Terry's Astronomy Thread.

[Bluearrowll]

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

-This is the time of year when the W shape of Cassiopeia is tipping nearly vertically in the northeast after dusk. It stands exactly vertically around 9 or 10 p.m., depending on your location. The W's brightest side is on top.

-New Moon (exact at 8:03 a.m. EDT).

-Mercury (magnitude –0.2) is deep in the sunset. Using binoculars, try scanning for it about 30 minutes after sundown very low in the west-southwest. Overall, this will be a poor apparition of Mercury. It stays lying low there for a month, then drops back into the Sun's glare.

Astro Picture of the Day:
October 15, 2012

Source:
Does this strange dark ball look somehow familiar? If so, that might be because it is our Sun. In the above image, a detailed solar view was captured originally in a very specific color of red light, then rendered in black and white, and then color inverted. Once complete, the resulting image was added to a starfield, then also color inverted. Visible in the above image of the Sun are long light filaments, dark active regions, prominences peaking around the edge, and a moving carpet of hot gas. The surface of our Sun has become a particularly busy place over the past two years because it is now nearing Solar Maximum, the time when its surface magnetic field is wound up the most. Besides an active Sun being so picturesque, the plasma expelled can also become picturesque when it impacts the Earth's magnetosphere and creates auroras.

[Bluearrowll]

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

-A twilight challenge: Use binoculars to look for Mercury and the hairline crescent Moon very low in the west-southwest shortly after sunset this evening, as shown here.

Astro Picture of the Day:
October 16, 2012

Source:
What's happening around that star? An unusual spiral structure has been discovered around the Milky Way star R Sculptoris, a red giant star located about 1,500 light years away toward the constellation of the Sculptor (Sculptoris). The star was observed with the new Atacama Large Millimeter/submillimeter Array (ALMA), the most powerful telescopic array observing near millimeter wavelengths, that part of the spectrum situated well beyond red light and between microwaves and radio waves. Data from ALMA observations was used to create a 3D visualization of the gas and dust immediately surrounding the star. A digital slice through this data showed the unexpected spiral structure. Although unusual, a similar spiral pattern was discovered in visible light recently around LL Pegasi in the second picture. Upon analyzing the data, a hypothesis was drawn that the red giant star in R Sculptoris might be puffing gas toward an unseen binary companion star. The dynamics of this system might be particularly insightful because it may be giving clues as to how giant stars evolve toward the end of their lives - and so release some constituent elements back to the interstellar medium so that new stars may form.

[Bluearrowll]

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

-Jupiter, Aldebaran, Beta Tauri, and the Hyades and Pleiades adorn the eastern sky this season, but that's not all. Below naked-eye visibility in the same area are the leading asteroids Vesta and Ceres, currently magnitudes 7.5 and 8.3, respectively. They're on their way to opposition in December.

-Completely invisible between them is NASA's Dawn spacecraft, which left Vesta earlier this year and will arrive at Ceres in February 2015.

Astro Picture of the Day:
October 17, 2012

Source:
Sometimes both heaven and Earth erupt. Colorful aurorae erupted unexpectedly earlier this month, with green aurora appearing near the horizon and brilliant bands of red aurora blooming high overhead. A bright Moon lit the foreground of this picturesque scene, while familiar stars could be seen far in the distance. With planning, the careful astrophotographer shot this image mosaic in the field of White Dome Geyser in Yellowstone National Park in the western USA. Sure enough, just after midnight, White Dome erupted - spraying a stream of water and vapor many meters into the air. Geyser water is heated to steam by scalding magma several kilometers below, and rises through rock cracks to the surface. About half of all known geysers occur in Yellowstone National Park. Although the geomagnetic storm that created these aurorae has since subsided, eruptions of White Dome Geyser continue about every 30 minutes.

[Bluearrowll]

Was unable to access site this morning - this one's a little late.


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

-The waxing crescent Moon poses over Mars and Antares low in the southwest in twilight, as shown below.

-Venus (magnitude –4.0, in Leo) rises in darkness around 4 or 5 a.m. daylight saving time (depending on where you live), coming above the eastern horizon more than an hour before the first glimmer of dawn. By dawn it's shining brightly in the east. Look increasingly far above it for Regulus this week.

