Jika anda ternampak muka saya tengah TT (Teh Tarik) ni, bermakna anda telah selamat mengharungi 3 hari bumi tak jadi bergelap, dan tarikh 21hb Dis yang penuh tragis dan huru-hara (kononlah).

:-D

Nak ceritanya, Falak Online telah pun berpindah rumah. Bermula sekarang silalah kemaskini link ke WWW.FALAKONLINE.NET ,  tak perlulah letak apa-apa selepas tu, kerana ia akan redirect ke muka hadapan BARU yang sepatutnya.

Laman lama (yang anda lihat sekarang ni), InsyaAllah akan kekal untuk beberapa bulan mendatang. Ia akan menyenaraikan KESEMUA artikel lama saya di FO, bagi rujukan anda semua. Maka, kalau anda nak masih nak marah-marah kat saya berkenaan artikel "3 hari bergelap tu" , masih boleh berbuat demikian, saya terima dengan hati terbuka! :-)

Apa pun, InsyaAllah 2013 mendatang akan terdapat beberapa pembaharuan yang saya dan rakan-rakan Personaliti Astronomi lain usahakan, demi kemajuan bidang Astronomi di Malaysia.

Jom dan Selamat Datang Ke Tahun Baru 2013. 

Jemput masuk --->  WWW.FALAKONLINE.NET

 

Astronomy

...lagi foto komet tu sedang melintasi Marikh..

Facebook - Sun, 19/10/2014 - 20:13
...lagi foto komet tu sedang melintasi Marikh..


cometa C/2013 A1 Siding Spring
la cometa poche ore fa quando si trovava a circa 1,7 milioni di km dal pianeta Marte http://www.astrobin.com/129715/
Categories: Astronomy

Lagi foto Comet Siding Spring bersama Marikh...

Facebook - Sun, 19/10/2014 - 20:00
Lagi foto Comet Siding Spring bersama Marikh...


Gambar-gambar dari kiriman Peter Lake di CIOC_SidingSpring
A quick JPG of tonights close approach. More to come...
Categories: Astronomy

Comet Siding Spring sedang menghampiri Marikh sekarang! Ce tengok. Yang terang t...

Facebook - Sun, 19/10/2014 - 19:57
Comet Siding Spring sedang menghampiri Marikh sekarang! Ce tengok. Yang terang tu Marikh, yang betul2 kat tengah2 frame kecik gedemik yg samar-samar tu.. itulah Comet Siding Spring.

Nota: Komet ini TIDAK BOLEH DILIHAT DENGAN MATA KASAR, kerana ia amat kelam.


Gambar-gambar dari kiriman Nick Howes di CIOC_SidingSpring
Okay folks, we're running... SSO/Tzec Muan Foundation Telescope Takahashi E180/ 20s exposure/ Canon EOS7D at ISO800. Taken at 10:00 UT. We're running on that E180 and the FSQ, more images as they come in. This is RAW unprocessed
Categories: Astronomy

4 Things to Know About the Next Solar Eclipse

Sky and Telescope - Sat, 18/10/2014 - 03:33
What is a partial solar eclipse?

A partial solar eclipse occurs when the Moon covers only part of the Sun as seen from Earth. Because the Sun's disk is never fully covered, you will need protective eye gear at all times if you want to view the Sun directly. Another option is to view the eclipse through a pinhole projection.
Read more about viewing the Sun safely.

When is the next partial solar eclipse going to happen?

Greatest eclipse occurs on October 23, 2014 at 21:44:31 UT.

To find the precise start and end times calculated for your location, visit NASA's Eclipse website.

Where's the best place to watch the eclipse?

The farther north and west you are, the deeper the partial eclipse will become. Credit: Jay Anderson

The farther west and north in North America you are, the better. The American West will see the entire eclipse while the Sun is still high in the afternoon sky. Further east, the eclipse will be in progress at sunset, affording some potentially dramatic views if you have access to a clear western horizon. New England will miss all the action. In addition to going west, you'll see a deeper eclipse at more northern latitudes.

When's the next solar eclipse?

This is the last eclipse of the year. The next total solar eclipse is March 20, 2014, though the path of totality only comes near Svalbard, Norway, an archipelago in the Arctic Ocean. A more easily visible total solar eclipse will occur on March 9, 2016 in Indonesia. America’s next total eclipse of the Sun is on August 21, 2017, when the center of the Moon’s shadow will cross from Oregon to South Carolina.

For more information about the upcoming solar eclipse, see our in-depth article. And come back soon to find out where you can view the eclipse online.

The post 4 Things to Know About the Next Solar Eclipse appeared first on Sky & Telescope.

Categories: Astronomy

This Week’s Sky at a Glance, October 17 – 25

Sky and Telescope - Fri, 17/10/2014 - 17:05
Some daily sky sights among the ever-changing stars and planets

Watch the thinning crescent Moon pass Jupiter and Regulus in early dawn.

Friday, October 17

Before dawn Saturday morning, Jupiter shines above the waning Moon, as shown at right. Although they look rather close together, Jupiter is 2,100 times farther in the background — it's at a distance of 47 light-minutes, compared to the Moon's 1.3 light-seconds.

Saturday, October 18

This is the time of year when, right after nightfall, W-shaped Cassiopeia stands on end halfway up the northeastern sky — and when, off to its left, the dim Little Dipper extends leftward from Polaris in the north.

Sunday, October 19

Today the faint Comet Siding Spring (C/2013 A1) makes its much-awaited close pass by Mars, as told in the September Sky & Telescope, page 53, with chart. This will be an extremely challenging observation photographically, and probably impossible visually, with Mars low in the southwest right at the end of twilight and the comet only about 11th or even 12th magnitude, fainter than originally predicted.

At least you can follow a webcast of the encounter courtesy of the Virtual Telescope project; watch in real time starting at 16:45 UT (12:45 p.m. EDT) today, or watch the recording later. And see our article, Comet Siding Spring Skims Past Mars. NASA's fleet of spacecraft at Mars will carry out observations from their much better vantage point.

Monday, October 20

The annual Orionid meteor shower should be active before dawn's first light this morning and for the next few mornings. The shower's radiant (apparent perspective point of origin) is in the top of Orion's Club, and this is highest before morning twilight begins.

How early in the week can you pick up Mercury in the dawn?

