% that at Earth’s sea level). Dust storms can heat the atmosphere, raising it, and as the atmosphere flows over volcanoes and other big topographic features, it can develop waves that propagate upward into the upper atmosphere, where MAVEN is taking observations.

The Suprathermal and Thermal Ion Composition (STATIC) instrument also detected a plume of ions at Mars’s pole, created by ions heated and escaping from the upper atmosphere. Instrument lead Jim McFadden (University of California, Berkeley) compared the effect to a Mohawk hairdo. It’s unclear which of the various processes at work in Mars’s atmosphere is stripping the ions away, but the measurements do confirm that the loss is happening.

You can read more about the MAVEN results in NASA’s press release.

 

Want to know more about Mars? Read up on the latest developments in our understanding of the Red Planet in Sky & Telescope's special issue Mars: Mysteries and Marvels of the Red Planet.

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Categories: Astronomy Headlines

Meteor Showers in 2015

Sun, 12/14/2014 - 04:00

Everyone seems to enjoy the brief and sometimes dazzling streaks of light from meteors, sometimes called "shooting stars." The two best meteor showers in 2015 will be the Perseids in mid-August and the Geminids in mid-December.

Bright Geminid meteor

During the 2004 Geminid meteor shower, Alan Dyer caught a bright fireball with a tripod-mounted digital camera. He used a wide-field, 16-mm lens for a 1-minute exposure at f/2.8 with an ISO setting of 800. Expect to shoot a lot of frames before you get this lucky.
Alan Dyer

If you watch the starry night sky from a dark location, a few times every hour you'll see brief streaks of light from meteors, sometimes called "shooting stars." Derived from the Greek word meteoros (meaning "high in the air"), meteors are bits of interplanetary debris slamming into Earth's upper atmosphere at altitudes of 50 to 75 miles (80 to 120 km).

The particles hitting our atmosphere are not large — typically they're no bigger than big sand grains, and something the size of a pea can create a meteor that's dramatically bright. That's because they strike at 20 to 45 miles per second, and all that kinetic energy is rapidly dissipated by frictional heat. In fact, we see a meteor's streak not because the particle is "burning up," but instead because air molecules along its path become flash-heated to thousands of degrees.

Meteors can occur at any time on any night and appear in any part of the sky. On most nights a half dozen of these sporadic (random) meteors appear hourly.

What is a Meteor Shower?

However, several times each year, Earth encounters a stream of gritty debris left in space by a passing comet, and the result is a meteor shower. You'll notice the difference if you watch the sky for a half hour or so during one of these events: not only do the number of meteors you'll see go up, but also the meteors seem to fly away from a common point in the sky called the radiant. This is a trick of perspective, because all these particles are traveling in parallel — part of a vast but sparse "river of rubble" that's spread all around the comet's orbit.

Plot of meteor brightness

A meteor's brightness, plotted here as it would appear directly overhead at an altitude of 60 miles, depends on its mass and the speed at which it enters the atmosphere. Particles typically range in size from sand grains (upper right) to walnuts (lower left).
M. Campbell-Brown / P. Brown

A shower gets its name from the constellation where this radiant lies — for example, August's well-known Perseid shower has its radiant in Perseus. One notable exception to this rule is the Quadrantid shower, named for the now-defunct constellation Quadrans Muralis. Its radiant lies in the constellation Boötes. In any case, the higher a shower’s radiant, the more meteors it produces all over the sky.

Meteor showers usually peak during the predawn hours on the dates listed below, though they're typically active a few nights before and after the peak date. Note that the rates are for ideal conditions: very dark skies free of moonlight or light pollution, with the radiant nearly overhead. Most likely you'll see somewhat lower rates than those listed. Following the table are specific predictions for each shower's prospects during 2015.

For the best possible viewing experience, find a dark location, make yourself comfortable in a reclining chair, and wear plenty of warm clothing (as appropriate). And for more information on watching and studying meteors, see our article on meteor basics and the other articles in the Meteor section of our website.

