Terry's Astronomy Thread.

[Bluearrowll]

Re: Terry's Astronomy Thread.

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

-On Monday morning before sunrise, look below bright Venus in the east for the thin waning Moon with Saturn to its left, as shown here. Binoculars will help. Saturn is just beginning its year-long 2012–13 apparition.

Astro Picture of the Day:
November 11, 2012

Source:
Just before the Sun blacks out, something strange occurs. As the Moon moves to completely cover the Sun in a total solar eclipse - like the one set to occur over parts of Australia on Tuesday - beads of bright sunlight stream around the edge of the Moon. This effect, known as Baily's beads, is named after Francis Baily who called attention to the phenomenon in 1836. Although, the number and brightness of Baily's beads used to be unpredictable, today the Moon is so well mapped that general features regarding Baily's beads are expected. When a single bead dominates, it is called the diamond ring effect, and is typically seen just before totality. Pictured above, horizontally compressed, a series of images recorded Baily's beads at times surrounding the 2008 total solar eclipse visible from Novosibirsk, Russia. At the end of totality, as the Sun again emerges from behind the moon, Baily's beads may again be visible - but now on the other side of the Moon.

[Bluearrowll]

Re: Terry's Astronomy Thread.

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

-Fomalhaut, the "Autumn Star," culminates (reaches its highest point due south) not long after dark now. The western side of the Great Square of Pegasus, high above, points almost down to it. The other side of the Great Square points down roughly to Beta Ceti (Diphda or Deneb Kaitos), not quite so far.

Astro Picture of the Day:
November 12, 2012

Source:
The Kreutz Group of comets has resulted in more than ten bright comets and many hundreds of small fragments that have only been observed by dedicated solar satellites. The last Great Sungrazer was White-Ortiz-Bolelli seen in 1970. The attached shows Comet White-Ortiz-Bolelli (S&T july 1970, p16) and the new record holder, Comet Lovejoy, photographed Christmas eve from Wagga Wagga, Australia, by Dr Graeme White; the co-discover of Comet White-Ortiz-Bolelli (some 40 years earlier) and Michael Maher. Note the striking similarity of the structure – these two comets are truly sisters. The photo was taken at Christmas eve, at 04:00 local Summer time using a Nikon D90 at 18 mm, f/3.5, maximum ISO and with full noise reduction. Losmandy mount.

[Bluearrowll]

Re: Terry's Astronomy Thread.

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

-Orion is up in the east by about 9 p.m. now, depending on where you live in your time zone. Orion's three-star Belt is nearly vertical. Orange Betelgeuse is to the Belt's left and white Rigel is to its right. Earlier in the evening, keep watch for Betelgeuse rising far below Jupiter.



On 2012 November 13/14, a total eclipse of the Sun is visible from within a narrow corridor that traverses Earth's southern Hemisphere. The path of the Moon's umbral shadow begins in northern Australia and crosses the South Pacific Ocean with on other no landfall. The Moon's penumbral shadow produces a partial eclipse visible from a much larger region covering Australia, New Zealand, and the South Pacific.

For those traveling to Australia for the eclipse, please note that the eclipse occurs on the morning of Nov. 14 local time.

The total solar eclipse of 2012 occurs at the Moon's ascending node in central Libra. The path of the Moon's umbral shadow crosses the South Pacific Ocean where it makes no landfall except for northern Australia. The Moon's penumbral shadow produces a partial eclipse visible from a much larger region covering the South Pacific (including Australia and New Zealand), southern South America, and part of Antarctica (Figure 4: If you live in the green areas, you can see at least some of the eclipse! ).

The central eclipse path begins in Australia's Garig Ganak Barlu National Park in the Northern Territory about 250 kilometres east of Darwin at 20:35 UT (Figure 5: an expanded view of the Austrailian region that sees totality. ). Traveling southeast, the umbral shadow quickly crosses the Gulf of Carpentaria and reaches the Cape York Peninsula at 20:37 UT.

The first and only populated region in the path lies along the east coast of Queensland. Gateway to Australia's Great Barrier Reef, Cairns is about 30 kilometres south of the central line. Its residents and visitors will enjoy an early morning total eclipse lasting 2 minutes with the Sun just 14° above the eastern horizon. Observers on the central line can eek out another 5 seconds of totality, but local weather conditions will play a far greater role in choosing a viewing site than a few seconds of totality.

