Terry's Astronomy Thread.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 3, 2013

-In this coldest time of the year, the dim Little Dipper hangs straight down from Polaris after dinnertime as if from a nail on the cold north wall of the sky.

-Algol should be at minimum light for a couple hours centered on 7:52 p.m. EST.

Astro Picture of the Day:
January 3, 2013

Source:
Open clusters of stars can be near or far, young or old, and diffuse or compact. Found near the plane of our Milky Way galaxy, they contain from 100 to 10,000 stars, all of which formed at nearly the same time. Bright blue stars frequently distinguish younger open clusters. M35, on the upper left, is relatively nearby at 2800 light years distant, relatively young at 150 million years old, and relatively diffuse, with about 2500 stars spread out over a volume 30 light years across. An older and more compact open cluster, NGC 2158, is at the lower right. NGC 2158 is four times more distant than M35, over 10 times older, and much more compact with many more stars in roughly the same volume of space. NGC 2158's bright blue stars have self-destructed, leaving cluster light to be dominated by older and yellower stars. Both clusters are seen toward the constellation of Gemini.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 4, 2013

-The latest sunrise of the year happens this morning (at 40° north latitude).

-Last-quarter Moon tonight (exact at 10:58 p.m. EST). The Moon, between Corvus and the head of Virgo, rises around 11 or midnight. By dawn Saturday morning, the Moon is high in the south with Spica and Saturn to its left, as shown here.

Astro Picture of the Day:
January 4, 2013

Source:
Tycho crater's central peak complex casts a long, dark shadow near local sunrise in this spectacular lunarscape. The dramatic oblique view was recorded on June 10, 2011 by the Lunar Reconnaissance Orbiter. Shown in amazing detail, boulder strewn slopes and jagged shadows appear in the highest resolution version at 1.5 meters per pixel. The rugged complex is about 15 kilometers wide, formed in uplift by the giant impact that created the well-known ray crater 100 million years ago. The summit of its central peak reaches 2 kilometers above the Tycho crater floor. The highest resolution image can be found by clicking this link.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 5, 2013

-Before dawn Sunday morning, Spica shines to the upper right of the waning Moon, and Saturn shines to the Moon's upper left, as shown here.

-Mercury is hidden in the glare of the Sun.

-Venus (magnitude –3.9) appears lower in the dawn each morning. Look for it above the southeast horizon about 45 minutes before your local sunrise.



Astro Picture of the Day:
January 5, 2013

Source:
Get out your red/blue glasses and float next to Helene, small, icy moon of Saturn. Appropriately named, Helene is one of four known Trojan moons, so called because it orbits at a Lagrange point. A Lagrange point is a gravitationally stable position near two massive bodies, in this case Saturn and larger moon Dione. In fact, irregularly shaped ( about 36 by 32 by 30 kilometers) Helene orbits at Dione's leading Lagrange point while brotherly ice moon Polydeuces follows at Dione's trailing Lagrange point. The sharp stereo anaglyph was constructed from two Cassini images (N00172886, N00172892) captured during a close flyby in 2011. It shows part of the Saturn-facing hemisphere of Helene mottled with craters and gully-like features.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 6, 2013

-At this coldest time of the year, Sirius rises around 7 p.m. (depending on how far east or west you live in your time zone). Orion's three-star Belt points down almost to Sirius's rising place; watch for it there. Once Sirius is up, it twinkles slowly and deeply through the thick layers of low atmosphere, then faster and more shallowly as it gains altitude. Its flashes of color also speed up and blend into shimmering white as the star climbs to shine through thinner air.

-Watch Jupiter gradually creeping toward a better lineup between Aldebaran and the Pleiades. It won't quite get there, however. Instead it will gradually stop and reverse direction at the end of January, just short of forming a straight line. (The 10° scale is about the width of your fist held at arm's length.)

Astro Picture of the Day:
January 6, 2013

Source:
In silhouette against a crowded star field toward the constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across this gorgeous telescopic portrait. Known as a cometary globule, the swept-back cloud, extending from the lower right to the head (top of the tower) left and above center, is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231, off the upper edge of the scene. That energetic ultraviolet light also powers the globule's bordering reddish glow of hydrogen gas. Hot stars embedded in the dust can be seen as bluish reflection nebulae. This dark tower, NGC 6231, and associated nebulae are about 5,000 light-years away.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 7, 2013

-As dawn begins to brighten on Tuesday morning, spot the waning crescent Moon in the southeast. Below it is Antares, a summer-evening star just beginning its months-long trek backward through the night. Much farther lower left of the Moon, Venus rises. Higher in the south are Saturn and, two fists to Saturn's right, Spica.

The waning crescent Moon appears lower each morning until dawn on Thursday, when it forms a spectacular pair with Venus very low in the southeast.