Astro Picture of the Day:
October 18, 2012

Source:
Normally faint and elusive, the Jellyfish Nebula is caught in this alluring, false-color, telescopic view. Flanked by two bright stars, Mu and Eta Geminorum, at the foot of a celestial twin, the Jellyfish Nebula is the brighter arcing ridge of emission with dangling tentacles below and right of center. In fact, the cosmic jellyfish is seen to be 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. Emission nebula Sharpless 249 fills the field at the upper left. The Jellyfish Nebula is about 5,000 light-years away. At that distance, this image would be about 300 light-years across. The color scheme used in the narrowband composite was made popular in Hubble Space Telescope images, mapping emission from oxygen, hydrogen, and sulfur atoms to blue, green and red colors.

[gold stinger]

much props for keeping this thread going. There must be more information in this thread than NASA keeps on their website.

[Bluearrowll]

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

-The crescent Moon shines in the southwest as twilight fades. If it were a bow, it would be shooting an arrow to the lower right above the Mars-and-Antares pair, as shown here. Binoculars will help you pick out the two similar-looking, orange-red points.

-The annual Orionid meteor shower should be getting under way in the hours before dawn Saturday morning, and it should continue in the early-morning hours for the next few days. You may see 10 or 20 Orionids per hour. The shower's radiant point is at the top of Orion's Club, which doesn't rise high until after well midnight. There will be no moonlight for the next few mornings.

-At 10:48 p.m. Eastern Daylight Time, Jupiter's moon Io reappears out from behind Jupiter's eastern limb. Later, Jupiter's Great Red Spot crosses the planet's central meridian around 1:18 a.m. Saturday morning EDT (10:18 p.m. Friday evening PDT).

Astro Picture of the Day:
October 19, 2012

Source:
NGC 2623 is really two galaxies that are becoming one. Seen to be in the final stages of a titanic galaxy merger, the pair lies some 300 million light-years distant toward the constellation Cancer. The violent encounter between two galaxies that may have been similar to the Milky Way has produced widespread star formation near a luminous core and along eye-catching tidal tails. Filled with dust, gas, and young blue star clusters, the opposing tidal tails extend well over 50,000 light-years from the merged nucleus. Likely triggered by the merger, accretion by a supermassive black hole drives activity within the nuclear region. The star formation and its active galactic nucleus make NGC 2623 bright across the spectrum. This sharp cosmic snapshot of NGC 2623 (aka Arp 243) is based on Hubble Legacy Archive image data that also reveals even more distant background galaxies scattered through the field of view.

[Bluearrowll]

Over 8,000 visitors (35.75 visitors / day)! Love the surge in activity over the past month. I am still working out the front page, where to split the text. It's become too large to edit so I'm going to dump older posts starting at a certain point into my 2nd post in my thread. This will also allow me to improve some tracking features and add new ones down the road.

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

-As twilight fades this evening, Mars and Antares are at their minimum separation of 3½°. Look for them quite low in the southwest, as shown above.

-The annual Orionid meteor shower continues into the early morning hours tonight, and it should continue in the early morning hours for the next few days. You may see 10 or 20 Orionids per hour. The shower's radiant point is at the top of Orion's Club, which doesn't rise high until after well midnight. There will be no moonlight for the next few mornings.

Astro Picture of the Day:
October 20, 2012

Source:
Ghostly apparitions of two fundamental planes in planet Earth's sky span this October all-sky view. The scene was captured from a lakeside campsite under dark skies in northern Maine, USA. In it, the plane of our Milky Way Galaxy arcs above faint airglow along the horizon. Zodiacal light, a band of dust scattering sunlight along the solar system's ecliptic plane, stretches almost horizontally across the wide field and intersects the Milky way near a point marked by bright planet Jupiter. Right of Jupiter, past the Pleiades star cluster, is the brightening of the Zodiacal band known as the Gegenschein, also visible to the eye on that dark night. Rising above the distant mountains, Orion the hunter is reflected in the lake's calm waters.

[Bluearrowll]

I'm a little early today, but I'm off to climb the CN Tower in 20 minutes.

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

-First-quarter Moon (exact at 11:32 p.m. EDT). The Moon shines in the south to southwest during evening. Look for Altair high above it as the stars come out. Later in the evening, Altair is upper right of the Moon.

-The Orionid meteor shower continues into the early morning hours tonight, but the peak has since past and all that will be seen now are stragglers. You may see about 5-10 Orionids per hour. The shower's radiant point is at the top of Orion's Club, which doesn't rise high until after well midnight. The moon will still have set by the time the Orionids appear.

Astro Picture of the Day:
October 21, 2012

Source:
One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming. Light takes about 1,500 years to reach us from the Horsehead Nebula. The above image was taken with the 0.9-meter telescope at Kitt Peak National Observatory.

