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).


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



Mediterranean Sky

Sky and Telescope - Wed, 04/11/2015 - 06:43

The post Mediterranean Sky appeared first on Sky & Telescope.

Categories: Astronomy

Aktywne Słońce (Solar Activity)

Sky and Telescope - Wed, 04/11/2015 - 01:29
Categories: Astronomy

Small Galaxies Helped Light Up Universe

Sky and Telescope - Tue, 03/11/2015 - 23:42

Hubble observations confirm that much of the light that broke up the early universe’s hydrogen came from the smallest galaxies.

These images from the Hubble Space Telescope show three galaxy clusters (top to bottom): MACS J0717.5+3745, Abell 2744, and MACS J0416.1–2403. Astronomers are studying these and three other clusters as part of the Hubble Frontier Fields program, which uses the phenomenon of gravitational lensing to study distant, early galaxies that would otherwise be too faint to be detected. Observations of more than 250 small galaxies lensed by these clusters reveal that such galaxies contributed substantially to the ultraviolet radiation that reionized the early universe’s neutral hydrogen.
NASA / ESA / HST Frontier Fields team (STScI)

In the universe’s early years, after the primordial plasma cooled down and became transparent, the cosmos was a sea of neutral hydrogen. The sea was a clumpy one. These clumps ultimately became the first galaxies, their stars beginning to shine only a few hundred million years after the Big Bang.

The first stars poured ultraviolet radiation into the universe. But ultraviolet rays are like kryptonite to neutral hydrogen: the photons ionize the atoms. In fact, within the first billion years of cosmic birth, there was so much UV around that most of the universe’s hydrogen was ionized, turning the space between galaxies into a cooled-down version of the primordial plasma.

It’s surprisingly difficult to say just when this epoch of reionization occurred. The timing is important because it tells us when stuff happened in the early universe. Pin down when UV flooded the cosmos, and you can say how fast the things producing that UV — galaxies, madly gobbling black holes — arose.

Astronomers think that almost all of the ultraviolet radiation responsible for reionization came from star-forming galaxies (not, say, their black holes). Observers also have evidence that later on — about 2 to 3 billion years later — the smallest galaxies were pumping out 70% of the universe’s stars. So they’ve started wondering just how much of a role galaxies a fraction of the Milky Way’s size played in reionization. Computer simulations last year suggested that they might contribute 30% of the UV to reionize the universe.

New observations with the Hubble Space Telescope confirm that small galaxies played a big role. Hakim Atek (Ecole Polytechnique Fédérale de Lausanne, Switzerland, and Yale) and colleagues went hunting for early, faint galaxies using the magnifying power of three massive galaxy clusters’ gravity, an effect called gravitational lensing. They detected 252 galaxies from about 650 to 950 million years after the Big Bang. That’s a notable uptick in astronomers’ early galaxy census: less than two years ago, we’d observed only about 1,400 galaxies from this era.

These new galaxies are at least two magnitudes fainter than those previously used to study early galaxies’ energy output. Atek’s team confirmed that indeed, these small galaxies put out lots of UV, enough to make up for what was lacking from big galaxies and totally reionize the universe by about 750 million years after the Big Bang. Depending on where the astronomers draw the line for what qualifies as a small, faint galaxy, these stellar cities contributed between about 20% (just the faintest, newly found) and 60% (including the previous, brighter ones) of the ultraviolet radiation. At first glance that's in keeping with the 30% from last year's simulations, but Atek cautions comparing them isn't straightforward because of the different estimates involved.

You can read more about the study in the press release, or the team’s paper, which will appear in Astrophysical Journal.


Reference: H. Atek et al. “Are Ultra-faint Galaxies at z=6-8 Responsible for Cosmic Reionization ? Combined Constraints from the Hubble Frontier Fields Clusters and Parallels.” To appear in Astrophysical Journal.


Enjoy more science and observing news with a subscription to Sky & Telescope magazine.

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Categories: Astronomy

Mystery Object to Reenter Earth’s Atmosphere

Sky and Telescope - Tue, 03/11/2015 - 23:30

WT1190F will burn up over the Indian Ocean on November 13th, giving researchers an unprecedented opportunity to follow its path — and figure out where it came from.

An animation of WT1190F moving against the starry background on October 9th.
B. Bolin, R. Jedicke and M. Micheli

An unknown object is headed for a fiery demise over the Indian Ocean on November 13th – and observations so far show it might be a relic of the early Space Age.