Astro Picture of the Day:
January 7, 2013

Source:
AE Aurigae is called the flaming star. The surrounding nebula IC 405 is named the Flaming Star Nebula and the region seems to harbor smoke, but there is no fire. Fire, typically defined as the rapid molecular acquisition of oxygen, happens only when sufficient oxygen is present and is not important in such high-energy, low-oxygen environments. The material that appears as smoke is mostly interstellar hydrogen, but does contain smoke-like dark filaments of carbon-rich dust grains. The bright star AE Aurigae, visible near the nebula center, is so hot it is blue, emitting light so energetic it knocks electrons away from atoms in the surrounding gas. When an atom recaptures an electron, light is emitted creating the surrounding emission nebula. In this cosmic portrait, the Flaming Star nebula lies about 1,500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga).

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 8, 2013

-Jupiter's moon Io crosses Jupiter's face from 8:03 to 10:13 p.m. EST, followed by Io's tiny black shadow from 8:55 to 11:06 p.m. EST. Jupiter's Great Red Spot transits the planet's central meridian around 2:02 a.m. Wednesday morning EST.

-Mars (magnitude +1.2, in Sagittarius) still glimmers low in the southwest in the fading glow of sunset. Don't confuse it with Fomalhaut far to its left.

Astro Picture of the Day:
January 8, 2013

Source:
How was the unusual Red Rectangle nebula created? At the nebula's center is an aging binary star system that surely powers the nebula but does not, as yet, explain its colors. The unusual shape of the Red Rectangle is likely due to a thick dust torus which pinches the otherwise spherical outflow into tip-touching cone shapes. Because we view the torus edge-on, the boundary edges of the cone shapes seem to form an X. The distinct rungs suggest the outflow occurs in fits and starts. The unusual colors of the nebula are less well understood, however, and current speculation holds that they are partly provided by hydrocarbon molecules that may actually be building blocks for organic life. The Red Rectangle nebula lies about 2,300 light years away towards the constellation of the Unicorn (Monoceros). The nebula is shown above in unprecedented detail as captured recently by the Hubble Space Telescope. In a few million years, as one of the central stars becomes further depleted of nuclear fuel, the Red Rectangle nebula will likely bloom into a planetary nebula. A diagram that may help show how the current nebulae can look like this is below:

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 9, 2013

-The waning crescent Moon appears lower each morning until dawn on Thursday, when it forms a spectacular pair with Venus very low in the southeast.

-Venus (magnitude –3.9) appears lower in the dawn each morning. Look for it above the southeast horizon about 45 minutes before your local sunrise.

Astro Picture of the Day:
January 9, 2013

Source:
Normally faint and elusive, the Jellyfish Nebula is caught in this alluring telescopic view. Drifting near bright star Eta Geminorum, at the foot of a celestial twin, the Jellyfish Nebula is seen dangling tentacles from the bright arcing ridge of emission left of center. In fact, the cosmic jellyfish is part of bubble-shaped supernova remnant IC 443, the expanding debris cloud from a massive star that exploded. Light from the explosion first reached planet Earth over 30,000 years ago. Like its cousin in astrophysical waters the Crab Nebula supernova remnant, IC 443 is known to harbor a neutron star, the remnant of the collapsed stellar core. The Jellyfish Nebula is about 5,000 light-years away. At that distance, this image would be about 100 light-years across.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 10, 2013

-Saturn (magnitude +0.6, in Libra) rises in the east-southeast around 2 a.m. local time. By the beginning of dawn it's fairly high in the southeast. That's the best time to get your telescope on it. Saturn's rings are tilted 19° to our line of sight, the widest open they've been in seven years.

Astro Picture of the Day:
January 10, 2013

Source:
Cosmic bullets pierce the outskirts of the Orion Nebula some 1500 light-years distant in this sharp infrared close-up. Blasted out by energetic massive star formation the bullets, relatively dense, hot gas clouds about ten times the size of Pluto's orbit, are blue in the false color image. Glowing with the light of ionized iron atoms they travel at speeds of hundreds of kilometers per second, their passage traced by yellowish trails of the nebula's shock-heated hydrogen gas. The cone-shaped wakes are up to a fifth of a light-year long. The detailed image was created using the 8.1 meter Gemini South telescope in Chile with a newly commisioned adaptive optics system (GeMS). Achieving a larger field of view than previous generation adaptive optics, GeMS uses five laser generated guide stars to help compensate for the blurring effects of planet Earth's atmosphere.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 11, 2013

-In early evening at this time of year, the Great Square of Pegasus balances on one corner high in the west. The vast Andromeda-Pegasus constellation complex runs all the way from near the zenith (Andromeda's foot) down through the Great Square (Pegasus's body) to low in the west (Pegasus's nose).

-New Moon (exact at 2:44 p.m. EST).