After leaving Australia, the umbral shadow glides over the ocean, undisturbed by further landfall for the remainder of its track. The instant of greatest eclipse [1] occurs in the South Pacific at 22:11:48 UT. At this instant, the axis of the Moon's shadow passes closest to Earth's centre. The maximum duration of totality is 4 minutes 2 seconds, the Sun's altitude is 68°, and the path width is 179 kilometres. Continuing across the vast South Pacific, the umbral shadow's path ends about 800 kilometres west of Chile at 23:48 UT.

Astro Picture of the Day:
November 13, 2012

Source:
Which feature takes your breath away first in this encompassing panorama of land and sky? The competition is strong with a waterfall, meteor, starfield, and even a moonbow all vying for attention. It is interesting to first note, though, what can't be seen -- a rising moon on the other side of the camera. The bright moon not only illuminated this beautiful landscape in Queensland, Australia last June, but also created the beautiful moonbow seen in front of Wallaman Falls. Just above the ridge in the above image is the horizontal streak of an airplane. Toward the top of the frame is the downward streak of a bright meteor, a small pebble from across our Solar System that lit up as it entered the Earth's atmosphere. Well behind the meteor are numerous bright stars and nebula seen toward the center of our Galaxy. Finally, far in the background, is the band of our Milky Way Galaxy, running diagonally from the lower left to the upper right in the image but also circling the entire sky.

[Bluearrowll]

Re: Terry's Astronomy Thread.

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

-Vega is the brightest star in the west in early evening. The brightest far left of it, in the southwest, is Altair. Altair's 3rd-magnitude companion Gamma Aquilae (Tarazed), a finger's width at arm's length from it, is now to Altair's right.

-Saturn (magnitude +0.6, in Virgo) is emerging into dawn view low in the east. Look for it below or lower left of bright Venus. They appear closer together every day.

Astro Picture of the Day:
November 14, 2012

Source:
This image of Saturn could not have been taken from Earth. No Earth based picture could possibly view the night side of Saturn and the corresponding shadow cast across Saturn's rings. Since Earth is much closer to the Sun than Saturn, only the day side of the planet is visible from the Earth. In fact, this image mosaic was taken in January 2007 by the robotic Cassini spacecraft now orbiting Saturn. The beautiful rings of Saturn are seen in full expanse, while cloud details are visible near the night-day terminator divide.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 15, 2012

-The thin waxing crescent Moon shines to the right of distant little Mars in evening twilight, as shown here.

Astro Picture of the Day:
November 15, 2012

Source:
This month's New Moon brought a total solar eclipse to parts of planet Earth on November 13 (UT). Most of the total eclipse track fell across the southern Pacific, but the Moon's dark umbral shadow began its journey in northern Australia on Wednesday morning, local time. But What does a solar eclipse look like from a plane? Above the clouds, it is very easy to see where the moon has covered the sun and where it has partially covered the sun. This neat solar eclipse photo was taken during a solar eclipse in 2010 and clearly demonostrates the dramatic darkening of the sky / ground as the shadow of the moon blankets the Earth. Under a total solar eclipse, the ground becomes almost night-like for a few minutes. Sunlight streaming through gaps in the rugged profile of the lunar limb creates the brilliant but fleeting Baily's Beads.

[massflavour]

Re: Terry's Astronomy Thread.

i've actually been able to see 3 auroras from within the city this year, and they were pretty good too.

great images in this thread.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 16, 2012

-Spot the crescent Moon in the west as twilight fades, and use it to guide your way down to little Mars, as shown here.

-The Leonid meteor shower, normally weak but occasionally surprising, should be at its best in the hours before dawn Saturday morning. Under a dark sky you may see about a dozen to 20 Leonids per hour. There is no Moon.

Astro Picture of the Day:
November 16, 2012

Source:
On the morning of November 14, the Moon's umbral shadow tracked across northern Australia before heading into the southern Pacific. Captured from a hilltop some 30 miles west of the outback town of Mount Carbine, Queensland, a series of exposures follows the progress of the total solar eclipse in this dramatic composite image. The sequence begins near the horizon. The Moon steadily encroaches on the on the reddened face of the Sun, rising as the eclipse progresses. At the total phase, lasting about 2 minutes for that location, an otherwise faint solar corona shimmers around the eclipsed disk. Recorded during totality, the background exposure shows a still sunlit sky near the horizon, just beyond a sky darkened by the shadow of the Moon.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 17, 2012

-With a small telescope, watch Jupiter's moon Ganymede slowly disappear into eclipse by Jupiter's shadow around 11:30 p.m. EST; 8:30 p.m. PST. Ganymede is just off Jupiter's western side.