Tuesday, October 21

A challenge observation: as dawn brightens on Wednesday morning the 22nd, binoculars or a telescope may already show Mercury below the thin crescent Moon very low in the east, as shown here. Look about a half hour before sunrise. Mercury is not only low but faint: a tiny crescent only magnitude 2.1. If you succeed, this may be the thinnest you ever see Mercury as a crescent: about 10% sunlit.

Wednesday, October 22

As autumn deepens, the Great Square of Pegasus shines ever higher in the east at nightfall. For now it's still balancing on one corner. Later in the night and the season, it turns to rest upright very high when you face south.

The farther north and west you are, the deeper Thursday afternoon's partial solar eclipse will become. Click to enlarge image. Credit: Jay Anderson

Thursday, October 23

A partial eclipse of the Sun happens this afternoon for most of North America. Seen from the eastern half of the continent, the Sun sets while the partial eclipse is still in progress. Westerners get to see the whole thing. Eastern New England just misses out. See our article online: Partial Solar Eclipse, October 23, 2014. Griffith Observatory in Los Angeles plans a live webcast from 5:00 to 7:45 p.m. Eastern Daylight Time. Also: webcast from Columbus State University in Georgia, 5 p.m. EDT.

Bonus: The huge sunspot AR2192 should be near the middle of the Sun's disk by today.

While we're at it, here's a preview of the great total solar eclipse that will cross the United States diagonally in less than three years: Americans Will See Total Solar Eclipse in 2017.

Friday, October 24

As the stars come out this week, Deneb is nearly straight overhead for skywatchers at mid-northern latitudes. Brighter Vega is west of the zenith. Altair is farther from the zenith toward the south.

Saturday, October 25

A half hour after sunset, spot the thin waxing crescent Moon very low in the west-southwest. Look to its lower right to see if you can still detect Saturn, which has been sinking lower every day. Binoculars help.

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).

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

Giant sunspot: Active Region AR2192 on Monday, October 20th, as it rotates into better view. Courtesy NASA / Solar Dynamics Observatory.

The Sun, update Oct. 20: A big naked-eye sunspot has rotated around the Sun's eastern limb into plain view if you have a safe solar filter to view through. (A "naked-eye" sunspot means that no magnification is needed, not no filter!! See Solar Filter Safety.) Active Region AR2192 is still growing; it has enlarged by 1/3 in just the last day. See more at Spaceweather.com. The spot will be wonderfully presented near the middle of the Sun's disk this Thursday the 23rd during the partial solar eclipse!

Mercury is very dim and low in the dawn for much of the week, but by the 24th or 25th it'll be more readily visible. Look for it above the east-southeast horizon about a half hour before sunrise.

Venus stays hidden in the glare of sunset for another month or so.

Mars (magnitude +0.9) remains low in the southwest during dusk. Use binoculars to took for twinklier orange Antares (magnitude +1.0) ever farther down to Mars's lower right.

Jupiter (magnitude –2.0, at the Cancer-Leo border) rises in the east-northeast around 1 or 2 a.m. It shines brightly high in the east-southeast by dawn. Regulus shines about a fist-width below Jupiter and a bit left.

Saturn (magnitude +0.6, in Libra) is sinking away into the sunset. As twilight fades, use binoculars to look for it far to the right or lower right of Antares — which is far lower right of Mars.

Uranus (magnitude 5.7, in Pisces) and Neptune (magnitude 7.9, in Aquarius) are high in the southeast and south, respectively, by 9 p.m. See our finder charts for Uranus and Neptune online or in the September Sky & Telescope, page 50.

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 Daylight Time (EDT) is Universal Time (UT, UTC, or GMT) minus 4 hours.

“This adventure is made possible by generations of searchers strictly adhering to a simple set of rules. Test ideas by experiments and observations. Build on those ideas that pass the test. Reject the ones that fail. Follow the evidence wherever it leads, and question everything. Accept these terms, and the cosmos is yours.”

— Neil deGrasse Tyson, 2014.

 

The post This Week’s Sky at a Glance, October 17 – 25 appeared first on Sky & Telescope.

Categories: Astronomy

Astronomy-Falak Education Seminar 2014 sedang berlangsung di USM, Pulau Pinang,...

Facebook - Fri, 17/10/2014 - 11:43
Astronomy-Falak Education Seminar 2014 sedang berlangsung di USM, Pulau Pinang, bermula hari ini hingga Ahad.

Jangan lepaskan peluang!

http://astrofalak-edusem.blogspot.com/


SEMINAR PENDIDIKAN ASTRONOMI-FALAK MALAYSIA KALI PERTAMA
astrofalak-edusem.blogspot.com
Categories: Astronomy

Comet Siding Spring Skims Past Mars

Sky and Telescope - Fri, 17/10/2014 - 05:40

Mars has a front-row seat for an extremely close encounter with Comet Siding Spring (C/2013 A1) on October 19th.

Comet Siding Spring passes roughly 85,000 miles from Mars on October 19, 2014.
NASA / JPL / Horizons

History is being made this week: a comet is about to pass closer to a planet (without hitting it) than ever before in recorded human history.

Unfortunately, the planet is not Earth — it's Mars.

On October 19th, at 18:29 Universal Time, Comet Siding Spring (C/2013 A1) is going to pass about 85,000 miles (137,000 km) from the Red Planet — about a third of the Earth-Moon distance. As seen from the Martian surface, the comet will be a huge glowing cloud in the nighttime sky with an estimated total magnitude of about –6.

The dust tail left in C/2013 A1’s wake will miss Mars, but not by much. Still, multiple teams of dynamicists suspect that a few percent of the particles, those with the highest ejection velocities, could strike the planet about 90 to 100 minutes after the nucleus comes closest.

Since those comet crumbs will be arriving at a very fast 35 miles (56 km) per second, even the smallest of them could inflict damage on one or more of the five spacecraft now in orbit around Mars. To avoid this threat, over the past few months NASA engineers have manipulated the trajectories of the agency's spacecraft (Mars Reconnaissance Orbiter, Mars Odyssey, and the just-arrived MAVEN) so that these craft will all be on the opposite side of the planet during the window of greatest danger.

Back here on planet Earth, Mars is still observable low in the southwest after sunset. But the comet is so faint (no brighter than 11th or 12th magnitude) that you'll need a sizable telescope to view it. Fortunately, Italian observer Gianluca Masi has just that. Join his Virtual Telescope Project for online viewing of the comet encounter beginning at 16:45 Universal Time, or 12:45 p.m. EDT, on the 19th.A Deep-Space Visitor

Despite this duck-for-cover caution, planetary scientists are looking forward to the encounter with excitement. This comet is special because it's a first-time visitor to the inner solar system. Its icy nucleus, on the smallish side with an estimated diameter of roughly a half mile (700 meters), has been inbound from the distant Oort Cloud for the past several million years. Never before has it felt the Sun's warmth.