The object in question is WT1190F, first observed by the Catalina Sky Survey in 2013. A couple years of observations have characterized its curious orbit: its highly eccentric path around Earth takes the object from its nearest point (perigee) of 21,221 kilometers (13,186 miles) out to an apogee of 655,370 kilometers, 1.7 times the distance between Earth and the Moon.

What Is WT1190F?

A diagram depicting the looping orbit of WT1190F. The blue circle is the Moon’s orbit.
Bill Gray / Project Pluto

Studies from the International Astronomical Union’s Minor Planet Center and the European Space Agency’s NEO Coordination Centre European Space Research Institute (ESRIN) suggest that WT1190F is probably a piece of discarded space junk from a Moon mission. Not only because of its orbit, but also because WT1190 interacts with solar radiation pressure in a way that suggests it has low density and might even be hollow — perhaps a rocket booster, solar panel, or SLA Panels (Spacecraft Lunar module Adapter panels used during the Apollo missions).

Calculations project WT1190F’s reentry above the Indian Ocean, just south of Sri Lanka, on November 13th at 6:19 UT (11:49 a.m. local time).

This event provides astronomers the chance to model a reentry from a highly eccentric orbit, so they can test similar scenarios involving incoming asteroids.

“The object is quite small — at most a couple of meters in diameter — and a significant fraction, if not all of it, can be expected to completely burn up in the atmosphere,” says Tim Flohrer in a recent ESA press release.

To this end, researchers plan to conduct airborne observations of WT1190F’s atmospheric reentry from a specially equipped Gulfstream 450 business jet, an effort organized by the International Astronomical Center (IAC) and the United Arab Emirates Space Agency in cooperation with the SETI Institute, the Clay Center Observatory, and the HEFDiG (High Enthalpy Flow Diagnostics Group) at the University of Stuttgart, Germany

ESA researchers led similar airborne operations to observe the reentry of Hayabusa, an asteroid sample return mission in 2010, as well as the reentry of ATV 1, an ESA supply spacecraft for the ISS, in 2008. See the video of Hayabusa's reentry:

To date, researchers are unsure just what lunar mission WT1190F belongs to. It will probably remain a mystery unless astronomers can link it to earlier observations.

“We’ve managed to identify the object with one found in 2013,” says Bill Gray (Project Pluto), who has been working with the PanSTARRS team to identify WT1190F and characterize its orbit. “That got us a good enough orbit that Marco Micheli was able to find images taken in December 2012 from PanSTARRS in Hawaii. So about all we can say at this point is, it was launched sometime before December 2012.”

But the more observations of WT1190F, the better. WT1190F won’t pose a good observational target for backyard observers — it’s currently only at magnitude 21 near apogee, though it’ll approach magnitude 15 pre-reentry, in range of large backyard scopes. Dedicated observers can generate topocentric ephemerides using the Minor Planet Center’s Distant Artificial Satellite Observations (DASO) page.

Space Junk and Low-Flying Space Rocks

Bill Yeung spotted an object, J002E3, in 2002, initially thought to be a near-Earth asteroid. Further observations showed that it's more likely the expended Saturn IVB stage of the Apollo 12 launch rocket, identical to that of Apollo 17 shown here.

The Department of Defense's Space Surveillance Network (SSN) uses radar and optical sensors to track more than 21,000 satellites and space debris down to sizes of about 5 centimeters (2 inches) in low-Earth orbit. In farther-out geosynchronous orbits, SSN can track objects down to sizes of about 1 meter. But researchers can only recover objects in wider-ranging orbits using imaging. Small, faint objects on wider orbits are extraordinarily difficult to find, and their orbits, complicated by the gravitational effects of the Moon, are difficult to characterize.

Other near-Earth asteroid discoveries have turned out to be space junk as well: J002E3 was a Saturn V third-stage booster from the Apollo 12 mission, and 2010 QW<sub>1</sub> turned out to be part of the Chinese Chang’e 2 lunar mission. The reentry of WT1190F, however, marks the first time astronomers have observed such an object returning to Earth.

Good luck to the team watching for WT1190F’s reentry on November 13th!

Further resources:

Read Bill Gray’s FAQ page at Project Pluto for an in-depth discussion on WT1190F.

Aerospace.org provides a current list of upcoming satellite and space junk reentries worldwide.

