Terry's Astronomy Thread.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
September 30, 2012

-Jupiter's Great Red Spot (currently pale orange-tan) should cross Jupiter's central meridian around 12:39 a.m. EDT tonight (9:39 p.m. PDT).

-Mars (magnitude +1.2, in Libra) remains low in the southwest in evening twilight. Don't confuse it with twinklier orange Antares ("Anti-Mars") to its left or upper left. The gap between them shrinks from 16° to 11° this week. They're nearly the same brightness.

Astro Picture of the Day:
September 30, 2012

Source:
Galaxies don't normally look like this. NGC 6745 actually shows the results of two galaxies that have been colliding for only hundreds of millions of years. Just off the above digitally sharpened photograph to the lower right is the smaller galaxy, moving away. The larger galaxy, pictured above, used to be a spiral galaxy but now is damaged and appears peculiar. Gravity has distorted the shapes of the galaxies. Although it is likely that no stars in the two galaxies directly collided, the gas, dust, and ambient magnetic fields do interact directly. In fact, a knot of gas pulled off the larger galaxy on the lower right has now begun to form stars. NGC 6745 spans about 80 thousand light-years across and is located about 200 million light-years away.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 1, 2012

-Altair is the bright star high in the south at nightfall this week. Look for little Tarazed (Gamma Aquilae) to its upper right, and fainter Beta Aquilae a little farther to its lower left. Altair is just 17 light-years away. It's spinning so fast that it's a flattened ellipsoid, not a sphere.

-Saturn (magnitude +0.7) is becoming lost deep in the sunset, far to the lower right of Mars.

Astro Picture of the Day:
October 1, 2012

Source:
Could this dim spot brighten into one of the brightest comets ever? It's possible. Alternatively, the comet could break up when it gets closer to the Sun, or brighten much more modestly. Sky enthusiasts the world over are all abuzz, though, from the more optimistic speculations -- that the newly discovered C/2012 S1 (ISON) could develop a spectacular tail or briefly approach the brightness of the full Moon toward the end of 2013. Comet ISON currently is very faint but is just visible at magnitude 18 in the above image. The comet, discovered just over a week ago from Russia by Vitali Nevski (Belarus) and Artyom Novichonok (Russia), is currently falling toward the Sun from between the orbits of Jupiter and Saturn. In early 2013 October it will pass very near Mars and possibly be visible to rovers and orbiting spacecraft. Comet ISON appears on course to achieve sungrazer status as it passes within a solar diameter of Sun's surface in late 2013 November. Whatever survives will then pass nearest the Earth in late 2013 December. Astronomers around the world will be tracking this large dirty snowball closely to better understand its nature and how it might evolve during the next 15 months.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 2, 2012

-As dawn begins to break Wednesday morning, look east for dazzling Venus. Just 0.2° from it or less (as seen from the Americas) is Regulus, less than 1% as bright. You may need binoculars to separate Regulus from Venus's glare. A telescope provides a fine view, though Venus itself is currently an undistinguished gibbous disk just 16 arcseconds in diameter.

-Venus (magnitude –4.1, in Leo) rises in darkness around 4 a.m. daylight saving time (depending on where you live), emerging above the east-northeast horizon two hours before the first glimmer of dawn. By dawn it's blazing high in the east.

Astro Picture of the Day:
October 2, 2012

Source:
Fresh evidence of an ancient stream has been found on Mars. The robotic rover Curiosity has run across unusual surface features that carry a strong resemblance to stream banks on Earth. Visible in the above image, for example, is a small overhanging rock ledge that was quite possibly created by water erosion beneath. The texture of the ledge appears to be a sedimentary conglomerate, the dried remains of many smaller rocks stuck together. Beneath the ledge are numerous small pebbles, possibly made smooth by tumbling in and around the once-flowing stream. Pebbles in the streambed likely fell there as the bank eroded. Circled at the upper right is a larger rock possibly also made smooth by stream erosion. Curiosity has now discovered several indications of dried streambeds on Mars on its way to its present location where it will be exploring the unusual conjunction of three different types of landscape.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 3, 2012

-The Pleiades sparkle to the left of the waning gibbous Moon late this evening, as shown at lower right.

-Jupiter (magnitude –2.5, in Taurus) rises in the east-northeast around 10 p.m. daylight saving time. Once it's clear of the horizon, look for fainter orange Aldebaran twinkling 8° to its right and Beta Tauri (Elnath) a trace farther to Jupiter's left. By the beginning of dawn, this lineup-of-three stands high and diagonal in the south.