Comet Siding Spring (C/2013 A1) was already quite active in March 2014, when it was still 3.8 astronomical units from the Sun. In this red-light view, taken with the Hubble Space Telescope, the comet's coma is about 20,000 miles (30,000 km) across.
NASA / ESA / J.-Y. Li (Planetary Science Inst.)

When first spotted it on January 3, 2013, it was still very far from the Sun: 7.2 astronomical units (a.u.), or 670,000,000 miles. Credit for the discovery goes to veteran comet-hunter Rob McNaught, who captured it as a 18½-magnitude blip in a series of images taken with the Uppsala Southern Schmidt Telescope at Siding Spring Observatory in Australia. (Tragically, 10 days later a wildfire overran part of the observatory, destroying McNaught's home.)

Most comets don't "turn on" until they get much closer in. But by then the nucleus of C/2013 A1 had already started releasing gas and dust to form a coma. Last June, having cruised to within 2½ a.u. of the Sun, the comet became much more active. By then visible-light images from the Hubble Space Telescope showed multiple jets coming off the nucleus, and infrared views from the Spitzer Space Telescope showed that most of the gas was carbon dioxide.

Click on the frame above to see a NASA animation of Comet Siding Spring's encounter with Mars.
NASA / JPL

Hubble and Spitzer are just two components of a 16-pronged attack that NASA scientists will be using to record the historic encounter.

The most anticipated of these observations will come from the three NASA orbiters (and its rovers Curiosity and Opportunity) with front-row seats. "Normally you would send a spacecraft to the comet," noted NASA planetary scientist Kelly Fast during a briefing last week. "In this case the comet is coming to the spacecraft."

A summary of the observations of Comet Siding Spring planned with the five NASA spacecraft currently at Mars. Click on the image for a larger version.
NASA / CIOC

Also on the scene are the European orbiter Mars Express and India's Mars Orbiter Mission (MOM). Although these two will not be protected by the planet, the Mars Express flight team plans to shut down nonessential systems and turn the craft so its big dish antenna can serve as a dust shield.

This plot shows how Comet Siding Spring (C/2013 A1) brightened in the year after its discovery but faded significantly in the past few months. It's now at least a full magnitude dimmer than predicted.
CIOC

Comet Siding Spring passes through its orbit's perihelion just 5 days after zipping past Mars, so activity should be very high. However, observers noted a fall-off in the comet's brightness earlier this month. There might be several explanations for this, but for now scientists are doing more watching than speculating.

One key observation will come from MRO's HiRISE camera, whose images should be able to resolve the comet's nucleus (though it'll appear just a few pixels across)."This one is really difficult," cautions Alfred McEwen (University of Arizona), who heads the HiRISE team, "but we'll have a good story to tell if it succeeds."

Meanwhile, since dynamicists expect the comet's extended gas-and-dust coma to envelop the planet briefly, MAVEN and MOM will both be watching for changes in the composition and temperature of the planet's upper atmosphere. Spotting a burst of meteors isn't out of the question.

More information about this unprecedented encounter is here. Be sure to check out this dramatic NASA animation (but ignore the over-the-top soundtrack).

Our special issue, "Mars: Mysteries & Marvels of the Red Planet," is loaded with spectacular photos and a must-read for anyone interested in this intriguing neighboring world.

The post Comet Siding Spring Skims Past Mars appeared first on Sky & Telescope.

Categories: Astronomy

G2 Survives Black Hole Pass

Sky and Telescope - Fri, 17/10/2014 - 05:39

The object has survived its swing around the Milky Way’s supermassive black hole, but the questions of what it is and where it comes from remain unanswered.

This spring, astronomers around the world watched a mysterious, gaseous object called G2 slingshot around the Milky Way’s supermassive black hole. They pointed instruments from radio dishes to X-ray satellites at our galaxy’s center, hoping for insight into the object itself and the environment around the black hole.

Of course, as with most scientific endeavors, the results have raised a bunch of questions.

Star and/or Cloud?

In 2011 astronomers spotted a gaseous object (red-yellow blob above center, with orbit shown in red) zooming toward the supermassive black hole in the Milky Way's core. The stars orbiting the black hole are also shown, along blue lines marking their orbits. The stars and the object, called G2, are shown in their actual positions in 2011.
ESO

Astronomers first spotted the bit of infrared-emitting fuzz that is G2 in 2011. It’s been a subject of debate since then, largely because of its crazy orbit. Although many stars and gas streamers crowd in near the black hole, objects generally have nondescript, elliptical orbits around that central beast. But G2 follows a “supersquinched ellipse,” making a beeline for the black hole, whipping around it, and shooting straight back out again, says galactic center researcher Daryl Haggard (Amherst College).

To do that, the object must have lost enough momentum that, instead of following a more circular orbit, it started to fall headlong toward the black hole. You can think of it like a coin rolling around a bowl: put enough speed on the coin, and it’ll follow an orbit around the rim; without that momentum, the coin will just roll straight to the bottom. So something must have robbed G2 of that energy. “And that’s just very difficult to understand,” Haggard says.

Much ink (both print and electronic) has been spilt trying to explain what stripped G2’s momentum. The answer is twisted up in the nature of G2: is it merely a gas cloud, or does G2 hide a star inside the cloud?

Two teams are spearheading the infrared observations that peer through the dust, enabling astronomers to see the stars and gas in the galactic downtown. One team, led out of the Max Planck Institute for Extraterrestrial Physics in Germany, favors the cloud idea; the other, out of the University of California, Los Angeles, favors the star idea. Even here at the office my colleague Monica and I have a running bet on which side is right. (The winner gets a plate of homemade cookies.)

Comparing Apples and Oranges

The central parts of our galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO's Very Large Telescope. By following the motions of the most central stars, astronomers can determine the mass of the supermassive black hole that they orbit.
ESO / Stefan Gillessen et al.

The hope was that G2 would reveal its nature during its close encounter this past March with the black hole, Sagittarius A*. However, the data are still inconclusive.