The post Mystery Object to Reenter Earth’s Atmosphere appeared first on Sky & Telescope.

Categories: Astronomy

Be Alert for Taurid Fireballs This Week

Sky and Telescope - Tue, 03/11/2015 - 22:27

If you see a really bright autumn fireball, it might be a Taurid meteor — a fragment of Comet 2P/Encke.

The Taurid meteors of October and November are unlike any other shower. They continue for many weeks, with two parallel components: the Southern Taurids, which run roughly through October and early November; and the Northern Taurids from late October through mid-November.

Skywatchers have determined that two Taurid meteor streams exist. Their respective radiants migrate over a large stretch of sky during October and November.
S&T diagram; source: IMO

The whole complex originates from periodic Comet 2P/Encke. Like the comet, the stream follows an unusually short-period orbit (about 3.3 years) near the plane of the ecliptic. Taurids catch up to Earth roughly from behind, so they are unusually slow — and the shower is as strong in the evening as in the morning hours.

Ordinarily the Taurids are a modest shower, offering roughly 20 meteors per hours under ideal dark-sky conditions. But this year the shower promises something more: a chance of occasional really brilliant fireballs, the kind that make the public call the police.

Comet Encke's debris is unusually rich in large particles. Meteor-stream modeler David Asher finds that Earth should pass through a relatively rich band of them this year. The likeliest dates run from shortly before Halloween to about November 10th.

Prospects are good for lesser meteors too. "Four of the last five northern-autumn Taurid swarm returns have each produced unusual, if variable, activity," according to the International Meteor Organization, "so there seems a good prospect that something may again happen this time."

Between October 10th and November 25th, the shower's radiant moves all the way from north of the head of Cetus to north of Aldebaran. Keep looking up, and if you see a slow meteor during October or November, check whether its path leads back toward that direction.

This Taurid fireball, captured October 28, 2005, is headed away from its radiant, or apparent source, in the constellation Taurus (at upper right).
NASA / Hiroyuki Iida

The strongest recent Taurid return came in 2005, when many fireballs made the news around the world. The name "Halloween fireballs" for Encke's spawn seems to date from that year. On November 7, 2005, two NASA researchers apparently recorded a Taurid hitting the night side of the waxing Moon. The tiny, 7th-magnitude flash on a video recording, the NASA team calculated, would have been caused by a 12-cm (5-inch) impactor if it arrived at the Taurids' speed of 27 km per second. It probably made a crater 3 meters (10 feet) wide and 0.4 meter deep.

So will we see lots of Taurid fireballs this coming week? The editors of Sky & Telescope make this prediction: "Meteor showers have a way of fooling everyone. So have realistic expectations, enjoy the celestial show, and be prepared for a surprise."

You'll know when to look for the Taurids meteors — or any celestial event — if you have Sky & Telescope's 2016 Observing Calendar handy.

The post Be Alert for Taurid Fireballs This Week appeared first on Sky & Telescope.

Categories: Astronomy

SCT Parallizer by Starlight Instruments

Sky and Telescope - Mon, 02/11/2015 - 21:00

Starlight Instruments
2380 E. Cardinal Dr., Columbia City, IN 46725

Starlight Instruments, in partnership with Howie Glatter, announces the SCT Parallizer ($60). This accessory adapter is designed to attach to any telescope that uses an SCT-threaded interface and hold 2-inch accessories in nearly perfect alignment using Howie Glatter’s patented Parallizer design. A non-marring clamp screw holds your 2-inch eyepiece, diagonal, or camera securely, and guarantees repeatable alignment to within 15 arcseconds with no possibility of wiggle or play.

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.

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Categories: Astronomy

Occultation Moon and Aldebaran

Sky and Telescope - Mon, 02/11/2015 - 05:05

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Categories: Astronomy

The Orion Nebula

Sky and Telescope - Sun, 01/11/2015 - 03:09

The post The Orion Nebula appeared first on Sky & Telescope.

Categories: Astronomy


Sky and Telescope - Sun, 01/11/2015 - 02:18

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Categories: Astronomy

2015 TB145 — Rogue Asteroid or Dead Comet?

Sky and Telescope - Sat, 31/10/2015 - 23:31

Astronomers can't decide whether the sizable object known as 2015 TB145, which is cruising past Earth today, is a renegade from the asteroid belt or a short-period comet with nothing left to give.