-At roughly the same time, Jupiter's Great Red Spot (actually pale orange-tan) appears nearest to the center of the planet's disk.

Astro Picture of the Day:
November 17, 2012

Source:
This lovely view from northern Spain at Cape Creus on the easternmost point of the Iberian peninsula, looks out across the Mediteranean and up into the stream of the 2002 Leonid meteor shower. The picture is a composite of thirty separate one minute exposures taken through a fisheye lens. Over 70 leonid meteors are visible, some seen nearly head on. Bright Jupiter is positioned just to the right of the shower's radiant in Leo. Perched on the moonlit rocks at the bottom right, Leica, the photographers' dog, seems to be watching the on going celestial display and adds a surreal visual element to the scene. Sky watchers will have their best view under dark skies in early morning hours with Leo rising above the eastern horizon.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 18, 2012

-A low-altitude challenge: If the sky is very clear as twilight fades, aim your scope at tiny little Mars from a site with a low southwestern view. Follow Mars down as night falls. Can you detect the Lagoon Nebula, M8, and its embedded star cluster 1/3° or so to Mars's right?

-Algol in Perseus, the prototype eclipsing binary star, should be in one of its periodic dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 10:45 p.m. EST. Algol takes several additional hours to fade and to rebrighten.

Astro Picture of the Day:
November 18, 2012

Source:
How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, nearly making it the record holder. This star is the brightest object located just above the gas front in the above image. Close inspection of images taken with the Hubble Space Telescope, however, have shown that Pismis 24-1 derives its brilliant luminosity not from a single star but from three at least. Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the bottom of the image, stars are still forming in the associated emission nebula NGC 6357. Appearing perhaps like a Gothic cathedral, energetic stars near the center appear to be breaking out and illuminating a spectacular cocoon.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 19, 2012

-Fomalhaut, the "Autumn Star," culminates (reaches its highest point due south) around 7 p.m. now, depending on how far east or west you live in your time zone. High above, the western side of the Great Square of Pegasus points almost down to it. The other side of the Great Square points down roughly to Beta Ceti (Diphda or Deneb Kaitos), not quite so far.

Astro Picture of the Day:
November 19, 2012

Source:
What's happening in the sky over Monument Valley? A meteor shower. Over the past weekend the Leonid meteor shower has been peaking. The image - actually a composite of six exposures of about 30 seconds each - was taken in 2001, a year when there was a much more active Leonids shower. At that time, Earth was moving through a particularly dense swarm of sand-sized debris from Comet Tempel-Tuttle, so that meteor rates approached one visible streak per second. The meteors appear parallel because they all fall to Earth from the meteor shower radiant - a point on the sky towards the constellation of the Lion (Leo). Although the predicted peak of this year's Leonid meteor shower is over, another peak may be visible early tomorrow morning. By the way - how many meteors can you identify in the above image?

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 20, 2012

-First-quarter Moon (exact at 9:31 a.m.). The Moon shines high in the south in early evening, below the Water Jar of Aquarius.

-Saturn (magnitude +0.6, in Virgo) is lower left of bright Venus before and during dawn. They appear closer together every day. They're on their way to a conjunction less than 1° apart on the American mornings of November 26th and 27th.

Astro Picture of the Day:
November 20, 2012

Source:
Have you ever seen a halo around the Moon? This fairly common sight occurs when high thin clouds containing millions of tiny ice crystals cover much of the sky. Each ice crystal acts like a miniature lens. Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Moon Halo. A similar Sun Halo may be visible during the day. The setting of the above picture is Athens San Sebastian, Greece. The distant planet Jupiter appears by chance on the halo's left. Exactly how ice-crystals form in clouds remains under investigation.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 21, 2012

-Algol is at minimum light again, for a couple hours centered on 7:34 p.m. EST. Algol takes several additional hours to rebrighten.

-Venus (magnitude –3.9, in Virgo) rises in the east an hour before the first glimmer of dawn. By dawn it's shining brightly in the east-southeast, as shown above.