The most serious consequence of the continuing mystery is that I’m still waiting for my plate of cookies. My tummy has to wait because it’s hard to unite the two teams’ observations into a coherent picture. The teams depend on different types of observations. The MPI team has fabulous measurements from the SINFONI spectrograph at the European Southern Observatory’s Paranal site in Chile. The spectroscopic data for G2 from late summer 2013 through spring 2014 show an extended gas tail disrupted during the close pass.

On the other hand, the UCLA team has exquisite images from the Keck Observatory on Mauna Kea. The images for spring and summer 2014 show an unresolved compact object that didn’t brighten and stuck to its orbit during the pass, as you’d expect for a dust-enshrouded star.

The UCLA team suggests that the discrepancy comes from the fact that the two types of observations are looking at different features: the spectra catch gas that’s stretched out from the orbit, while the images catch the dusty shell heated by the star within. The MPI observations thus don’t rule out a star; they just show that gas is yanked out during the close pass.

If Sgr A* slowly brightens in the next few years, it’ll indicate that it did indeed tear gas off G2 and that this gas fell through the accretion flow toward the black hole. That could reveal G2’s nature and how much stuff it lost during the pass.

To Shock Or Not To Shock

The orbits of stars within the central 1 square arcsecond of the Milky Way, centered on the location of the central black hole (yellow star symbol). The fuzzy blobs are diffraction-limited star images in a frame taken by the 10-meter Keck telescope in 2004. While every star in this image has been seen to move, estimates of orbital parameters are only possible for those that have had significant curvature detected. The annual average positions for these seven stars are plotted as colored dots, which have increasing color saturation with time. Also plotted are the best fitting simultaneous orbital solutions. These orbits provide the best data yet on the mass of the central black hole. Click here for the movie.

Unfortunately for now, the conversation is largely limited to those working with infrared and ultraviolet data and theoretical simulations: those working in X-ray and radio have seen nothing. “We’ve all just been staring at the data, wishing it would appear,” says Haggard. “And it hasn’t.”

This absence is a surprise. Astronomers expected X-ray and radio emission to appear as G2 rammed its way through the hot gas around the black hole, creating a shock wave. But that didn’t happen.

This might not be the first time, either. Dozens of stars whiz around the galactic center, and one of them, S2, comes closer to Sgr A* than G2 did. That star should also have created a shock during its closest approach in 2002, but spotty data from NASA’s Chandra X-ray Observatory showed no sign of one. Astronomers hope that much better observations during S2’s next pass in 2018 will settle the question.

If S2 creates a shock, then G2 is weird. This scenario would strengthen the MPI team’s argument that G2 is a clump in a cloud streamer torn from a star, falling along a path that its (not-yet-found) parent star cleared out for it. That suggestion builds off simulations by James Guillochon (Harvard-Smithsonian Center for Astrophysics) and his colleagues that show G2 could be a cloud stripped off a star during its own close pass around the black hole.

But if S2 doesn’t create a shock, then there’s something funky about the accretion flow around the black hole — maybe the material in that flow is too hot or too diffuse (or both) to be shocked. It’s fair to say that, while G2 has captured the imagination, understanding it is only part of the much greater adventure of exploring the galactic center.

 

References:

O. Pfuhl et al. “The Galactic Center Cloud G2 and Its Gas Streamer.” Posted to arXiv.org July 16, 2014.

G. Witzel et al. “Detection of Galactic Center Source G2 at 3.8 Microns During Periapse Passage.” Posted to arXiv.org October 7, 2014.

R. A. Murray-Clay and A. Loeb. “Disruption of a Proto-Planetary Disk by the Black Hole at the Milky Way Centre.” Nature Communications, September 11, 2012.

J. Guillochon et al. “Possible Origin of the G2 Cloud from the Tidal Disruption of a Known Giant Star by Sgr A*.” Posted to arXiv.org January 13, 2014.

What's inside a black hole? Explore these questions and more in Sky & Telescope's Astronomy's 60 Greatest Mysteries.

The post G2 Survives Black Hole Pass appeared first on Sky & Telescope.

Categories: Astronomy

Nak tau mana kawasan mana atas Komet 67P si robot Philae akan mendarat ? Nahh ni...

Facebook - Thu, 16/10/2014 - 15:12
Nak tau mana kawasan mana atas Komet 67P si robot Philae akan mendarat ? Nahh ni dia...

https://www.flickr.com/photos/europeanspaceagency/15518481896/


Philae's primary landing site from 30 km
www.flickr.com
Close-up of the region containing Philae’s primary landing site J, which is located on the ‘head’ of Comet 67P/Churyumov–Gerasimenko. The mosaic comprises two images taken by Rosetta’s OSIRIS narrow-angle camera on 14 September 2014 from a distance of about 30 km. The image scale is 0.5 m/pixel. The…
Categories: Astronomy

Artikel FO: Terkini Komet Siding Spring http://falakonline.net/semesta/2014/10/...

Facebook - Thu, 16/10/2014 - 14:00
Artikel FO: Terkini Komet Siding Spring

http://falakonline.net/semesta/2014/10/terkini-komet-siding-spring/


Terkini Komet Siding Spring
falakonline.net
Agak lama tak menulis, gara-gara terpesong dengan pelbagai urusan lain. Ada yang bertanya khabar mengenai Komet Siding Spring yang dijangkakan akan berlanggar dengan planet Marikh pada 19 Oktober n...
Categories: Astronomy

Selain daripada galaksi Large Magellanic Cloud dan Small Magellanic Cloud, yang...

Facebook - Thu, 16/10/2014 - 10:04
Selain daripada galaksi Large Magellanic Cloud dan Small Magellanic Cloud, yang menjadi ikon kepada langit sebelah selatan, ada sebuah lagi objek yang menjadi daya tarikan.. iaitu Nebula Eta Carinae

Ia terletak di buruj Carina, sebelah kanan dari kedudukan buruj Crux (Pari), Di Malaysia, ia agak tinggi (sama level dengan buruj Crux), so agak senang nak ngendap dia...

Ia merupakan sebuah nebula gergasi yang besar, malah jauh lebih besar daripada Orion Nebula.

Ia terletak pada kedudukan 7500 Tahun Cahaya daripada bumi!


Foto Garis Masa
Eta Carinae upside down and rising Total Exposure 21.5 minutes 5DMkii (mod) 50mm f/5.6 ISO3200 Vixen Polarie PixInsight Coonabarabran, Australia. 30 Sep 2014 https://www.flickr.com/photos/shahgazer/15540524102
Categories: Astronomy

Zodiacal Light – Captivated by Comet Dust

Sky and Telescope - Wed, 15/10/2014 - 23:31

October's a perfect time to see the zodiacal light, a tapering tower of comet dust standing high in the eastern sky before dawn. Here's how to find it.