Astro Picture of the Day:
October 3, 2012

Source:
Sometimes it's hard to believe what you see in the sky. During the Shelios Expedition to Greenland in late August, even veteran sky enthusiasts saw auroras so colorful, so fast changing, and so unusual in form that they could remember nothing like it. As the ever changing auroras evolved, huge shapes spread across the sky morphed from one familiar form into another, including what looked to be the head of a goat (shown above), the head of an elephant, a strange green-tailed comet, and fingers on a celestial hand. Even without the aurora, the sky would be notable for the arching band of our Milky Way Galaxy and the interesting field of stars, nebulas, and galaxies. In contrast, in the foreground is a farm house in Tasiusaq, Kujalleq. Greenland. The Shelios project exists not only to observe auroras but to motivate students to consider a career in science.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 4, 2012

-Late this evening, look for Aldebaran below the Moon and bright Jupiter to the Moon's lower left, as shown below.

Astro Picture of the Day:
October 4, 2012
[center]
Source:
A mere seven hundred light years from Earth, in the constellation Aquarius, a sun-like star is dying. Its last few thousand years have produced the Helix Nebula (NGC 7293), a well studied and nearby example of a Planetary Nebula, typical of this final phase of stellar evolution. A total of 58 hours of exposure time have gone in to creating this deep view of the nebula. Accumulating narrow band data from emission lines of hydrogen atoms in red and and oxygen atoms in blue-green hues, it shows remarkable details of the Helix's brighter inner region, about 3 light-years across, but also follows fainter outer halo features that give the nebula a span of well over six light-years. The white dot at the Helix's center is this Planetary Nebula's hot, central star. A simple looking nebula at first glance, the Helix is now understood to have a surprisingly complex geometry.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 5, 2012

-Jupiter comes up over the east-northeast horizon around 9:30 or 10 tonight, followed a half hour later by the nearly last-quarter Moon. They rise higher as night grows late, as shown at lower right.

-Jupiter's satellite Ganymede slowly disappears into eclipse by Jupiter's shadow at 12:32 a.m. EDT tonight a little west of Jupiter, then emerges from eclipse at 2:31 a.m. EDT barely west of the planet's edge. Subtract 3 hours for PDT. A small telescope is all you need.

Astro Picture of the Day:
October 5, 2012

Source:
What's happening behind that mountain? A convergence of variable sky spectacles. One night in mid-September near Tromsø, Norway, high red aurora could be seen shimmering through lower green aurora in a way that created a striking and somewhat unusual violet glow. Suddenly, though, the sky flashed with the brightest fireball the astrophotographer had ever seen, as a small pebble from outer space violently crashed into the Earth's atmosphere. The glow illuminated the distant mountain peak known as Otertinden of the Lyngen Alps. The bright meteor, which coincidently disappeared behind the same mountain, was also reflected in the foreground Signalelva River. Although you might consider yourself lucky to see either an aurora or a bright meteor, pictures of them together have been recorded several times previously.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 6, 2012

-The bright eclipsing variable star Algol should be in one of its periodic dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 11:32 p.m. EDT (8:32 p.m. PDT). Algol takes several additional hours to fade and to rebrighten. Click on the chart at right.

-Glance up at Algol at any random time, and you have a 1 in 30 chance of catching it at least 1 magnitude fainter than normal.

Astro Picture of the Day:
October 6, 2012

Source:
Near the center of this sharp cosmic portrait, at the heart of the Orion Nebula, are four hot, massive stars known as the Trapezium. Gathered within a region about 1.5 light-years in radius, they dominate the core of the dense Orion Nebula Star Cluster. Ultraviolet ionizing radiation from the Trapezium stars, mostly from the brightest star Theta 1 Orionis C powers the complex star forming region's entire visible glow. About three million years old, the Orion Nebula Cluster was even more compact in its younger years and a recent dynamical study indicates that runaway stellar collisions at an earlier age may have formed a black hole with more than 100 times the mass of the Sun. The presence of a black hole within the cluster could explain the observed high velocities of the Trapezium stars, The Orion Nebula's distance of some 1500 light-years would make it the closest known black hole to planet Earth.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Note: The main OP is currently unable to be updated because it has grown too large for vbz to handle. I'll have a work around set by the end of Thanksgiving for Canadians, but it looks like the OP gets a little hard to edit after 52,000 words and over 350,000 characters.

What's in the sky tonight?
October 7, 2012

-Vega remains very high in the west after nightfall this week. Look for fainter stars of the little constellation Lyra extending to its left, by roughly a fist-width at arm's length.

-Jupiter's Great Red Spot should cross the planet's central meridian tonight around 1:25 a.m. EDT.