Look for much-fainter Saturn lower left of Venus, and Spica to Venus's right or upper right.

Astro Picture of the Day:
November 21, 2012

Source:
As the total phase of last week's solar eclipse came to an end, sunlight streaming past the edge of the Moon created the fleeting appearance of a glistening diamond ring in the sky. And while most eclipse watchers did not consider clouds a welcome sight, a view through thin clouds north of Cairns in Queensland, Australia also revealed these remarkable flickering shadow bands. Projected onto the cloud layer, the bands are parallel to the sliver of emerging sunlight. Caused by turbulence in Earth's atmosphere refracting the sliver of sunlight, the narrow bands were captured in this brief, 1/1000th second exposure.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 22, 2012

-The Moon is under the Great Square of Pegasus as the stars come out.

-Jupiter's moon Io disappears into eclipse by Jupiter's shadow, barely beyond the planet's western edge, at 11:20 p.m. EST (8:20 p.m. PST). Jupiter's Great Red Spot transits the planet's central meridian around 10:16 p.m. EST.

Astro Picture of the Day:
November 22, 2012

Source:
A cosmic grain of sand left the long and colorful trail across this all-sky view. Its grazing impact with planet Earth's atmosphere began at 71 kilometers per second. With the Milky Way stretching from horizon to horizon, the scene was captured on the night of November 17 from the astronomically popular high plateau at Champ du Feu in Alsace, France. Of course, the earthgrazer meteor belongs to this month's Leonid meteor shower, produced as our fair planet annually sweeps through dust from the tail of periodic Comet Tempel-Tuttle. The shower's radiant point in the constellation Leo is very close to the eastern horizon, near the start of the trail at the lower left. Bright planet Jupiter is also easy to spot, immersed in a faint band of Zodiacal light just below and right of center. The image is part of a dramatic time-lapse video that began only 7 minutes before the long leonid crossed the sky. Link to video is here: http://vimeo.com/53980967

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 23, 2012

-Some pre-telescopic astronomy: Sometime between 6:30 and 8:30 this evening, depending on how far east or west you live in your time zone, bright Vega sinking in the northwest and bright Capella climbing in the northeast (well left of brighter Jupiter) will be at exactly the same height. How accurately can you time this event for your location? An astrolabe would help.

-Altair is the brightest star in the west-southwest. (It's far lower left of brighter Vega.) Look above Altair, and perhaps a bit left, for the dim but distinctive little constellation Delphinus, the Dolphin.

Astro Picture of the Day:
November 23, 2012

Source:
East of Antares, dark markings sprawl through crowded star fields toward the center of our Milky Way Galaxy. Cataloged in the early 20th century by astronomer E. E. Barnard, the obscuring interstellar dust clouds include B59, B72, B77 and B78, seen in silhouette against the starry background. Here, their combined shape suggests a pipe stem and bowl, and so the dark nebula's popular name is the Pipe Nebula. The deep and expansive view was represents nearly 24 hours of exposure time recorded in very dark skies of the Chilean Atacama desert. It covers a full 10 by 10 degree field in the pronounceable constellation Ophiuchus. The Pipe Nebula is part of the Ophiuchus dark cloud complex located at a distance of about 450 light-years. Dense cores of gas and dust within the Pipe Nebula are collapsing to form stars.

[Bluearrowll]

Re: Terry's Astronomy Thread.

What's in the sky tonight?
November 24, 2012

-Look left of the Moon this evening, by a fist-width at arm's length or a little more, for the two or three brightest stars of Aries.

-Mercury emerges into dawn view around November 24th or so, brightening from magnitude +1 to 0 this week. Look for it just above the east-southeast horizon in early dawn, far to the lower left of Venus and Saturn as shown here. Mercury is beginning its best apparition of the year for viewers at mid-northern latitudes.

Astro Picture of the Day:
November 24, 2012

Source:
Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the chemical constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax galaxy cluster. This sharp color image shows intense star forming regions at the ends of the bar and along the spiral arms, and details of dust lanes cutting across the galaxy's bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365's prominent bar plays a crucial role in the galaxy's evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole. Discovered on October 27, the position of a bright supernova is indicated in NGC 1365. Cataloged as SN2012fr, the type Ia supernova is the explosion of a white dwarf star.