Ever since its discovery three weeks ago with the Pan-STARRS 1 survey telescope, the object now designated 2015 TB145 has been something of a paradox to astronomers. Telescopically it remained just a starlike point and thus probably an asteroid that got shoved onto an orbit that carries it in Earth's general vicinity. But that 3.1-year-long orbit is extremely long and narrow, with an eccentricity of 0.86 (0.00 is a perfect circle). Dynamicists see that as more comet-like.

A sequence of six range-Doppler radar maps, acquired with the 300-meter Arecibo Radio Telescope in Puerto Rico, reveals that the sppoky-looking near-Earth object 2015 TB145 is roughly 600 meters across — nearly twice as large as expected based on telescopic imaging. The smallest details are about 7½ meters (25 feet) across.
SRI Intl. / Ana G. Méndez Univ. System / USRA

Now, thanks to new observations, 2015 TB145 is looking more and more like a dead comet. Yesterday planetary specialists at the Arecibo Observatory in Puerto Rico probed the object with powerful radar pulses, and the resulting echos show that it's more or less round, rotates every 5 hours, and has a diameter of about 600 meters (2,000 feet). That's considerably larger than the initial estimates (300 to 400 m), and it means that 2015 TB145 is relatively big as near-Earth objects go.

The larger-than-expected size makes sense because this body turns out to be nearly black. By combining its visible-light brightness with scans made with NASA's Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai'i, researchers now estimate that the surface reflects only about 6% of the sunlight that strikes it. Most comets have a reflectivity in the range of 3% to 5%, but asteroids are usually considerably higher, around 15% to 20%.

Arecibo's radar probings show that 2015 TB145 has a kind of spooky appearance, reminiscent of a human skull. Two low-reflectivity "eye sockets" might turn out to be craters. (Technically, these aren't images in the usual sense; the radar echoes are instead two-dimensional maps that plot the pulses' round-trip light time versus the Doppler shift caused by rotation. Bright and dark areas correspond to radar reflectivity, not necessarily surface brightness.)

Other radar studies are planned throughout the weekend using the big Arecibo dish along with those at NASA's Goldstone facility in the Mojave Desert, the Green Bank Telescope in West Virginia, and Haystack Observatory in Massachusetts.

A Halloween Vigil for 2015 TB145

Meanwhile, astronomers around the world have been tracking this object as it zips past Earth at a relatively fast 35 km (22 miles) per second, a consequence of its elongated orbit. Dynamicists at the Jet Propulsion Laboratory calculate that when 2015 TB145 comes closest, at 17:01 Universal Time (1:01 p.m. Eastern Daylight Time), it will be 480,400 km (298,500 miles) away, about 30% farther than the Moon.

Here's how 2015 TB145 looked at 17:46 Universal Time on October 30th. Background stars trailed during the 2-minute exposure, recorded with a remotely operated 17-inch PlaneWave telescope and SBIG STL-6303E CCD camera. The field of view is about 8 arcminutes square.
Gianluca Masi / Virtual Telescope Project

Although making a rather distant pass, the object will brighten to magnitude 10.1. When closest to us, it is in Ursa Major and passes just ½° from 2nd-magnitude Phad in the Big Dipper's bowl. But at that time it's daylight all across North America. So for most North Americans the best opportunity to catch a glimpse of this interloper came early this morning, when it was near the Orion-Taurus border.

Yes, I dutifully got up at 5 a.m. to track it down by eye. It was a struggle: a fat gibbous Moon, less than 10° away, flooded the sky with scattered light. But thanks to my Celestron 9¼-inch telescope and a careful alignment, I was able to navigate directly to the object's location with relative ease. Faint but obvious, it moved slowly among the background stars.

Those of you in far-northern locations or in Europe or Asia can use the chart below as a guide for where to find 2015 TB145 for yourself. Just remember that Sky & Telescope's chart shows the apparent path as seen from Earth's center, and the object's proximity to Earth will create a positional shift in the sky due to parallax of ½° or more. Moreover, the position will change by more than a lunar diameter every 3 minutes when closest to Earth. So if you're trying to observe 2015 TB145, you'll need to get celestial coordinates specific to your location.

For more information, check out this JPL press release and this Virtual Telescope webcast moderated earlier today by Gianluca Masi.