Astro Picture of the Day:
October 7, 2012

Source:
The 16th century Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two fuzzy cloud-like objects easily visible to southern hemisphere skygazers are known as the Clouds of Magellan, now understood to be satellite galaxies of our much larger, spiral Milky Way galaxy. About 160,000 light-years distant in the constellation Dorado, the Large Magellanic Cloud (LMC) is seen here in a remarkably deep, colorful composite image, starlight from the central bluish bar contrasting with the telltale reddish glow of ionized atomic hydrogen gas. Spanning about 15,000 light-years or so, it is the most massive of the Milky Way's satellite galaxies and is the home of the closest supernova in modern times, SN 1987A. The prominent patch at top left is 30 Doradus, also known as the magnificent Tarantula Nebula. The giant star-forming region is about 1,000 light-years across.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 8, 2012

-Even as the stars begin to come out in twilight, Cassiopeia is already higher in the northeast now than the sinking Big Dipper is in the northwest. Cassiopeia's broad W pattern is standing on end.

-Mars (magnitude +1.2, in Libra) remains low in the southwest in evening twilight. Don't confuse it with twinklier orange Antares ("Anti-Mars") to its left. The gap between them shrinks from 11° to 7° this week. They're nearly the same brightness.

Astro Picture of the Day:
October 8, 2012

Source:
Ghostly in appearance, Abell 39 is a remarkably simple, spherical nebula about five light-years across. Well within our own Milky Way galaxy, the cosmic sphere is roughly 7,000 light-years distant toward the constellation Hercules. Abell 39 is a planetary nebula, formed as a once sun-like star's outer atmosphere was expelled over a period of thousands of years. Still visible, the nebula's central star is evolving into a hot white dwarf. Although faint, the nebula's simple geometry has proven to be a boon to astronomers exploring the chemical abundances and life cycles of stars. In this deep image recorded under dark night skies, very distant background galaxies can be found - some visible right through the nebula itself.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 9, 2012

-Algol should be near minimum light for a couple hours centered on 8:21 p.m. EDT.

-Jupiter (magnitude –2.6, in Taurus) rises in the east-northeast around 9 or 10 p.m. daylight saving time. Once it's clear of the horizon, look for fainter orange Aldebaran twinkling 8° to its right and Beta Tauri (Elnath) a similar distance to Jupiter's left. By dawn this lineup-of-three stands high and almost vertical in the southwest.

Astro Picture of the Day:
October 9, 2012

Source:
It's easy to get lost following the intricate filaments in this detailed mosaic image of faint supernova remnant Simeis 147 (S147). Also cataloged as Sh2-240, it covers nearly 3 degrees or 6 full moons on the sky. That's about 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. Anchoring the frame at the right, bright star Elnath (Beta Tauri) is seen towards the boundary of the constellations Taurus and Auriga, almost exactly opposite the galactic center in planet Earth's sky. This sharp composite includes image data taken through a narrow-band filter to highlight emission from hydrogen atoms tracing the shocked, glowing gas. The supernova remnant has an estimated age of about 40,000 years, meaning light from the massive stellar explosion first reached Earth 40,000 years ago. But the expanding remnant is not the only aftermath. The cosmic catastrophe also left behind a spinning neutron star or pulsar, all that remains of the original star's core.

[Bluearrowll]

Re: Terry's Astronomy Thread.

Over 7,000 (32.87 visitors / day) views and happy 7 months!

What's in the sky tonight?
October 10, 2012

-Jupiter's Great Red Spot should cross the planet's central meridian around 10:54 p.m. EDT.

-In early dawn for the next couple mornings, watch the waning crescent Moon passing to the right of Regulus, then Venus.

-Saturn is lost in the sunset.

Astro Picture of the Day:
October 10, 2012

Source:
How could a galaxy become shaped like a ring? Even more strange: how could two? The rim of the blue galaxy pictured on the right shows an immense ring-like structure 30,000 light years in diameter composed of newly formed, extremely bright, massive stars. This blue galaxy is part of the interacting galaxy system known as Arp 147, and shows a ring because it has recently collided with the other galaxy in the frame, the red galaxy on the left. Unusually, even this red galaxy shows a ring like band, although it is seen nearly edge-on. When galaxies collide, they pass through each other - their individual stars rarely come into contact. Clouds of interstellar gas and dust become condensed, causing a wave of star formation to move out from the impact point like a ripple across the surface of a pond. The above image was taken last week by NASA's Hubble Space Telescope to demonstrate the ability of its Wide Field Planetary Camera 2 after some recent technical difficulties.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 11, 2012

-Bright Arcturus is twinkling lower in the western twilight every week, riding off into the sunset for this year. How many more weeks can you follow it down? Well to its right, look for the Big Dipper lying down low.