The fat-fingered glow of zodiacal light tilts up from the eastern horizon shortly before dawn.
Bob King

Wednesday morning, 5:30 a.m. I'm driving too fast down a country road in search of a clear sky to watch the total lunar eclipse. Totality is underway, but clouds in the west smother the Moon. I stop the car and get out to scan the sky for my next move ... and suddenly there it is. The zodiacal light.

Like a finger pointing the way, a tapered cone of light towers halfway up the eastern sky. Of course, I think. Head east. At least it's clear in that direction. Fifteen minutes later, a fragile, orange-red Moon emerges from the gloom.

For me, the zodiacal light was an omen that morning. For all of us, it's an opportunity to see how nature fashions cast-off comet and asteroid dust into an ethereal glow visible in a dark sky before dawn in the fall.

The zodiacal light (left) reaches up beyond Jupiter to cross over the Milky Way in this photo taken on October 1, 2014, under very dark, mountaintop skies on Tenerife. Details: 8mm f/3.5 fisheye, two 3-minute exposures at ISO 1600.
Damian Peach

The zodiacal light runs along the zodiac, a band of sky centered on the Sun’s apparent path through the heavens called the ecliptic. It's here you'll find the Sun, Moon, and all the planets as they scuttle through the 12 familiar zodiac constellations. During fall, as seen from the northern hemisphere, the ecliptic tilts up at a steep angle from the eastern horizon, bringing into view a softly-luminous pyramid or finger of light at dawn. To the uninitiated, it strongly resembles a glowing dome of light pollution from a nearby city, but its distinctive tapering shape and tilt set it apart.

This illustration shows a zodiacal light cone just before the start of dawn on October 21, 2014, when a very thin lunar crescent will rise at its base. The zodiacal light is aligned with the ecliptic, the Sun's apparent path across the sky during the year.
Source: Stellarium

Sunlight reflecting off comet and asteroid dust concentrated in the plane of the solar system creates the zodiacal light. Heat from the Sun vaporizes dust-laden comet ices, which expand outward to form the comet's coma and tail. Liberated from the grip of the icy nucleus, the dust is cast off into space. Dust from asteroid collisions also contributes a significant fraction to the pot.

Much of the dust settles into a vast, rarefied cloud in the plane of the solar system where it scatters sunlight, glowing like a cloud of foggy breath you exhale on a cold morning. Dust closer to the brilliant Sun scatters light back to our eyes with greater intensity; dust farther away less so. That’s why the zodiacal light is brighter at its base — which is closer to the rising Sun — than at its tip.

The combined glow of dust particles in the plane of the solar system — primarily from comets but from also from asteroid collisions —  reaching from the Sun's vicinity to beyond Mars is responsible for creating the zodiacal light. Planets are shown as colored disks.
Bob King

Like going to the bank to making a weekly deposit, every time a comet passes through the inner solar system, it contributes billions more dust particles to the zodiacal light. Many of them eventually spiral in toward the Sun and get zapped, so the cloud has to be continually replenished. Not a problem. Comets come and go all the time, and new ones arrive from the Oort Cloud nearly every year.

In the northern hemisphere, we see the zodiacal light best in fall before dawn in the eastern sky (left) and in spring in the west (right) at the end of evening twilight. At these times, the Sun's path is angled most steeply to the horizon, tilting the otherwise faint cone of light to best advantage. Bob King

The best time to look for this unearthly glow is on moonless mornings starting about 2 hours before sunrise. Because much of it is as bright as the summer Milky Way, you don't need absolutely pristine skies to see it. Find a location with a dark eastern sky and look for a large, tapered glow that reaches 45° or higher. Make slow scans from left to right as you face east to help you see the contrast between the light pyramid and darker sky.

Comets shed dust when heat from the Sun vaporizes their dirty-icy nuclei. Solar radiation blows the dust back to form a tail which then sheds the material into space, creating and replenishing the zodiacal light. Counterclockwise from upper left: C/2013 R1 Lovejoy, 2P/Encke, C/2012 X1, and ISON.
Gerald Rhemann, Damian Peach, Gianluca Masi, and Gerald Rhemann

With no bright Moon to bother us, October 21 through November 4, 2014, is an ideal time to go out for a look. A second moonless period begins on November 20th, though the ecliptic angle will be shallower. As you take in the sight, consider that you're gazing at the single largest visible structure in the solar system created by some of its tiniest members — dust motes!

Seeking Sirius? Chasing Camelopardalis? Let the Night Sky Star Wheel help you find them!

The post Zodiacal Light – Captivated by Comet Dust appeared first on Sky & Telescope.

Categories: Astronomy

Pandangan ke arah sempadan buruj Taurus dan Perseus. Dalam foto ini kelihatan 3...

Facebook - Wed, 15/10/2014 - 13:07
Pandangan ke arah sempadan buruj Taurus dan Perseus. Dalam foto ini kelihatan 3 buah objek langit (samawi) tetapi hanya 2 saja yang mudah kelihatan dengan mata.

Di tengah/atas, kelihatan gugusan bintang Seven Sisters.

Sementara itu, ke kanannya, kelihatan sebuah bintang terang kemerahan, yang dikelilingi oleh puluhan bintang2 lain. Itulah bintang Aldebaraan bersama dengan gugusan Hyades.

Sementara itu, di sudut kiri bawah, kelihatan sebuah tompokan panjang bewarna merah. Itulah California Nebula, diberi nama sempena bentuknya yang sama dengan negeri California. Yang ini hanya mudah kelihatan menerusi rakaman astrofoto. Dengan mata memang out, x leh nampak kepada ianya kelam sangat.

Gitulah citenya hari ini...


Foto Garis Masa
California Nebula, Pleiades, Hyades.. and some trees 16 minutes total exposure 5DMkii (mod) 50mm f/5.6 ISO3200 Vixen Polarie PixInsight Coonabarabran, Australia. 30 Sep 2014 https://flic.kr/p/po4tq7
Categories: Astronomy

(Geologically) Recent Volcanoes on the Moon?

Sky and Telescope - Wed, 15/10/2014 - 06:33

Images from NASA's Lunar Reconnaissance Orbiter show dozens of small, curious features that might be volcanic eruptions in the past 50 to 100 million years.

Countless astronomers, both amateur and professional, have spent untold hours scrutinizing the Moon through telescopes for hints of volcanic activity. Numerous claims of "transient lunar phenomena" (TLP) have been made over the past two centuries, many involving the curious complex of features in and near the crater Aristarchus. But while amateur cameras occasionally record small asteroidal strikes, a volcanic event has never been conclusively witnessed.

Red circles indicate either a single irregular mare patch (IMP) at least 100 meters across or a cluster of smaller IMPs on the Moon's nearside. Labels: Aristarchus (A), Gruithuisen E-M region (GEM), Hyginus (H), Ina (I), Mare Nubium (MN), Mare Tranquillitatis (MT), Marius Hills (MH), Maskelyne (M), and Sosigenes (S).
NASA / GSFC / Arizona State Univ.

And yet, according to an article published in October 12th's Nature Geoscience, scores of small volcanoes on the Moon have likely erupted within the past 100 million years and could be younger than 50 million years.

The suspect locations are what geologists term irregular mare patches, or IMPs. While Sarah Braden (Arizona State University) and her colleagues can't say for sure that the IMPs truly are recent eruptions — none have shown any changes over time, for example — the evidence of such is strong.

These distinctive rock deposits, up to 3 miles (5 km) long, can be either rough, blocky outcrops or smooth patches with uniform texture. Both types exhibit very few impact craters, even down the 1½-foot (0.5-m) resolution of NASA's Lunar Reconnaissance Orbiter Camera, and their spectral characteristics suggest relatively fresh surfaces that have not been darkened by aeons of  exposure to space radiation.

Is this feature, called Ina D, a recent volcanic eruption on the Moon? This oblique view from the Lunar Reconnaissance Orbiter shows patches of smooth and rough terrain in a shallow depression about 200 feet (50 m) deep. The entire scene is about 2 km wide; illumination is from the bottom.
NASA / GSFC / Arizona State Univ.

The best known IMP, named Ina (or Ina D), was spotted in images taken by the crew of Apollo 15 in 1971. Even back then, lunar geologists had a hunch that Ina was a collapsed vent topping a low, broad shield volcano. But Ina's age has long been uncertain.

Now, thanks to LRO's keen resolution, that site and many others appear to be quite fresh. Curiously, all the IMPs are on the Moon's nearside hemisphere, though statistically a few should have been spotted on the farside.

So, rather than a complete shutdown of lunar volcanism at least a billion years ago, as had been widely assumed, the process was apparently much more drawn out. Pockets of molten rock must have remained in the lunar mantle until very recently — and might still be there now. These findings have implications for how warm the lunar interior still is (and the true extent of its partially molten core).

For some expanded thinking on what this all means for the Moon's current state and long-term evolution, see this excellent post by Mark Robinson, who heads the LRO Camera team.

Want to compare the Moon's nearside and farside for yourself? Check out Sky & Telescope's terrific new lunar globes. Choose either the natural-hued Moon you see by eye or the color-coded topographic version.

The post (Geologically) Recent Volcanoes on the Moon? appeared first on Sky & Telescope.

Categories: Astronomy

Melayan time lapse Gerhana Bulan Penuh haritu... ni dari negara New Zealand tau....

Facebook - Tue, 14/10/2014 - 17:44
Melayan time lapse Gerhana Bulan Penuh haritu... ni dari negara New Zealand tau... bukan Felda Kampung New Zealand! ;-)

http://www.youtube.com/watch?v=0ktzK2_nfAY&feature=youtu.be


Lunar Eclipse 8th October 2014

Taken at 5 minute intervals with a EOS350d DSLR and WO FLT132 refractor
Categories: Astronomy

2 buah galaksi 'satelit' Bima Sakti, yang dikenali sebagai Small Magellanic Clou...

Facebook - Tue, 14/10/2014 - 12:34
2 buah galaksi 'satelit' Bima Sakti, yang dikenali sebagai Small Magellanic Cloud (kiri) dan Large Magellanic Cloud, merupakan 2 buah objek samawi yang begitu mudah dilihat dengan mata kasar, dari langit hemisfera selatan.

Kita di Malaysia, agak susah untuk melihatnya kerana kedudukannya agak rendah di ufuk selatan, dan tidak akan berada tinggi di langit.


Foto Garis Masa
The Large and Small Magellanic Clouds, the southern gems and a must-see pair! 30 minutes total exposure 5DMkii (mod) 50mm f/5.6 Vixen Polarie PixInsight Coonabarabran, Australia. 30 Sep 2014 https://www.flickr.com/photos/shahgazer/15340390770/
Categories: Astronomy

No Big Black Hole for Two ULXs

Sky and Telescope - Tue, 14/10/2014 - 01:18

Two studies suggest that ultraluminous X-ray sources are not all created by beefy black holes.

The surprisingly bright objects known as ultraluminous X-ray sources (ULXs) are not all alike, new research shows. ULXs spew out X-rays at luminosities millions of times the Sun’s total luminosity, and roughly a trillion times the Sun’s luminosity in X-rays. When they were first discovered three decades ago, astronomers thought they might be the glow from gas-gobbling intermediate-mass black holes. These theoretical objects have masses of hundreds to thousands of Suns and would fill the no-man’s land between stellar-mass black holes and supermassive black holes. Subsequent research has failed to conclusively settle the question.

High-energy X-rays streaming from a mighty pulsar (magenta) blaze in this composite image of the galaxy M82. The image combines multiwavelength data from three telescopes: visible-light data from NOAO's 2.1-meter telescope at Kitt Peak, low-energy X-ray data from NASA's Chandra X-ray Observatory (blue), and higher-energy X-ray data from NASA's NuSTAR (pink). The pulsar is an ultraluminous X-ray source (ULX), which astronomers had thought were all created by massive black holes. This source, called M82 X-2, is the brightest X-ray pulsar found to date.
NASA / JPL-Caltech / SAO / NOAO

But recent results show that there’s more than one way to make a ULX. A pair of papers published on October 9th in Nature reveal the inner workings of two ULXs, and demonstrate that neither is an intermediate-mass black hole.

The standard explanation for ULXs is that they result from black holes accreting matter from a companion star. As the matter is pulled into an accretion disk before falling into the black hole, it is heated to extreme temperatures and radiates X-rays.