Astro Picture of the Day:
January 11, 2013

Source:
How do clusters of galaxies form and evolve? To help find out, astronomers continue to study the second closest cluster of galaxies to Earth: the Fornax cluster, named for the southern constellation toward which most of its galaxies can be found. Although almost 20 times more distant than our neighboring Andromeda galaxy, Fornax is only about 10 percent further that the better known and more populated Virgo cluster of galaxies. Fornax has a well-defined central region that contains many galaxies, but is still evolving. It has other galaxy groupings that appear distinct and have yet to merge. Seen here, almost every yellowish splotch on the image is an elliptical galaxy in the Fornax cluster. The picturesque barred spiral galaxy NGC 1365 visible on the lower right is also a prominent Fornax cluster member.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 12, 2013

-As twilight turns to night, look low in the northwest for Vega. To its upper left, by two or three fists at arm's length, shines Deneb. Deneb is the head of the big Northern Cross, which is now swinging down and soon will stand nearly upright on the northwest horizon (as seen from mid-northern latitudes).

-The crescent Moon marches higher each evening as it waxes thicker farther away from the Sun. Use the Moon to locate faint little Mars.

News Posted Today:
January 12, 2013
NGC 6872: Largest Spiral Galaxy Known


Astro Picture of the Day:
January 12, 2013

Source:
How common are Earth-sized planets? Quite common, according to extrapolations from new data taken by NASA's orbiting Kepler spacecraft. Current computer models are indicating that at least one in ten stars are orbited by an Earth-sized planet, making our Milky Way Galaxy the home to over ten billion Earths. Unfortunately, this estimate applies only to planets effectively inside the orbit of Mercury, making these hot-Earths poor vacation opportunities for humans. This histogram depicts the estimated fraction of stars that have close orbiting planets of various sizes. The number of Sun-like stars with Earth-like planets in Earth-like orbits is surely much less, but even so, Kepler has also just announced the discovery of four more of those.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 13, 2013

-In twilight this evening, look below the waxing crescent Moon in the west to see if you can still spot faint little Mars, as shown here. Mars has been hanging in there in twilight ever since August! but is now gradually creeping lower week by week.

Astro Picture of the Day:
January 13, 2013

Source:
Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in the sharp Hubble view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 14, 2013

-Before moonlight returns in force to wash out low-surface-brightness telescopic objects, try tonight for the Bubble and Pac-Man Nebulae in Cassiopeia.

-Jupiter (magnitude –2.7, in Taurus) is the first "star" to appear in the eastern sky after sundown. It dominates the high southeast after dusk, with orange Aldebaran below it and the Pleiades over it as shown below. They tilt around and pass highest in the south around 8 or 9 p.m. local time. In a telescope Jupiter is still about 45 arcseconds wide.

Astro Picture of the Day:
January 14, 2013

Source:
In this celestial still life composed with a cosmic brush, dusty nebula NGC 2170 shines left of image center. Reflecting the light of nearby hot stars, NGC 2170 is joined by other bluish reflection nebulae, a red emission region, many dark absorption nebulae, and a backdrop of colorful stars. Like the common household items still life painters often choose for their subjects, these clouds of gas, dust, and hot stars are also commonly found in this setting - a massive, star-forming molecular cloud in the constellation Monoceros. The giant molecular cloud, Mon R2, is impressively close, estimated to be only 2,400 light-years or so away. At that distance, this canvas would be over 40 light-years across.

[YoshL]

Re: Terry's Astronomy Thread.

If this doesn't win best thread 2012 i'm gonna punch a baby

[Fluvs]

Re: Terry's Astronomy Thread.

If this doesn't win best thread 2012 i'm gonna punch a baby

So serious yikes a baby that's so mean :c

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
January 15, 2013

-Mercury is hidden in conjunction with the Sun.

-Saturn (magnitude +0.6, in Libra) rises in the east-southeast around 1 or 2 a.m. local time. By the beginning of dawn it's fairly high in the southeast. That's the best time to get your telescope on it. Saturn's rings are tilted 19° to our line of sight, the widest open they've been for seven years.

Astro Picture of the Day:
January 15, 2013

Source:
Sometimes, the Sun itself seems to dance. On just this past New Year's Eve, for example, NASA's Sun-orbiting Solar Dynamic Observatory spacecraft imaged an impressive prominence erupting from the Sun's surface. The dramatic explosion was captured in ultraviolet light in the above time lapse video covering four hours. Of particular interest is the tangled magnetic field that directs a type of solar ballet for the hot plasma as it falls back to the Sun. The scale of the disintegrating prominence is huge - the entire Earth would easily fit under the flowing curtain of hot gas. A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. The energy mechanism that creates a solar prominence is still a topic of research. As the Sun nears Solar Maximum this year, solar activity like eruptive prominences should be common.