-Uranus (magnitude 5.7, at the Pisces-Cetus border) and Neptune (magnitude 7.8, in Aquarius) are in the southeast to south during evening

Astro Picture of the Day:
October 11, 2012

Source:
North America at night is easy to recognize in this view of our fair planet from orbit, acquired by the Suomi-NPP satellite on October 8. The spectacular waves of visible light emission rolling above the Canadian provinces of Quebec and Ontario in the upper half of the frame are the Aurora Borealis or northern lights. Encircling the poles and extending to lower latitudes, impressive aurorae seen during the past few days are due to strong geomagnetic storms. The storms were triggered by a solar coronal mass ejection on October 4/5, impacting Earth's magnetosphere some three days later. The curtains of light, shining well over 100 kilometers above the surface, are formed as charged particles accelerated in the magnetosphere excite oxygen and nitrogen in the upper atmosphere.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 12, 2012

-Jupiter's Great Red Spot should cross the planet's central meridian tonight around 12:47 a.m. Saturday morning EDT.

-Before dawn Saturday morning, along a path from Southern California through central Texas, the faint asteroid 371 Bohemia should occult an 8.9-magnitude star high in the sky near the Beehive Cluster in Cancer. The occultation should last up to 2 seconds. Details here: http://www.asteroidoccultation.com/2..._371_28129.htm

Astro Picture of the Day:
October 12, 2012

Source:
In myth, Atlas holds up the heavens, but in this scene they seem to pivot around a lighthouse beacon. Photographed with a camera fixed to a tripod, the well-planned 30 minute exposure records star trails in the northern sky, reflecting the daily rotation of planet Earth. Hidden behind the top of the prominent Nauset Lighthouse on Cape Cod, Massachusetts, USA, the North Celestial Pole is at the center of all the star trail arcs. Making a complete circle, 360 degrees, in 24 hours, the star trail arcs cover 15 degrees each hour or 7.5 degrees in thirty minutes. Foreground lighting is courtesy of September 23rd's first quarter moonlight.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 13, 2012

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

-Venus hangs below Leo in the morning, who is now rising from a summer sleep.



Astro Picture of the Day:
October 13, 2012

Source:
Spiky stars and spooky shapes abound in this deep cosmic skyscape. Its well-composed field of view covers about 2 Full Moons on the sky toward the constellation Pegasus. Of course the brighter stars show diffraction spikes, the commonly seen effect of internal supports in reflecting telescopes, and lie well within our own Milky Way galaxy. The faint but pervasive clouds of interstellar dust ride above the galactic plane and dimly reflect the Milky Way's combined starlight. Known as high latitude cirrus or integrated flux nebulae they are associated with molecular clouds. In this case, the diffuse cloud cataloged as MBM 54, less than a thousand light-years distant, fills the scene. Other galaxies far beyond the Milky Way are visible through the ghostly apparitions, including the striking spiral galaxy NGC 7497 some 60 million light-years away. Seen almost edge-on near the center of the field, NGC 7497's own spiral arms and dust lanes echo the colors of the Milky Way's stars and dust.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
October 14, 2012

-Jupiter's moon Io disappears into eclipse by Jupiter's shadow, barely west of the planet, around 1:51 a.m. Monday morning EDT; 10:51 p.m. Sunday evening PDT. By then Jupiter's Great Red Spot will be nearing the planet's central meridian — which it crosses about 19 minutes later.

-Mars (magnitude +1.2, in Scorpius) remains low in the southwest in evening twilight, close to twinklier orange Antares ("Anti-Mars") to its left or lower left. The gap between them shrinks from 7° to 3½° this week. They're nearly the same brightness.

Astro Picture of the Day:
October 14, 2012

Source:
What did the first galaxies look like? To help answer this question, the Hubble Space Telescope has just finished taking the eXtreme Deep Field (XDF), the deepest image of the universe ever taken in visible light. Pictured above, the XDF shows a sampling of some of the oldest galaxies ever seen, galaxies that formed just after the dark ages, 13 billion years ago, when the universe was only a few percent of its present age. The Hubble Space Telescope's ACS camera and the infrared channel of the WFPC3 camera took the image. Combining efforts spread over 10 years, the XDF is more sensitive, in some colors, than the original Hubble Deep Field (HDF), the Hubble Ultra Deep Field (HUDF) completed in 2004, and the HUDF Infrared completed in 2009. Astronomers the world over will likely study the XDF for years to come to better understand how stars and galaxies formed in the early universe.

A higher resolution image: