Feb 15, 2011

A Three-Planet Month

Jupiter, Saturn, and Venus are the only planets visible to the unaided eye in February.

As evening twilight
fades after February days, the sole bright planet visible is Jupiter, prominent
in the southwest. 
It sets a couple hours later, leaving the sky empty of any planets bright or
dim  for a little while. 
Then Saturn rises in the east, and it in turn is the only planet visible until
blazing Venus rises 2 or 3 hours before

Jupiter comes into view at dusk less than halfway up the southwest sky
(for observers around 40°north
latitude). It dims slightly in February, to magnitude 2.1, and its apparent
diameter dwindles a bit to 34.
Theres still much to check on its globe, however, including the status of 
the South Equatorial Belt and the 
Great Red Spot (SkyandTelescope.com/redspot). This is the last month 
until July when Jupiter will be high 
enough for good telescopic observations.

Jupiter crosses into the north celestial hemisphere on February 5th,
and late in the month it leaves Pisces 
for a brief journey through the northwest corner of Cetus. Jupiter sets 
around 9:30 p.m. as February opens
but around 8 pm as the month ends.

Uranus, faint at magnitude 6, had a close conjunction with Jupiter in
early January, but it begins February
almost 4° to Jupiters lower right. Jupiters swifter motion carries it to
6 from Uranus on February 14th 
and almost 8½°by months end.

Saturn rises in the east in Virgo around 10:30 p.m. on February 1st and
two hours earlier on February 
28th. The former is an hour after Jupiter sets, the latter only a half hour.
The ringed world brightens a l
ittle, from magnitude +0.7 at the beginning of February to +0.5 at month
Saturn was less than 8°from Spica in late January, but now the planet is
moving westward (retrograding) 
away from Spica.

The curved arrows indicate each planet’s movement during February, as if you were looking down on the solar system from the constellation Ophiuchus. The outer planets don’t change position enough in a month to notice at this scale.

Saturn culminates (is highest in the south) around 4:30 a.m. at the start of February and 2:30 a.m. at month’s end. The rings are getting a bit narrower during February, but they’re still close to 10° from

Venus rises while the sky is still fully dark throughout February, but the interval between Venus-rise and sunrise shrinks from 3 to 2 hours. Venus loses a bit of its tremendous luster this month, fading from magnitude –4.3 to –4.1. Its disk shrinks to less than 16″ in February, while its phase grows to  more  than 70% lit.
 Venus glides eastward across Sagittarius this month, passing several stars and deep-sky  objects.
 Pluto is also in Sagittarius, but it’s too faint to view when it’s so low in the sky. Interestingly, however, Pluto is only 2.3° north of Venus on February 9th. Pluto is usually far in the sky from the major planets, but it has been approaching the ecliptic in recent years and will cross it in 2018. So for the next decade, Pluto will have many encounters with
 Mercury, coming off a fine morning apparition in early January, rises only about 45 minutes before the  Sun on
February 1st (for viewers around 40° north). On that date, can you detect the planet with  binoculars just below the
crescent Moon very low in the southeast about 25 to 15 minutes before sunrise? Mercury is completely lost in the dawn
glow a few dawns later. It reaches superior conjunction with the Sun on February 25th.
Mars and Neptune also reach conjunction with the Sun this month, on February 4th and 17th,  espectively. So both
are unobservable.

The Moon is a very slender crescent a few degrees above Mercury at dawn on February 1st.  A waxing crescent Moon shines to the right of Jupiter on the evening of February 6th and above it on the 7th. The Moon is waning gibbous and rising in the late evening when it forms a triangle with Saturn and Spica on February 20th, and a vertical line with them on February 21st. The last-quarter Moon hangs to the left of Antares at dawn on February 25th. The waning lunar crescent is upper right of Venus at dawn on February 28th and lower left of Venus on March 1st.

Dec 31, 2010

Upcoming Solar Eclipse on January 4, 2011

Some of the world will be able to greet the first part of the new year with a solar eclipse. On the morning of Tuesday, January 4, 2011, an eclipse of the Sun will be widely visible across Europe and as far east as India. The eclipse won’t be visible in North and South America, however. Jay Pasachoff of Williams College in the US is the Chair of the International Astronomical Union’s Working Group on Eclipses, and says that even at a maximum, this eclipse will be only partial, with some of the Sun always visible. Because the Sun is too bright to look at safely, Pasachoff stresses that special solar filters or projection methods should always be used to protect the eyes.

Pasachoff will be in Tel Aviv to view the eclipse, and since partial eclipses are usually not very scientifically useful, he is looking forward to just enjoying the eclipse instead of scrambling to set up various scientific equipment.
“Partial eclipses are fun, and much more relaxing for a total-eclipse scientist like me, since the pressure on me is low and nothing happens too fast,” he told us. “Seeing a partial or other solar eclipse happen right on time, to the second, can be inspirational to students to study hard so that they, too, can understand the Universe.”
This will be Pasachoff’s 52nd solar eclipse.
Radio astronomers do find partial eclipses useful, as with a radio telescope, or in the ultraviolet or x-rays from spacecraft, scientists can use the timing of when solar active regions are covered and uncovered to study the structure of solar storms in better detail than is otherwise possible, Pasachoff said.
For this eclipse, people in Western Europe will find the Sun already eclipsed as the day begins, with the eclipse lasting about 80 minutes more. On January 4, the Moon will gradually cover the Sun, over a period of about 3 hours. At maximum, the eclipse will be at the horizon at sunrise in England, with 75% of the Sun’s diameter covered, and then gradually emerge over the next hour and 20 minutes. In Paris or Berlin, 80% of the Sun will be covered near sunrise. Farther east, the Sun will be a bit higher in the sky at maximum, 22° high with 67% covered in Athens. In Israel and Egypt, the Sun will be 33° high with over 55% coverage at maximum.
The most important thing, Pasachoff said, is to view an eclipse safely.
“Whenever the ordinary Sun is visible, even only part of it, you should not stare at it,” he said. “Special solar filters are available cheaply, or dense welders’ glass will do. Another method of seeing that the Sun is eclipsed is to punch a hole a few millimeters across in a piece of cardboard and hold it up to the Sun while you face away from the Sun and see the Sun’s image projected on the ground or onto another piece of cardboard. This method is called projection with a pinhole camera. It is rare that haze or clouds are sufficient to reduce the Sun’s intensity enough that one can see a partially covered Sun safely.”
2011 is unusual in that it has only four partial solar eclipses, for all of which the darkest part of the Moon’s shadow passes off the Earth’s surface. In 2012, an annular eclipse in which the Moon’s disk is a little too small to cover the entire Sun will pass from Japan over the Pacific to California and farther into the U.S. on May 20. On November 14, 2012, a total solar eclipse, in which it becomes dark as twilight, will start in northeastern Australia and cross a broad swath of the South Pacific.

The animation shown in the diagram to the right illustrates the motion of the shadow of the Moon at five minute intervals. This animation runs in a continuous loop.
This graphic, provided by Dr. Andrew Sinclair, shows the grey penumbral shadow where the eclipse will be seen as a partial one. The UT time is shown in the upper right-hand corner of the diagram.

The global visibility of this solar eclipse is shown in the diagram below.
Click to enlarge

Eclipses Of The New year 2011

by J. Kelly Beatty

After three consecutive years of enjoying time in the Moon's shadow, eclipse-chasers must go through withdrawal during 2011 because no total solar eclipses occur. However, the year kicks off with a deep partial solar eclipse that favors northern Europe, and a pair of total lunar eclipses come later on.

Few events in nature offer the drama and spectacle of a total solar eclipse, as demonstrated by this one seen over China on August 1, 2008.
S&T: Dennis di Cicco
A solar eclipse can only happen at new Moon, when the lunar disk passes directly between us and the Sun. Conversely, a lunar eclipse occurs during full Moon, when our satellite passes through Earth's shadow. These alignments don't occur at every new and full Moon because the lunar orbit is tipped about 5° to Earth's orbital plane — only occasionally do the Sun, Earth, and Moon line up exactly enough for an eclipse to occur. Three types of lunar eclipse are possible (total, partial, and penumbral) depending on how deep the full Moon plunges into or near the umbra, our planet's dark, central shadow. If it goes all the way in, we see a total lunar eclipse that's preceded and followed by partial phases. If the Moon skims part way into the umbra, only the partial phases occur. And if its disk passes just outside the umbra, it still encounters the weak penumbral shadow cast by Earth. (Oddly, four penumbral eclipses occurred last year.) Fortunately, no matter which type occurs, a lunar eclipse is observable anywhere on Earth where the Moon is above the horizon.
Because the Moon casts a smaller shadow than Earth does, eclipses of the Sun require observers to be in the right place at the right time. If the Moon completely hides the Sun, even for a moment, the eclipse is considered total. With its brilliant disk completely covered, the Sun's ghostly white outer atmosphere is momentarily revealed for anywhere from seconds to several minutes. However, this totality can only be viewed a narrow track or path on Earth's surface. Outside that path, about half the world is able to watch a partial eclipse as the Moon obscures a portion of the Sun.
Occasionally the Moon passes directly in front of the Sun but doesn't completely cover it. This odd-sounding situation is an annular eclipse, so-called because you can see a ring, or annulus, of sunlight surrounding the lunar disk. But an annular's path is likewise narrow, and outside of it observers see only a partial cover-up. No annular eclipses occur in 2011.
Interestingly, up to seven eclipses can take place in one year, and the last time that happened was 1982. The fewest possible is four, as was the case last year. Yet any given year can have only two "central" (annular or total ) solar eclipses, and again there was one of each in 2010.
Below are brief descriptions of this year's eclipses of the Sun and Moon.

January 4th's partial solar eclipse favors viewers in northern Europe, western Asia, and northern Africa. Blue lines show how much of the Sun's diameter is covered; green lines give Universal Time for mid-eclipse. Click on the image for a global view.
Fred Espenak
January 4: Partial Solar Eclipse
The year kicks off with a deep partial eclipse of the Sun that favors Europe (especially Scandinavia), northern Africa, and western Asia. Unfortunately, none of this event is visible from North America. Here's a sampling of cities offering good views, followed by the Universal Time of mid-eclipse at that location and how much of the Sun's disk is covered: Madrid (7:52, 47%), Paris (8:09, 65%), London (8:12, 67%), Stockholm (8:42, 79%), and Moscow (9:04, 75%). To see this eclipse at its maximum, you need to be in northeastern Sweden at 8:50:35 UT.
Skywatchers as far south as Nigeria and as far east as Mongolia have a chance to see the Moon's silhouette take at least a small bite out of the Sun.
June 1: Partial Solar Eclipse
A sequence of three syzygies over one month's time begins with a partial solar eclipse that falls across some of the world's least inhabited landmasses: Siberia, northern Canada, and Greenland. Mid-eclipse occurs at 21:17 UT. From the North Pole you'd see about one third of the Sun's disk covered by the Moon. Residents of Reykjavik, Iceland, can look forward to seeing 35% of the Sun's disk hidden near sunset. Alaskans north of Fairbanks and residents of northern New Brunswick and Nova Scotia have a chance to see slight divots in the Sun around midday and near sunset, respectively

The long-lasting total lunar eclipse on June 15, 2011, favors skywatchers in the Eastern Hemisphere.
Fred Espenak
June 15: Total Lunar Eclipse
Two weeks after a New Moon and a corresponding partial solar eclipse, the full Moon plunges deeply through Earth's umbra in the first of this year's total lunar eclipses. Totality lasts a whopping 100 minutes — nearly 40 minutes longer than the well-observed lunar eclipse in December 2010. The Moon is completely covered from 19:22 to 21:02 UT, and the partial phases begin one hour beforehand and end an hour afterward. To the chagrin of North American viewers, this timing places the June 15th event almost entirely over the Eastern Hemisphere, though viewers in eastern South America can see its later stages. July 1: Partial Solar Eclipse
The third event in this year's three-eclipse trifecta is a partial solar eclipse that few people, if any, can see. The path crosses the Antarctic Ocean well south of Africa, from which the Moon's indentation on the Sun's disk will be barely noticeable when mid-eclipse occurs at 8:38 UT.
November 25: Partial Solar Eclipse
Although the Moon takes a bigger bite of the Sun during November's event, the far-southern path is no better placed for viewing. Researchers at the South Pole can see about 75% of the Sun's diameter covered when the event peaks there at 6:30 UT. Slight partial phases can be seen from the southern tip of Africa just after sunrise and from Tasmania and southernmost New Zealand just before sunset.

Skywatchers in western North America have the best seats for the total lunar eclipse on December 10, 2011.
Sky & Telescope illustration
December 10: Total Lunar Eclipse
Year's end offers the finest spectacle of 2011 for skywatchers in the western U.S. and Canada: a total lunar eclipse before dawn. Totality extends from 6:06 to 6:57 a.m. PST (14:06 to 14:57 UT). The partial phase begins at 4:46 a.m. PST, when the Moon's leading edge enters the dark umbra of Earth's shadow, and the final bit of the Moon's disk exits the umbra at 8:18 a.m. But by then the Moon will have set (and the Sun risen) everywhere east and south of British Columbia. The entire eclipse is visible in the Pacific Ocean and much of Asia. Looking ahead to next year, 2012 will in some sense represent a reversal of fortunes from 2011. There'll be two central solar eclipses: an annular on May 20th (visible from the Pacific and western U.S.) and a total on November 13th (northeast Australia and South Pacific). But lunar eclipses will be limited to a partial event on June 28th and a barely-there penumbral eclipse on November 28th.

Dec 22, 2010

21st December 2010 Total Lunar Eclipse Photos

Space shuttle Discovery stands on Launch Pad 39A as the lunar eclipse takes place.

Stephen Edgar, Waterloo, Ontario

Dave Grass, southeastern Saskatchewan

Ramon Sasso, Santiago, Chile

The moon as seen from  Southern NH,  United States. Courtesy Marc Nozell 2008 Lunar Eclipse.
Matt D, New York City

Joseph Woodward, Grayslake, Illinois

Dec 16, 2010

Qatar Led Team Discovers Exoplanet

When listing the major scientific powers, the tiny nation of Qatar is not one that generally comes to mind. However, a Qatar astronomer, partnered with teams from the Harvard-Smithsonian Center for Astrophysics (CfA) as well as other institutions has just discovered a new exoplanet, dubbed Qatar-1b.
The planet itself, is another in the class of hot Jupiters which are massive, gassy planets that orbit their stars extremely closely. It has an orbital period of 1.4 days and is expected to be tidally locked with its parent star, a K type star.
It was discovered by a set of wide angle cameras located in New Mexico which are capable of surveying a large number of stars at a single time. The goal was to find planets that eclipsed the parent star and would thus show regular variations in their light curve. Images taken from this system were then sent to teams working at Universities in St. Andrews, Leicester, and Qatar. These teams processed the images and narrowed the stars down to a list of a few hundred candidates to be studied further.
From there Dr. Khalid Al Subai as well as the Harvard CfA team used the Smithsonian’s Whipple 48-inch telescope to more accurately measure the transits as well as as their 60-inch telescope to make spectroscopic observations to weed out binary star systems. These observations confirmed the existence of the planet.
“The discovery of Qatar-1b is a great achievement — one that further demonstrates Qatar’s commitment to becoming a leader in innovative science and research,” said Al Subai. Indeed, in the past 15 years, Qatar has undergone a large revolution towards science and education. Many universities have begun to open remote campuses, including Carnegie Mellon and Texas A&M.
“The discovery of Qatar-1b is a wonderful example of how science and modern communications can erase international borders and time zones. No one owns the stars. We can all be inspired by the discovery of distant worlds,” said CfA team member David Latham.

Landfall at Santa Maria for Opportunity on Mars

NASA’s Opportunity Mars rover arrived yesterday (Dec .15) at Santa Maria crater on Sol 2450. She sits just 20 meters from the crater rim. A multitude of inviting rocks and boulders are strewn about the 80 meter diameter crater, making this a Martian geologists dream.
And so it goes too for a Martian photographer with lots to shoot and with the giant 14 km wide Endeavour crater serving as backdrop and coming into ever clearer focus.
Santa Maria is just 6 km from the western rim of Endeavour (see panoramic mosaics above and below). 

Opportunity has been on a swift advance since departing from Intrepid crater in mid-November and driven about 1.5 km over very smooth terrain. The rover continues to benefit from a bounty of solar power and upgraded software enabling longer and more frequent days of drives. Opportunity has now driven a total of 26.4 km. 

Add caption    

The rover team is planning for an extensive and multi week science campaign at Santa Maria using all the instruments and cameras at their disposal.
Opportunity will spend the holiday season and the upcoming Solar conjunction exploring around Santa Maria according to Matt Golembek, Mars Exploration Program Landing Site Scientist at the Jet Propulsion Laboratory (JPL), Pasadena, Calif.
There will be no uplink commanding to the spacecraft around the actual conjunction period from Jan. 28 to Feb. 12 (UTC) out of caution that the command transmission could be disrupted.
The team plans a sophisticated wide-baseline stereo-imaging survey of Santa Maria by having Opportunity drive to several positions halfway around the crater. A mineral survey will be carried out using the spectrometers, microscope and drill – known as the RAT or rock abrasion tool – located at the terminus of the rover’s robotic arm. 

The rover is now at the two thirds mark of a 19 km (12 mile) journey from Victoria crater on the road to reach the rim of the scientifically rich environs of Endeavour crater sometime later in 2011. Opportunity explored the rim and interior of Victoria from mid-2006 to mid-2008.
Santa Maria is the largest feature that Opportunity will explore between Victoria and Endeavour craters. The team assigns informal names to craters visited by Opportunity based on the names of historic ships of exploration in human history. See Opportunity traverse maps below.
More than 95 percent of the data from Spirit and Opportunity are relayed by NASA’s Mars Odyssey orbiter. Today, Odyssey broke the record for being the longest-serving spacecraft at the Red Planet during it’s 3,340th day in Martian orbit.

Dec 11, 2010

Wininners of Astronomy’s 2010 photo contest

The results are in. Four individuals from four countries took home the prizes in Astronomy magazine’s 2010 Astroimaging Contest. Astronomy editors chose the winning images.

The overall winner is Thomas Bader of Rheinfelden, Germany. His image from Hao Island in French Polynesia of the eclipsed Sun taken during the July 11, 2010, total solar eclipse shows incredible detail, both in the Sun’s corona (outer atmosphere) and on the Moon’s surface, where features shining from light reflected off Earth are easily visible during totality. For his image, Bader wins a Celestron CPC 1100 GPS XLT 11-inch Schmidt-Cassegrain telescope.

he winner in the General category is Tunç Tezel of Bursa, Turkey. His image of the southern Milky Way from Mangaia, one of the Cook Islands in the South Pacific, shows the closest star system to Earth, Alpha Centauri, the Southern Cross, the Magellanic Clouds (two of our galaxy’s satellites), and thousands upon thousands of other stars. Tezel wins a DMK 21AU04.DS CCD camera courtesy of Imaging Source.

In the Deep-sky category, longtime Astronomy magazine contributor Ruben Kier of Orange, Connecticut, bested the competition. His superb image shows three galaxies — M65, M66, and NGC 3628 — collectively called the Leo Trio because of the constellation in which they reside. Kier wins a DMK 41AU02.AS CCD camera from Imaging Source.

Top honors in the Solar System category go to Li-Chun Chen of Taipei, Taiwan. He combined 32 exposures of the July 11, 2010, total solar eclipse from Hao Island in French Polynesia into one dramatic image that documents the event. Chen wins a DMK 31AU03.AS CCD camera contributed by Imaging Source.

Astronomy magazine Photo Editor Michael E. Bakich talked enthusiastically about the participation: “This year’s entries — 77 in all — went way beyond expectations. I received submissions from longtime contributors and also from many people who had never sent the magazine an image before.”

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