[Bluearrowll]

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

-Vega is the brightest star high in the west these evenings. Even higher above it is Deneb. Farther off to Vega's left or lower left is the third Summer Triangle star, Altair.

-Mercury (magnitude –0.2) is having a poor evening apparition. Using binoculars, look for it 20 or 30 minutes after sundown very low in the southwest, to the lower right of Mars and Antares.

Astro Picture of the Day:
October 22, 2012

Source:
The sky toward the center of our Galaxy is filled with a wide variety of celestial wonders, many of which are visible from a dark location with common binoculars. Constellations near the Galactic Center include Sagittarius, Libra, Scorpius, Scutum, and Ophiuchus. Nebulas include Messier objects M8, M16, M20, as well as the Pipe and Cat's Paw nebulas. Visible open star clusters include M6, M7, M21, M23, M24, and M25, while globular star cluster M22 is also visible. A hole in the dust toward the Galactic Center reveals a bright region filled with distant stars known as Baade's Window, which is visible between M7 and M8. Moving your cursor over the above image the will bring up an un-annotated version.

[Bluearrowll]

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

-Wintry Orion sparkles above the east-southeast horizon as early as 11 p.m. now, depending on your location. Earlier in the evening, keep watch for Orion rising below or lower right of brilliant Jupiter.

Astro Picture of the Day:
October 23, 2012

Source:
Normal cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. As water droplets grow, an opaque cloud forms. Under some conditions, however, cloud pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such pockets may occur in turbulent air near a thunderstorm. Resulting mammatus clouds can appear especially dramatic if sunlit from the side. These mammatus clouds were photographed over Regina, Saskatchewan, Canada during the past summer.

[Bluearrowll]

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

-Around 8 or 9 p.m. the Big Dipper lies low and level above the north-northwest horizon. The farther north you live, the higher it will appear. If you're as far south as Miami, it's below the horizon completely.

-Mars (magnitude +1.2, in Ophiuchus) is still low in the southwest in evening twilight. It's more or less above similar-looking Antares. The two are about 4° or 5° apart.

Astro Picture of the Day:
October 24, 2012

Source:
The large stellar association cataloged as NGC 206 is nestled within the dusty arms of neighboring spiral galaxy Andromeda (M31), 2.5 million light-years distant. Seen near the center of this gorgeous close-up of the southwestern extent of Andromeda's disk, the bright, blue stars of NGC 206 indicate its youth. Its youngest massive stars are less than 10 million years old. Much larger than the clusters of young stars in the disk of our Milky Way galaxy known as open or galactic clusters, NGC 206 spans about 4,000 light-years. That's comparable in size to the giant stellar nurseries NGC 604 in nearby spiral M33 and the Tarantula Nebula, in the Large Magellanic Cloud.

[Bluearrowll]

What's in the sky tonight?
October 25, 2012

-The W pattern of Cassiopeia is tipping nearly vertically high in the northeast after dusk. It stands exactly vertical around 9 p.m., depending on your location. The W's brightest side is on top.

-Jupiter (magnitude –2.7, in Taurus) rises in the east-northeast around 8 or 9 p.m. daylight saving time. Once it's clear of the horizon, look for fainter orange Aldebaran to its right and Beta Tauri (Elnath) a little farther to its left. By dawn this lineup-of-three stands high and vertical in the west.

Astro Picture of the Day:
October 25, 2012

Source:
Braided, serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun, as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star is near the center of the overall bright crescent shape. In this deep telescopic view, fainter filaments clearly extend below and to the left of the bright crescent region. The Medusa Nebula is estimated to be over 4 light-years across.

[Bluearrowll]

What's in the sky tonight?
October 26, 2012

-The Ghost of Summer Suns. Halloween is approaching, and this means that Arcturus, the star sparkling low in the west-northwest in twilight, is taking on its role as "the Ghost of Summer Suns." What does this mean? For several days centered on October 29th every year, Arcturus occupies a special place above your local landscape. It closely marks the spot in your sky where the Sun stood at the same time, by the clock, during warm June and July — in broad daylight, of course. So, in the last days of October each year, you can think of Arcturus as the chilly Halloween ghost of the departed summer Sun.

-The waxing gibbous Moon shines in the east early this evening. Look to its upper left for the Great Square of Pegasus, tipped onto one corner.