But a theoretical constraint on how quickly a black hole can gobble up matter — known as the Eddington limit — puts a cap on how bright such objects can be. If the black hole tries to swallow too much matter at once, the outward pressure of radiation from that material pushes back on the matter falling in, cutting off the black hole’s meal. The radiation-gravity balance means that a black hole’s brightness has a limit.

The more massive the black hole, the brighter it can be. But ULXs are uncomfortably bright: to explain them, a stellar-mass black hole would need to reach or surpass its Eddington limit. That suggests these sources are intermediate-mass black holes. Among all ULXs, the sources M82 X-1 and ESO 243-49 HLX-1 are the two best candidates; evidence suggesting that M82 X-1 is a 400 solar-mass black hole recently appeared in the September 4th issue of Nature.

Another favored explanation for ULXs is that they are stellar-mass black holes that exceed the Eddington limit — and are therefore more luminous than expected — due to a “force-feeding” of the black hole that can occur under certain conditions.

Now, Christian Motch (University of Strasbourg, France) and a team of astronomers found evidence of a ULX doing just that. The ULX is located in the spiral galaxy NGC 7793, 12 million light-years from Earth. By observing variations in the light from the system, the team measured the orbital period of the black hole and its companion to 64 days and constrained the mass of the black hole to be less than 15 solar masses. This means that the black hole at the center of this ULX gobbles up matter at twice its Eddington limit, confirming the force-feeding picture.

But nature is prone to throw curveballs. Matteo Bachetti (University of Toulouse, France) and colleagues found that another ULX was not a black hole at all, but a pulsar — an explanation astronomers hadn’t anticipated. The team used NASA’s NuSTAR telescope to examine the signal from another ULX in the galaxy M82, also 12 million light-years away, and were surprised to see pulsations: the dead giveaway of a pulsar. The ULX is more than 10 times brighter than any accreting pulsar seen thus far.

Scientists had not expected pulsars to be an explanation for ULXs, because they would have to exceed their Eddington limits to an extreme degree. In this case, the Eddington limit is surpassed by a factor of 100 — an unprecedented amount, difficult to reconcile with theory.

“It’s going to send the theorists back to the drawing board to figure out how that object can actually be accreting at this high rate,” says Philip Kaaret (University of Iowa), who was not involved with the research.

It’s not yet clear how many ULXs can be explained by each of the three possibilities: pulsars, stellar-mass black holes, and intermediate-mass black holes. But if pulsars were a common culprit, they would likely have been found out already, says Richard Mushotzky (University of Maryland). “We’re now forced to realize that what previously had been one class of objects is at least three classes of objects, and maybe more,” he says. “Nature is a lot more rich and complex than even our imagination can grasp.”

Scientists now may want to take a closer look at some ULXs they’ve assumed were run-of-the-mill. One thing’s for sure: Occam’s razor does not apply.

 

References:

C. Motch et al. "A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source." Nature. October 9, 2014.

M. Bachetti et al. "An ultraluminous X-ray source powered by an accreting neutron star." Nature. October 9, 2014.

Download our eBook on black holes when you register for S&T's website — both registration and the eBook are free! (If you're already registered, then just sign in and download away!)

The post No Big Black Hole for Two ULXs appeared first on Sky & Telescope.

Categories: Astronomy

Work Begins on Thirty Meter Telescope

Sky and Telescope - Fri, 10/10/2014 - 20:23

Officials proceed with groundbreaking ceremonies for the world's largest optical telescope amid protests from native Hawaiians who oppose it.

Under beautifully clear skies — just the kind that have made the summit of Hawaii's Mauna Kea a mecca for astronomical observatories — officials gathered on October 7th for the dedication and groundbreaking of the Thirty Meter Telescope.

When completed in 2022, the mammoth Thirty Meter Telescope will have eight times the light-gathering area of any other optical telescope.

The ceremony demonstrated the combustible mix of science, local traditions, and politics that have dogged the summit's development for decades and the TMT project in particular. The ceremony was interrupted for several hours as local opponents staged a peaceful protest, using their cars to block the road leading to the summit. Some held signs using TMT to spell out "Too Many Telescopes."

Mauna Kea, often translated as "White Mountain" because it's sometimes capped with snow, rises 13,796 feet (4,205 m) from the Pacific Ocean and is sacred to native Hawaiians. The dormant volcano is known locally as wao akua ("realm of the gods"), and its slopes are dotted with shrines, altars, and hidden burial grounds.

According to the master plan drawn up in 1983 (extended in 2000) between state environmental officials and the University of Hawaii, which manages the summit, no more than the 13 domes can be built on the summit. This limitation ultimately led to cancellation of plans to add four small "outrigger" telescopes to Keck Observatory's existing giant twin domes.

TMT: A Monster Telescope

Despite the protests, construction for the TMT has been approved and will move forward. When completed, perhaps as early as 2022, the telescope will leapfrog to the top ranking of the world's largest optical telescopes.

Each of the 492 mirror segments that comprise the Thirty Meter Telescope's f/1 primary mirror will be constantly adjusted for optimum alignment. An 11½-by-8-foot pickoff mirror protrudes through the central opening and directs light sideways to one of several planned instruments.

Exploiting technology pioneered for the twin Keck telescopes, the TMT will combine 492 individual hexagonal reflectors, each 1.4 meters across, honeycombed together to yield a primary mirror with an effective diameter of 30 m (98 feet). That giant primary will provide 144 times more collecting area and 10 times better spatial resolution than the Hubble Space Telescope.

"This is an exciting moment as we begin construction of TMT," noted Edward Stone in a prepared statement. A veteran Caltech space physicist, Stone serves as executive director of TMT International Observatory (though he's better known as project scientist for NASA's Voyager mission).

TMT is the first of what could be multiple mega-telescopes designed to vastly improve the ability of ground-based telescopes to peer into the faint, deep cosmos. The race is on to build TMT and two competing projects: the 27-meter Giant Magellan Telescope (GMT) and the European Extremely Large Telescope (EELT).

Such "megascopes" should open the door to major discoveries in all facets of astronomy. Finding the composition of distant exoplanets, mapping the large-scale structure of the universe, and probing the earliest galaxies are all on the long "to-do" list that astronomers are drawing up for the TMT. Plans call for three "early light" instruments: a wide-field, multiobject spectrograph (WFOS); a near-infrared imaging spectrometer (IRIS); and a multi-slit, near-infrared imaging spectrometer (IRMS). The telescope will utilize an adaptive-optics system to cancel out atmospheric turbulence and achieve diffraction-limited performance.