Major Meteor Showers in 2015ShowerRadiant and directionMorning of maximumBest hourly rateParentQuadrantid*Draco (NE)Jan. 460-1002003 EH1LyridLyra (E)Apr. 2310-20Thatcher (1861 I)Eta Aquariid*Aquarius (E)May 620-601P/HalleyDelta Aquariid*Aquarius (S)July 292096P/MachholzPerseidPerseus (NE)Aug. 1360-80109P/Swift-TuttleOrionidOrion (SE)Oct. 2210-201P/HalleySouthern TauridTaurus (S)Nov. 510-202P/EnckeLeonidLeo (E)Nov. 1810-2055P/Tempel-TuttleGeminidGemini (S)Dec. 141003200 Phaethon

* Strong moonlight will interfere with these showers.

January 4: The Quadrantids

The year usually starts off with a bang, with the brief but active "Quads" peaking around 2:00 UT on the morning of January 4th. This shower's peak lasts just a few hours and, unfortunately, this year it will be seriously compromised by a nearly full Moon. That's too bad — this shower has occasionally peaked at 200 meteors per hour. The radiant is in northern Boötes, which rises in the northeast about 1 a.m. and climbs higher hour by hour.

April 23: The Lyrids

Prospects are better for April's Lyrid meteor shower. This isn't one of the year's strongest displays, but the Moon is only waxing crescent and so won't offer much competition. As with the Quadrantids, this shower puts on a fairly brief performance, and the counts can sometimes exceed one per minute. But the predicted peak (23:00 UT on April 22nd) comes too early for North America, though those on the East Coast might fare a little better than skywatchers in the Far West. Look for a few meteors per hour emanating from a radiant near the Hercules-Lyra border after darkness falls on the 22nd.

Where to spot Eta Aquariid meteors

Here's the Eta Aquariid's radiant as seen from latitude 30° north (Houston, Cairo, Delhi, Shanghai) 90 minutes before sunrise. Farther north, the radiant is even lower when the sky starts to get light.
Sky & Telescope diagram

May 6: The Eta Aquariids

This annual shower originates from none other than Halley's Comet, and these meteors come in fast — 41 miles (66 km) per second! At its best, under ideal conditions, the Eta Aquariids can deliver a meteor per minute. But that's not the case this year: the shower's radiant (in the Water Jar asterism of Aquarius) rises late for northerners, and by then the sky will be flooded with light from a waning gibbous Moon.

July 28: The Delta Aquariids

You might see this long-lasting shower called the Southern Delta Aquariids, because its radiant is below the celestial equator and thus best seen from the Southern Hemisphere. Delta Aquariids tend to be faint, and this year they'll be ruined by light from a nearly full Moon. So don't count on seeing more than a few of these meteors per hour.

August 13: The Perseids

Perseid meteor

With some perseverance, S&T's Dennis di Cicco captured a Perseid meteor with the Milky Way at left from the historic Stellafane compound atop Breezy Hill in Springfield, Vermont.
Dennis di Cicco

Even casual skywatchers know about the Perseid meteor shower, because it offers up to 60 an hour under pleasant summer skies. According to the International Meteor Organization, the shower's 2015 peak should come between 6:30 and 9:00 UT, which is ideal for North America, and the just-past-new Moon will not be a factor. So start watching on the evening of the 12th as soon as the radiant (near the Double Cluster in Perseus) clears the horizon, and stay up as late as you can. Dynamicist Jérémie Vauballion (IMCCE, Paris) predicts that an additional pulse of activity might come about 12 hours earlier (best for Asia), when a dust trail shed in 1862 by the Perseids' parent comet, 109P/Swift-Tuttle, is expected to pass very close to near Earth. The story of how 19th-century observers realized this shower is an annual event is interesting reading.

October 22: The Orionids

Here's another modest shower due to Halley's Comet. Light from a waxing gibbous Moon will be a nuisance until it sets around 1 a.m. After that, you might glimpse up to 20 meteors per hour from a dark site in the hours before dawn. The shower’s radiant is located above Orion’s bright reddish star Betelgeuse. That's close enough to the celestial equator for observers in both the Northern and Southern hemispheres to enjoy the show.

November 5: The Southern Taurids

Lasting from mid-September to mid-November, this broad, weak display typically produces at most a dozen meteors per hour at its peak. But in 2005 skywatchers were treated to a "Taurid fireball swarm" dominated by bright, slow-moving fireballs from larger-than-average particles — and that kind of display might happen again this year. According to dynamicist David Asher (Armagh Observatory), we should expect bright Taurid meteors and fireballs from about October 29th to November 10th. During this period the Moon's phase wanes from just-past-full gibbous to just shy of new. The shower’s radiant is in western Taurus, along its border with Cetus.

November 18: The Leonids

The Leonid shower's parent comet, 55P/Tempel-Tuttle, tends to create narrow concentrated streams of debris that produced prodigious displays in the late 1990s, when it last swung close to the Sun. Since then the shower's activity has varied from year to year, usually offering little more than a trickle of shooting stars radiating from Leo’s Sickle. The nominal peak should be around 5:00 UT — great timing for North Americans.

How to spot Geminid meteors

The Geminid meteors can flash into view anywhere in the late-night sky when the shower peaks in mid-December. But if you follow their paths back far enough, they all appear to diverge from a point in the constellation Gemini.
Sky & Telescope diagram

December 14: The Geminids

This end-of-the-calendar shower is usually the year’s best, with upward of 100 meteors per hour radiating from a spot near the bright star Castor. For 2015, the thin, waxing crescent Moon won't be a distraction at all. Even better, the Geminid radiant is well up in the sky by 9 p.m. as seen from at mid-northern latitudes. The only downside is that this shower is relatively brief, and its predicted peak falls in mid-afternoon for North Americans. Geminid meteors come from 3200 Phaethon, an asteroid discovered in 1983 that circles the Sun every 3.3 years.

Keep tabs on meteor showers and all the year's other celestial happenings with SkyWatch 2015, available in digital and print editions.

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Categories: Astronomy Headlines

This Week’s Sky at a Glance, December 12 – 20

Fri, 12/12/2014 - 01:05
Some daily sky sights among the ever-changing Moon, planets, and stars.

Friday, December 12

This is the time of year when, around 8 or 9 p.m., Cassiopeia stands very high in the north as a flattened letter M. When will you see it perfectly level? This depends mostly on how far east or west you are in your time zone.

Geminid meteor

A Geminid meteor with a terminal burst plunges down during the shower of December 2004.

Saturday, December 13

The Geminid meteor shower should be at its strongest late tonight and tomorrow night. Bundle up even more warmly than you think you'll need, find a dark, shadowed site with an open view overhead, lie back in a reclining lawn chair, and watch the stars. Be patient. Under a fairly dark sky you may see a meteor every minute or two. The Moon, at last quarter, rises around 11 or midnight depending on your location. See article.

Sunday, December 14

The Geminid meteors late tonight should still be near maximum activity; see above. The Moon rises an hour later than it did last night at your location.

Monday, December 15

Double shadow transit on Jupiter! Both Io and Europa are casting their tiny black shadows onto the face of Jupiter from 1:12 to 2:02 a.m. Tuesday morning Eastern Standard Time (10:12 to 11:02 p.m. Monday evening Pacific Standard Time).

Europa itself starts crossing Jupiter at 1:18 a.m. EST, and Europa starts crossing the disk at 2:15 a.m. EST. For all about the doings on and around Jupiter for amateur telescopes this month, see "Action at Jupiter" in the December Sky & Telescope, page 52.

Algol is near its minimum light this evening, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 10:22 p.m. EST (7:22 p.m. PST). It takes several additional hours to fade and to rebrighten. Comparison-star chart.

Tuesday, December 16 Maybe you're familiar with the ET Cluster, NGC 457 in Cassiopeia. But what about its neighbor Sharpless 2-173, a faint nebula containing the weak cluster Mayer 1? Use the Queen's Kite asterism to get there, as Sue French shows in her Deep-Sky Wonders chart and column in the December Sky & Telescope, page 56.

Moon and Saturn at dawn, Dec. 18 - 20, 2014

The waning Moon guides the way to Saturn in the eastern dawn on Wednesday and Thursday mornings. (Positions are exact for the middle of North America. The Moon is drawn three times actual size.)

Wednesday, December 17

Having trouble spotting Saturn in the dawn? On Thursday morning the 18th the waning Moon points down to the spot, as shown here.

Thursday, December 18

On Friday morning the 19th the Moon hangs closer over Saturn, as shown here.

Algol is near its minimum light for a couple hours centered on 7:12 p.m. EST Thursday evening.

Friday, December 19

Have you ever tried to catch Sirius actually rising? If you can find a good view down to the east-southeast horizon, watch for Sirius emerging about two fists at arm's length below Orion's Belt. It now rises sometime around 7:30 or 8 p.m. local time, depending on your location. When a star is very low, it tends to twinkle quite slowly and often in vivid colors. Sirius is bright enough to show these effects well.

Saturday, December 20

You are remembered, Carl Sagan (November 9, 1934 – December 20, 1996).

A deep mutual eclipse among Jupiter's moons! Callisto will cast its shadow onto Io from 10:13 to 10:32 p.m. Eastern Standard Time. At mid-eclipse, Io should be dimmed by a very noticeable 1.1 magnitude. Compare it carefully with the brightnesses of Jupiter's other moons. Io will appear just to Jupiter's east quite close to Ganymede, which is normally only 0.4 magnitude brighter. Dimmer Callisto will be just a little farther east.

The timing of this is excellent for Europe (though you'll have to observe very late; add 5 hours to the times above to get UT), and fair for North America's East Coast, where Jupiter will be rather low. Westerners miss this one.

________________________________

Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby; for an easy-to-use constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential guide to astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

Pocket Sky Atlas

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but it's still less than one per square degree on the sky. Also plotted are many hundreds of telescopic galaxies, star clusters, and nebulae.

Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of charts). The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and once you know your way around, the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope.

You'll also want a good deep-sky guidebook, such as Sue French's Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

Can a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability, which means fairly heavy and expensive). As Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."

This Week's Planet Roundup

Mercury is hidden in the glare of the Sun.

Venus (magnitude –3.9) is beginning to show through the glow of sunset. Look for it just above the southwest horizon 20 or 30 minutes after sundown. The farther south you live the higher it will appear. See Bob King's Venus Finally Comes Out of Hiding.

Mars (magnitude +1.0, in Capricornus) still glows in the southwest during and after twilight. And it still sets around 8 p.m. local time.

Jupiter (magnitude –2.3, in western Leo) rises in the east-northeast around 9 or 10 p.m. About 40 minutes later, fainter Regulus (magnitude +1.4) rises below it. By dawn they shine high in the southwest — with Regulus now to Jupiter's left.

Saturn (magnitude +0.5, between Libra and Scorpius) is emerging into the dawn sky. During early dawn look for it low in the southeast, far below Arcturus.

Uranus (magnitude 5.8, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are still well up in the southern sky right after dark. Use binoculars or a small telescope and our finder charts for Uranus and Neptune.

__________________________

All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America.

Eastern Standard Time (EST) is Universal Time (UT, UTC, or GMT) minus 5 hours.

"Imagination will often carry us to worlds that never were. But without it we go nowhere."

— Carl Sagan

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Categories: Astronomy Headlines

Binocular Comet Lovejoy Heading Our Way

Thu, 12/11/2014 - 11:48

The latest Comet Lovejoy should reach 5th magnitude in late December and January, when it will be nicely placed high in the dark for your binoculars or telescope. It could even become detectable naked-eye.

Comet Lovejoy, C/2014 Q2, on Nov. 27, 2014

The new Comet Lovejoy, C/2014 Q2, as imaged on November 27th by Gerald Rhemann in Austria using a remotely operated 12-inch f/3.6 astrograph in Namibia. Click image for larger view.

A new Comet Lovejoy, designated C/2014 Q2, is heading our way out of deep space and out of the deep southern sky. It may brighten to 5th magnitude from late December through much of January as it climbs into excellent viewing position for the Northern Hemisphere, high in the dark winter night.

This is Australian amateur Terry Lovejoy's fifth comet discovery. He turned it up at 15th magnitude in Puppis last August, in search images that he took with a wide-field 8-inch scope. It hasn't moved very much since then — it's still in Puppis as of December 11th — but it's hundreds of times brighter now at visual magnitude 6.8, reports David Seargent in Australia. On the 9th "I saw it easily using a pair of 6x35 binoculars," he writes. Using a 4-inch binocular telescope at 25×, he says it was a good 8 arcminutes wide with a strong central condensation and no visible tail.

And it's picking up speed across the sky for a long northward dash.

A Comet of the High Dark

"Comet Q2," as some are calling it, will skim through Columba south of Orion and Lepus from the nights of December 16th through the 26th, brightening all the while, as shown on the finder charts for December and January below and on the print-friendly versions here: December, January. The dates on the charts are in Universal Time, and the ticks are for 0:00 UT.

The comet spends the last few days of December in Lepus at perhaps 6th magnitude, though by then the light of the waxing Moon (at first quarter on the 28th) will start to be an annoyance. On New Year's Eve, a little after January 1st Universal Time, look for the comet just off Lepus's forehead as shown on the charts.

The Moon brightens to become full on January 4th. Most of us won't get a dark moonless view again until early in the evening of January 7th, with the comet now crossing northern Eridanus. That's the same day it passes closest by Earth: at a distance of 0.47 a.u (44 million miles; 70 million km). That's also about when it should start glowing brightest for its best two weeks, as it crosses Taurus and Aries high in early evening.

By then the comet is starting to recede into the distance, but its intrinsic brightness should still be increasing a bit; it doesn't reach perihelion until January 30th, at a rather distant 1.29 a.u. from the Sun. By that date the comet should be starting to fade slightly from Earth's point of view. If February it will continue north between Andromeda and Perseus as it fades further, on its way to passing very close to Polaris late next May when it should again be very faint.

Originally Comet Q2 wasn't expected to become this bright. We're basing these predictions on an analysis by J. P. Navarro Pina in late November using the comet's visual behavior for the previous several weeks. Whether it will continue to brighten on schedule is anybody's guess, but the odds are good; comets that don't come near the Sun are more predictable in their brightnesses than those that do.

Q2 is a very long-period comet, but this is not its first time coming through the inner solar system. On the way in, its path showed an orbital period of roughly 11,500 years. Slight perturbations by the planets during this apparition will alter the orbit a bit, so that it will next return in about 8,000 years.

Finder chart for Comet Lovejoy, C/2014 Q2, during December 2014. The dates are in Universal Time; the ticks are at 0:00 UT (8 p.m. on the previous date Eastern Standard Time).

Finder chart for Comet Lovejoy, C/2014 Q2, during December 2014. The dates are in Universal Time; the ticks are at 0:00 UT (8 p.m. on the previous date Eastern Standard Time). Click here for larger view, or click here for print-friendly black-on-white PDF.

Finder chart for Comet Lovejoy, C/2014 Q2, during January 2015. The dates are in Universal Time; the ticks are at 0:00 UT (8 p.m. on the previous date Eastern Standard Time).

Finder chart for Comet Lovejoy, C/2014 Q2, during January 2015. The dates are in Universal Time; the ticks are at 0:00 UT (8 p.m. on the previous date Eastern Standard Time). Click here for larger view, or click here for print-friendly black-on-white PDF.

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Sirius Colors

Thu, 12/11/2014 - 06:58

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Storms Over the Caribbean

Thu, 12/11/2014 - 06:58

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Autumn Nights

Thu, 12/11/2014 - 06:58

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Mysterious beautiful

Thu, 12/11/2014 - 06:58

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NGC 694, 691, 680, 678

Thu, 12/11/2014 - 06:58

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NGC7640

Thu, 12/11/2014 - 06:58

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Melotte 15

Thu, 12/11/2014 - 06:58

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Jupiter in good seeing

Thu, 12/11/2014 - 06:58

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