Astro Picture of the Day:
October 26, 2012

Source:
Every book has a first page and every catalog a first entry. And so this lovely blue cosmic cloud begins the van den Bergh Catalog (vdB) of stars surrounded by reflection nebulae. Interstellar dust clouds reflecting the light of the nearby stars, the nebulae usually appear blue because scattering by the dust grains is more effective at shorter (bluer) wavelengths. The same type of scattering gives planet Earth its blue daytime skies. Van den Bergh's 1966 list contains a total of 158 entries more easily visible from the northern hemisphere, including bright Pleiades cluster stars and other popular targets for astroimagers. Less than 5 light-years across, VdB1 lies about 1,600 light-years distant in the constellation Cassiopeia. Also on this scene, two intriguing nebulae at the right show loops and outflow features associated with the energetic process of star formation. Within are extremely young variable stars V633 Cas (top) and V376 Cas.

[Bluearrowll]

I am pleased to announce main page maintenance is complete and the main post is usable again - keep an eye out in the near future for upgrades! Main post has been reduced from about 356,000 characters to 105,000 characters due to archiving older entries in a different post.


What's in the sky tonight?
October 27, 2012

-The bright Moon shines below the Great Square of Pegasus's bottom corner early this evening. From the Square's left corner extends a big, slightly downward line of three stars (including the corner). These form the backbone and leg of Andromeda. Dark areas can also see the Andomeda Galaxy's glow here.

Astro Picture of the Day:
October 27, 2012

Source:
Supernova remnant Cassiopeia A (Cas A) is a comfortable 11,000 light-years away. Light from the Cas A supernova, the death explosion of a massive star, first reached Earth just 330 years ago. The expanding debris cloud spans about 15 light-years in this composite X-ray/optical image, while the bright source near the center is a neutron star (inset illustration) the incredibly dense, collapsed remains of the stellar core. Still hot enough to emit X-rays, Cas A's neutron star is cooling. In fact, 10 years of observations with the orbiting Chandra X-ray observatory find that the neutron star is cooling rapidly, so rapidly that researchers suspect a large part of the neutron star's core is forming a frictionless neutron superfluid. The Chandra results represent the first observational evidence for this bizarre state of neutron matter. More can be read about superfluids at The Chandra's site or Science Daily.

[Bluearrowll]

What's in the sky tonight?
October 28, 2012

-Plucked from obscurity to make astronomical history, the star 51 Pegasi will be known for all ages as the first Sun-like star discovered to host a planet beyond our solar system (in 1995). At 5th magnitude it's an easy binocular target next to the Great Square of Pegasus, even in moonlight. Can you spot it?

Astro Picture of the Day:
October 28, 2012

Source:
This colorful cosmic portrait features glowing gas and obscuring dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia. The nebula's colors were created by adopting the Hubble false-color palette for mapping narrow emission from oxygen, hydrogen, and sulfur atoms to blue, green and red colors, and further blending the data with images of the region recorded through broadband filters. Not far on the sky from the famous Double Star Cluster in Perseus, IC 1795 is itself located next to IC 1805, the Heart Nebula, as part of a complex of star forming regions that lie at the edge of a large molecular cloud. Located just over 6,000 light-years away, the larger star forming complex sprawls along the Perseus spiral arm of our Milky Way Galaxy. At that distance, this picture would span about 70 light-years across IC 1795.

[Bluearrowll]

What's in the sky tonight?
October 29, 2012

-Full Moon (exact at 3:49 p.m. Eastern Daylight Time). Look a fist-width above the Moon for the brightest stars of Aries, lined up nearly horizontally.

-Algol should be at minimum light for a couple hours centered on 10:03 p.m. EDT.

-Jupiter's Great Red Spot (pale orange-tan) crosses Jupiter's central meridian around 11:32 p.m. Eastern Daylight Time.

Astro Picture of the Day:
October 29, 2012

Source:
Oh what a tangled web a planetary nebula can weave. The Red Spider Planetary Nebula shows the complex structure that can result when a normal star ejects its outer gases and becomes a white dwarf star. Officially tagged NGC 6537, this two-lobed symmetric planetary nebula houses one of the hottest white dwarfs ever observed, probably as part of a binary star system. Internal winds emanating from the central stars, visible in the center, have been measured in excess of 1000 kilometers per second. These winds expand the nebula, flow along the nebula's walls, and cause waves of hot gas and dust to collide. Atoms caught in these colliding shocks radiate light shown in the above representative-color picture by the Hubble Space Telescope. The Red Spider Nebula lies toward the constellation of the Archer (Sagittarius). It's distance is not well known but has been estimated by some to be about 4,000 light-years.

[Bluearrowll]

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

-The "Summer Star" Vega is still the brightest star in the west during fall evenings. Higher above it is Deneb. Farther off to Vega's left or lower left is Altair, the third star of the Summer Triangle.