It's an enormous project, both physically (the summit site covers about 5 acres) and financially. With an estimated price tag of $1.4 billion, TMT is too costly for any one institution to undertake. Instead, it's a joint international venture involving the California Institute of Technology, Chinese Academy of Sciences, Japan's National Institutes of Natural Sciences and National Astronomical Observatory, and the University of California. India and Canada plan to join the partnership soon.

Read contributing editor Robert Zimmerman's article about the construction mega-telescopes in the March 2014 issue of Sky & Telescope.

The post Work Begins on Thirty Meter Telescope appeared first on Sky & Telescope.

Categories: Astronomy

This Week’s Sky at a Glance, October 10 – 18

Sky and Telescope - Fri, 10/10/2014 - 17:05
Some daily sky sights among the ever-changing stars and planets

Friday, October 10

The waning gibbous Moon is up in the east by 9 or 10 p.m. Look left of it (by about a fist-width at arm's length) for the Pleiades. Much farther left, in the northeast, shines Capella in Auriga.

High above the Moon and Capella, forming a big triangle with them, is the naked-eye eclipsing variable star Algol. It should be at its minimum light, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 12:36 a.m. tonight EDT; 9:36 p.m. PDT. Algol takes several additional hours to fade and to recover. Info and comparison-star chart.

The waning Moon and Orion tip to the southwest as dawn brightens. (The Moon in these scenes is always shown three times its actual apparent size.)

Saturday, October 11

The Moon late this evening shines near Aldebaran amid the Hyades. Take a look with binoculars. This will be a challenging scene to photograph (use a long lens), what with the Moon's brilliance and the Hyades stars' faintness. By dawn they've moved over to high in the southwest.

Sunday, October 12

Orion preview: With fall well underway, the "winter" constellation Orion rises in the east by 11 or midnight, depending on how far east or west (respectively) you live in your time zone. It's well to the lower right of the waning Moon. Orion's Belt will be vertical, as it always is when Orion is rising for mid-northern skywatchers. Orion reaches its highest stand in the south well before the first light of dawn, with the Moon now above it (on the morning of the 13th).

Monday, October 13

As twilight fades, look for Arcturus, the Spring Star, twinkling in the west to west-northwest. It's still pretty easy to see. But how much later into the fall, as it sinks away, will you be able to keep it in view?

Tuesday, October 14

Now that it's mid-October, Deneb has replaced Vega as the zenith star after nightfall (for skywatchers at mid-northern latitudes) — and, accordingly, Capricornus has replaced Sagittarius as the most notable constellation low in the south.

Wednesday, October 15

Last-quarter Moon (exactly so at 3:12 p.m. Eastern Daylight Time). The Moon rises around midnight tonight, below Gemini. By early dawn on Thursday the 16th it's very high in the south — with Pollux and Castor above it, Procyon to its lower right, and bright Jupiter shining farther to its lower left.

Watch the thinning crescent Moon pass Jupiter and Regulus in early dawn.

Thursday, October 16

Dawn and sunrise come quite late now as the season advances. On Friday morning the 17th, before the sky gets too bright, you'll find Jupiter to the left of the waning Moon, and Procyon farther to the Moon's right.

Friday, October 17

Before dawn Saturday morning, Jupiter shines above the waning Moon. Although they look rather close together, Jupiter is 2,100 times farther in the background — at a distance of 47 light-minutes, compared to the Moon's 1.3 light-seconds.

Saturday, October 18

This is the time of year when, after nightfall, W-shaped Cassiopeia stands on end halfway up the northeastern sky — and when, off to its left, the dim Little Dipper extends leftward from Polaris in the north.

On Sunday the 19th, the faint Comet Siding Spring (C/2013 A1) makes its much-awaited close pass by Mars, as told in the September Sky & Telescope, page 53, with chart. This will be an extremely challenging observation, with Mars low in the southwest right at the end of twilight and the comet only 10th or 11th magnitude, fainter than originally predicted. But you can follow a webcast of the encounter courtesy of the Virtual Telescope project; watch in real time starting at 16:45 UT (12:45 p.m. EDT) October 19th, or the recording later. Also: NASA Prepares Its Science Fleet for Oct 19 Mars-Comet Encounter.

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).

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 and Venus are hidden in the glare of the Sun.

Mars (magnitude +0.8) remains low in the southwest during dusk. Look for twinklier orange Antares (magnitude +1.0) moving ever farther down to Mars's lower right.

Jupiter (magnitude –1.9, at the Cancer-Leo border) rises in the east-northeast around 2 a.m. It shines brightly high in the east before and during dawn. Jupiter forms a big triangle with Pollux above it (by about two fists at arm's length) and Procyon to their right. Below Jupiter and a bit left is Regulus.

Saturn (magnitude +0.6, in Libra) is sinking very low after sunset. As twilight fades, look for it well to the right of Antares, which is lower right of Mars. Bring binoculars.

Uranus (magnitude 5.7, in Pisces) and Neptune (magnitude 7.8, in Aquarius) are high in the southeast and south, respectively, by 9 or 10 p.m. See our finder charts for Uranus and Neptune online or in the September Sky & Telescope, page 50.

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 Daylight Time (EDT) is Universal Time (UT, UTC, or GMT) minus 4 hours.

“This adventure is made possible by generations of searchers strictly adhering to a simple set of rules. Test ideas by experiments and observations. Build on those ideas that pass the test. Reject the ones that fail. Follow the evidence wherever it leads, and question everything. Accept these terms, and the cosmos is yours.”

— Neil deGrasse Tyson, 2014.

 

The post This Week’s Sky at a Glance, October 10 – 18 appeared first on Sky & Telescope.

Categories: Astronomy

Ada di Wangsa Maju? Jom kita jumpa di Masjid Usamah bin Zaid, esok 11 Oktober 20...

Facebook - Fri, 10/10/2014 - 16:01
Ada di Wangsa Maju? Jom kita jumpa di Masjid Usamah bin Zaid, esok 11 Oktober 2014, Sabtu malam Ahad, sekitar jam 10 malam, untuk Ceramah Umum Astronomi dan jika langit ok, meneropong langit.

Nota: Baru terima jemputan tadi. So dalam banner tu x tertulis. :-)


Muat Naik Mudah Alih
Karnival datang lagi. Jom meriahkan bersama:-) — bersama Azhar Abd Hamid dan 49 yang lain.
Categories: Astronomy

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