This chart shows the path of 2015 TB145 as it sweeps past Earth at 35 km per second. During this 20-hour-long period the object's magnitude varies from 10.1 to 12.2, and its proximity to Earth will create a parallax shift of ½° or more. So you won't be able to point your telescope based on this track; instead, you will need to consult another source to generate positions specific to your location (see text). Click here for a full-size version of this chart or click here for a black-on-white version. Both are sized for tabloid (11-by-17-inch) paper.
S&T: Gregg Dinderman

The post 2015 TB145 — Rogue Asteroid or Dead Comet? appeared first on Sky & Telescope.

Categories: Astronomy

Asteroid 2015 TB145 Passes M44

Sky and Telescope - Sat, 31/10/2015 - 21:15

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Categories: Astronomy

LBN 603

Sky and Telescope - Sat, 31/10/2015 - 17:40

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Categories: Astronomy

The Star Barn

Sky and Telescope - Sat, 31/10/2015 - 05:14

The Star Barn


P.O. Box 161
Cave Creek, Arizona 85327-0161


Ronald Walker








Private planetarium dedicated to education and introducing individuals, families, school groups, scout groups to the wonders of the night sky.

Visit us at "The Star Barn Planetarium" on Facebook.

The post The Star Barn appeared first on Sky & Telescope.

Categories: Astronomy

Cassini Flies Through Enceladus’s Plume

Sky and Telescope - Sat, 31/10/2015 - 03:47

The spacecraft has taken its deepest dive through the water plume leaking from the subsurface ocean of Saturn's moon Enceladus.

Cassini took its penultimate flyby of Saturn's moon Enceladus on October 28, 2015. The spacecraft passed directly through the water vapor and organics plume spewing from the so-called "tiger stripe" fissures at the moon's south pole (up in this image).
NASA / JPL-Caltech / Space Science Institute

On October 28th, the Cassini spacecraft took its deepest dive through the water plume spewing from the south pole of Saturn’s moon Enceladus. It passed only 30 miles (50 kilometers) above the icy surface.

Although the spacecraft has come closer to the moon before — the closest pass was a mere 15 miles up — it’s never passed this directly through the plume before.

Cassini has been on a merry jaunt through the Saturn system for 11 years now. It discovered Enceladus’s marvelous southern plume soon after its arrival. The spritz reaches thousands of miles into space, released from cracks in the moon’s crust called tiger stripes. The material sprayed out is a combination of water and organics, pulled from a subsurface ocean that scientists now think extends globally. The ocean lies maybe 10 to 15 miles below the crust and reaches depths of 30 miles beneath the surface.

The plume’s composition implies there’s hydrothermal activity at work deep inside Enceladus, too, perhaps like that seen on Earth’s ocean floor.

This map shows the active south polar region of Saturn's moon Enceladus. The long, linear, bluish features are the “tiger stripe” fractures, from which a plume of water vapor and other molecules erupts. White circles and crosses represent locations identified by scientists as source locations for dozens of geyser-like jets along the fissures. The red curve is the ground track of Cassini’s October 28, 2015, flyby at the time of the spacecraft's closest approach. Find a global view of Enceladus and its stripes in the JPL Photojournal.
NASA / JPL-Caltech / Space Science Institute

Cassini whizzed over the moon’s surface at 19,000 mph (8 km per second), taking only tens of seconds to complete the pass. That’s too fast to carefully focus on the surface, so instead the team left the apertures of the narrow- and wide-angle cameras open, “shuttering like mad,” said project manager Earl Maize (JPL) in a preview October 26th press briefing. The spacecraft’s trajectory took it right over one of the dozens of active regions found along the tiger stripes, as shown in the diagram at right.

During this flyby Enceladus’s south pole was in shadow, so Cassini saw the surface in saturnshine, only a hundredth as bright as the gleam from a full Moon on Earth.

As project scientist Linda Spilker (JPL) explained during the briefing, the team was looking for three things during this flyby:

  1. How much molecular hydrogen is in the plume. More molecular hydrogen means more hydrothermal activity.
  2. The plume’s chemical composition.
  3. Does the plume come from discrete jets from the moon’s surface, or is the release more like a “curtain” along the full extent of the tiger stripes? The difference matters in that it reveals how the subsurface ocean is connected to the surface — are there individual conduits, or an open crack that goes right into the ocean? That might also tell us how much thermal energy is coming out of fractures.

Although the images are out now, the initial look at these other measurements will take about a week (probably for the Division of Planetary Sciences meeting in mid-November), with more detailed analysis after that.

Fun fact: the amount of plume vapor that Cassini encountered to make all these measurements is equivalent to only a tiny drop of water.

The Final Act

This is an unprocessed image from Cassini's October 28th fly through Enceladus's water plume. The plume is made of water and organics leaked from the moon's subsurface ocean through the "tiger stripe" fissures at the moon's south pole. The line through the top of the image is Saturn's rings.
NASA / JPL-Caltech / Space Science Institute

This flyby was the 21st the spacecraft has made of Enceladus during its mission. It has one more scheduled, in December. After that Cassini will say goodbye to the little moon and enter the final act of its mission. It’ll visit some of Saturn’s ring moons and take a close look at the rings themselves.

Then in April 2017 the spacecraft will nestled itself in the 1,200-mile gap between the innermost ring and the top of Saturn’s atmosphere. It will spend 22 orbits here, looking at the planet’s magnetic field, measuring the mass of the rings and the composition of both ring particles and the upper atmosphere. Then finally, propellant at its end, it’ll plunge into Saturn’s atmosphere and vaporize.


NASA’s put together an Enceladus Final Flybys Toolkit, check it out for more information

The post Cassini Flies Through Enceladus’s Plume appeared first on Sky & Telescope.

Categories: Astronomy

This Week’s Sky at a Glance, October 30 – November 7

Sky and Telescope - Sat, 31/10/2015 - 01:54

Taurid fireball alert. The long-lasting Taurid meteor shower is sparse, but a high proportion of its meteors are bright. This year we're predicted to see more of them than usual, perhaps even a repeat of the 2005 "Halloween fireballs" that made news around the world. The fireball likelihood actually continues well after Halloween, through about November 10th. See the article in the November Sky & Telescope, page 44.

The Venus-Jupiter-Mars show continues before and during dawn. By Saturday morning October 31st, Venus has pulled away from Jupiter and is nearing its conjunction with Mars. (The blue 10° scale is about the width of your fist at arm's length.)

Friday, October 30

• Sometime around 7 or 8 p.m., depending on where you live in your time zone, bright Capella is exactly as high in the northeast as Fomalhaut is in the south.

• On Saturday (North American date), the quarter-mile asteroid 2015 TB145 passes 1.3 lunar distances from Earth. It will reach 10th or 11th magnitude (100 times too faint to see with the unaided eye) as it crosses the northern sky of the early-morning hours. See our article and chart: Close-in Asteroid Offers Halloween Treat.

A webcast of the flyby: Gianluca Masi has marshaled a network of observers to provide real-time views via his Virtual Telescope Project. Watch the webcast starting at 0:00 UT October 31st, which is 8:00 p.m. Friday October 30th EDT.

Saturday, October 31

• The waning gibbous Moon this Halloween doesn't rise until around 9 p.m. (depending on where you are). Once the Moon is well up, look for Orion far to its right, and Gemini's Castor and Pollux off to its left.

• Daylight-saving time ends at 2 a.m. Sunday morning. Clocks fall back an hour (for most of North America).

• In Sunday's dawn, Venus has drawn to within 1.1° of little Mars, even closer than shown above. Mars is only 1/250 as bright. They'll appear closest together on the mornings of Monday and Tuesday, November 2nd and 3rd.

Sunday, November 1

• Before and during dawn Monday, brilliant Venus and faint orange Mars are separated by just 0.8° — less than a fingertip at arm's length. Jupiter looks on from above. In a telescope, Venus is a dazzling white half-moon 22 arcseconds from top to bottom. Mars, currently on the far side of its orbit from us, is a tiny orange blob just 4 arcseconds in diameter.

Monday, November 2

• The last-quarter Moon rises around 11 p.m. tonight, in dim Cancer far below Pollux and Castor. Spot Procyon well to the Moon's upper right. (The Moon is exactly last-quarter at 7:24 a.m. Tuesday the 3rd EST.)

• Before and during dawn Tuesday, Venus and Mars are in conjunction 0.7° apart, with Jupiter above them.

Tuesday, November 3

• Around 9 p.m., depending on where you are, zero-magnitude Capella rises exactly as high in the northeast as zero-magnitude Vega has sunk in the west-northwest. How accurately can you time this event? Astrolabe not required. . . but it would help.

Wednesday, November 4

• Algol should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 8:30 p.m. EST according to its recently revised predictions. Comparison-star chart.

The waning crescent Moon poses with Jupiter on the morning of Friday the 6th, then with Venus and Mars on Saturday the 7th.

Thursday, November 5

• By about 9 p.m. Orion is clearing your eastern horizon (depending on how far east or west you live in your time zone). High above Orion shines orange Aldebaran. Above Aldebaran is the little Pleiades cluster, the size of your fingertip at arm's length. Far left of the Pleiades shines bright Capella.

• The waning Moon shines with Jupiter before and during dawn on Friday morning the 6th, as shown at right. Venus and Mars are below them. Think photo opportunity: Use a tripod, a long lens or zoom, and include a bit of foreground. Send your shot to our online gallery!

Friday, November 6

• In Saturday's dawn, the waning crescent Moon has now stepped down a notch to shine strikingly paired with Venus, as shown at right. Faint Mars close by makes it a triangle. Jupiter shines above them.

Saturday, November 7

• Algol should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 5:20 p.m. EST according to recently revised predictions. Watch it rebrighten for several more hours through the course of the evening. Comparison-star chart.


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.

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 (meaning 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 bright (magnitude –1.0), but it's settling down closer to the east-southeast horizon in bright dawn every day. Look for it there about 30 minutes before sunrise, far beneath and perhaps a bit left of Venus, Jupiter, and Mars. Late in the week, don't confuse it with fainter, twinkly Spica emerging into view nearby. Binoculars help.

Venus, Mars, and Jupiter continue showing off together in the eastern sky before and during dawn. Venus is the brightest at magnitude –4.5. Jupiter is –1.8, and Mars is much fainter at +1.7.

Watch their pattern changing from morning to morning. Venus is descending; Jupiter and Mars are rising. Venus passes close by faint Mars (only 1/250 as bright!) on November 2nd and 3rd, when they'll be 0.8° and 0.7° apart, respectively.

Saturn (magnitude +0.6) disappears very low in the southwest during twilight. Bring binoculars. Don't confuse Saturn with orange Antares twinkling 9° to its left or lower left. Good luck.

Uranus (magnitude +5.7, in Pisces) and Neptune (magnitude +7.8, in Aquarius) are high in the southeast and south, respectively, by 8 p.m. standard time. 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 Daylight Time (EDT) is Universal Time (UT, UTC, or GMT) minus 4 hours. Eastern Standard Time (EST) is UT minus 5 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


The post This Week’s Sky at a Glance, October 30 – November 7 appeared first on Sky & Telescope.

Categories: Astronomy

Tour November’s Sky: Treats at Dawn & Dusk

Sky and Telescope - Fri, 30/10/2015 - 21:32

Bright planets are putting on a stargazing show in the predawn sky, and evenings feature a mythical horse flying upside-down across the sky.

The return to standard time in the U.S., Canada, and Europe means that evening’s twilight comes early — and you can sneak in a little stargazing before dinnertime.

Saturn has ended its long run in the evening sky, so planet-watchers will have to get up early to see the show that continues in predawn skies.

In early November, a crescent Moon joins Jupiter, Venus, and Mars in the eastern sky before dawn.
Sky & Telescope diagram

In early November, Jupiter rises after 3 a.m. (sooner later in the month), and it's followed about a half hour later by brilliant Venus and diminutive Mars. The latter two shine within 1° of each other from the 2nd to 5th, but Venus is much, much brighter. Watch for a thin crescent Moon entering the scene, pairing closely with Jupiter before dawn on the 6th and with Venus and Mars on the 7th.

After evening twilight ends, look high in the southeast for a giant diamond in the sky: the Great Square of Pegasus, the flying horse. The horse is flying upside down; its front legs extend from the top star toward upper right, while its neck and head stretch out and up from the diamond’s right corner.

Keep an eye out for “shooting stars” from a meteor shower known as the Taurids. Usually they’re few and far between, at most a few per hour from dusk to dawn, but many of them create spectacular fireballs. In fact, this year there’s a chance you’ll see a fair number of fireballs throughout the first week of November.

There's lots more to see by eye in the November evening sky. To get a personally guided tour, download our 6½-minute-long stargazing podcast below.

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

The post Tour November’s Sky: Treats at Dawn & Dusk appeared first on Sky & Telescope.

Categories: Astronomy

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