-Mars (magnitude +1.2, in Ophiuchus) remains low in the southwest in evening twilight. It's upper left of similar-looking Antares; they widen from 6° to 10° apart this week.

Astro Picture of the Day:
October 30, 2012

Source:
Lake Tekapo on South Island in New Zealand is arguably one of best night sky locations in the Southern Hemisphere. The significance of its pristine night sky without light pollution is recognised world-wide and is being included in the list of UNESCO Starlight Reserves. This shot centres around the setting milky way, upside down to how most northern are used to seeing it; this how the milky way looks like when deep in the southern hemisphere. Lake Tekapo has water so clear that most of the stars and the milky way would be visible in the mirror-like reflection of the waters.

[Bluearrowll]

What's in the sky tonight?
October 31, 2012

-The Halloween Moon, waning gibbous, rises around the end of twilight. The Pleiades are above it. Once it rises higher, Aldebaran sparkles is below it and bright Jupiter shines to its lower left, as shown here.
Just after dark, the faint, slow-moving asteroid 35 Leukothea should occult a 10.6-magnitude star in Aquarius fairly high in the south for up to 39 seconds, for observers along a track from Florida through Michigan.

Astro Picture of the Day:
October 31, 2012

Source:
Described as a "dusty curtain" or "ghostly apparition", mysterious reflection nebula VdB 152 really is very faint. Far from your neighborhood on this Halloween Night, the cosmic phantom is nearly 1,400 light-years away. Also catalogued as Ced 201, it lies along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of interstellar dust in the region block light from background stars or scatter light from the embedded bright star giving parts of the nebula a characteristic blue color. Ultraviolet light from the star is also thought to cause a dim reddish luminescence in the nebular dust. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud's velocity. This deep telescopic image of the region spans about 7 light-years.

[Bluearrowll]

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

-The bright "star" above the Moon this evening is Jupiter. Although they look close together, Jupiter is 1,500 times farther away. Aldebaran, to their right, is 930,000 times more distant than Jupiter!

-Jupiter (magnitude –2.7, in Taurus) rises in the east-northeast shortly after dark, with Aldebaran to its right. Above Aldebaran are the Pleiades.

Astro Picture of the Day:
November 1, 2012

Source:
The suggestively shaped Witch Head Nebula is a reflection nebula and is associated with the bright star Rigel in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula spans about 50 light-years and is composed of interstellar dust grains reflecting Rigel's starlight. In this cosmic portrait, the blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's intense blue starlight but because the dust grains scatter blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away.

[Bluearrowll]

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

-Once the waning gibbous Moon rises high late this evening, look lower right of it for wintry Orion making his sparkly appearance.

-The Great Red Spot's side of Jupiter is busy indeed. On October 29th when Christopher Go shot this below image from the Philippines, bright orange Oval BA and the little dark red dot following it had finished passing south of (below) the Great Red Spot. Huge turbulence roils the South Equatorial Belt behind the Great Red Spot, and in the midst of this, notice the tiny dark marking next to a bright little white outbreak.

-The South Temperate Belt is barely visible along some of its length but prominent elsewhere. Four white ovals dot the South South Temperate Belt. On the north (lower) side of the planet, the North Equatorial and North Temperate belts have become cleanly separated by the North Tropical Zone's return to whiteness. An extremely wide blue festoon intrudes into the bright Equatorial Zone north of the Great Red Spot.

Astro Picture of the Day:
November 2, 2012

Source:
At the center of our Milky Way Galaxy, a mere 27,000 light-years away, lies a black hole with 4 million times the mass of the Sun. Fondly known as Sagittarius A* (pronounced A-star), the Milky Way's black hole is fortunately mild-mannered compared to the central black holes in distant active galaxies, much more calmly consuming material around it. From time to time it does flare-up, though. A recent outburst lasting several hours is captured in this series of premier X-ray images from the orbiting Nuclear Spectroscopic Telescope Array (NuSTAR). Launched last June 13, NuSTAR is the first to provide focused views of the area surrounding Sgr A* at X-ray energies higher than those accessible to Chandra and XMM observatories. Spanning two days of NuSTAR observations, the recent flare sequence is illustrated in the panels at the far right. X-rays are generated in material heated to over 100 million degrees Celsius, accelerated to nearly the speed of light as it falls into the Miky Way's central black hole. The main inset X-ray image spans about 100 light-years. In it, the bright white region represents the hottest material closest to the black hole, while the pinkish cloud likely belongs to a nearby supernova remnant.