Comet 17P/Holmes Still Amazing Us

Now that a cold front has given central Florida back its nighttime sky, at least for a few evenings, this would be the perfect time to check out amazing Comet 17P/Holmes. In the early morning of October 24, Spanish amateur astronomer Juan Santana noticed that normally dim Comet 17P/Holmes had brightened considerably from observations made on previous nights. The sudden million-fold increase in brightness allowed the comet to become visible to the naked eye. The comet's coma, or outer cloud of gas and dust, is now physically much larger than the planet Jupiter.

It was just such an eruption of gas and dust that allowed the comet to be discovered in November of 1892 by English amateur astronomer Edwin Holmes. This is an excellent imaging target for off-the-shelf digital cameras and backyard telescopes.

The comet is still located just to the East (left) of the constellation Perseus. If you are in the Tampa Bay area, Perseus will rise in the North East and be completely above the horizon after 7PM EST. Comet 17P/Holmes should be visible roughly one-third of the way between Mirfak, the brightest star in Perseus, and the first magnitude wintertime star Capella, the brightest star in the constellation Auriga.

BACKGROUND: Comet 17P/Holmes was discovered by British amateur astronomer Edwin Holmes (1842-1919) on November 6, 1892 while conducting regular observations of the Andromeda Galaxy (M31). The orbital specifics for the comet are as follows: Aphelion distance, 5.2004 AU; Perihelion distance, 2.1655 AU; Semi-major axis, 3.618 AU ; Eccentricity, 0.4120; Orbital period, 7.0679 a (Julian years, lasting 362.25 days); Inclination, 19.1877°; Last perihelion, May 4, 2007; Next perihelion (predicted), March 27, 2014.

For more details and new information, check out these Web pages:

Space Weather Home Page:
http://spaceweather.com/

Space Weather Sky Chart:
http://spaceweather.com/images2007/24oct07/skymap_north_holmes.gif?PHPSESSID=ctmhv5tmpkfnk942ajcl3k17o7

Sky and Telescope Article:
http://www.skyandtelescope.com/observing/home/10862521.html


Phoenix Tilts Its Wings

On November 6, NASA's Phoenix Mars Lander mission team performed a spacecraft orientation adjustment to allow its solar panels to receive more energy from the sun.

During the first three months of the University of Arizona-led mission, which launched August 4, the spacecraft's solar panels were not pointed directly at the sun. If they had, the closer proximity to the sun would have overwhelmed the spacecraft's electrical systems.

With the spacecraft having covered 165 million miles of its 423 million mile journey to Mars, it receives less power as its distance from the sun increases.

The spacecraft also recently did a second trajectory correction maneuver that put it on course to be captured by the Martian gravitation field as it nears the planet. The spacecraft's original course was set from launch so that it would avoid hitting the planet if control problems arose. Additional trajectory corrections are scheduled for April and May to fine-tune the spacecraft's path to its landing site.

The lander is slated to arrive on Mars May 25. The Phoenix mission will look for evidence of water and the elements of life on Mars. It will analyze soil and ice samples scooped from the planet's northern arctic region.

The $420 million mission is led by University of Arizona, the first public institution to lead a mission to Mars. To learn more, visit the mission home page: http://phoenix.lpl.arizona.edu/


Five-Planet Star System Discovered

On November 06, NASA scientists announced the discovery of a record-setting fifth planet discovered orbiting a single star. The discovery suggests that multi-planet systems such as ours may not be unusual.

The star is the sunlike 55 Cancri, located 41 light-years away in the constellation Cancer. Researchers describe the new planet as a "mini-Saturn" of about 46 Earth masses. It is the fourth out from the star in a large gap between the third and fifth planets, placing it in the estimated habitable zone around the star where water might remain liquid.

The planet's size implies that it is a Jovian-like planet of hydrogen and helium gas, but the finding raises the possibility that earthlike moons might be orbiting the planet.

55 Cancri's system of five planets all seem to orbit along relatively circular paths, and the farthest planet out, a gaseous super-giant the size of four Jupiters, orbits at roughly the same distance from its star as the the distance of our Jupiter from the sun.

55 Cancri's innermost planet, weighing in at more than 10 earth masses—meaning it could have a rocky or icy core—lies closer to its star than Mercury does to our own. The new planet sits at 0.8 earth-sun distances (astronomical units) from the star, or roughly the distance between Venus and the sun. Before this discovery, researchers knew of only one other four-planet system, Mu Arae, and several three-planet systems.

55 Cancri system is one of many stars that for 18 years have been carefully and regularly measured by California's Lick Observatory and Hawaii's Keck Telescope. Researchers looked at the star's Doppler shift--the change in the wavelength, or color, of its light as it moved toward and away from Earth. A star tugged by an orbiting planet will wobble slightly, which can be detected as a regular shift in the star's color corresponding to the time the planet requires to complete an orbit. For example, 55 Cancri's outer planet has an orbital period of 14 years, and so was not discovered until 2004.

The research team's report has been accepted for future publication in The Astrophysical Journal. To learn more about the discovery and the observatories participating in the research, check these links:

University of California Observatories, Lick Observatory:
http://www.ucolick.org/

W. M. Keck Observatory:
http://www.keckobservatory.org/


Leonid Meteors Return

November 17 marks the peak of the annual Leonid meteor shower. Meteors from this shower may be visible from Nov. 15 through Nov. 20. Leonid meteors have an entry velocity of 71 km/second and glow with a bluish-green tint. This shower is caused by Periodic Comet 55P/Tempel-Tuttle, which returns to the inner solar system every 32.9 years. Meteor hourly rates are irregular and may reach 40 or greater in years surrounding the return of the comet. But since that last occurred in 1999, we can probably expect a rate of 10 to 15 per hour. The best chances to see Leonids are in the early morning hours during the days surrounding the peak (Nov. 16, 17, 18). The meteors will appear to originate from a point in the constellation of Leo (RA 10hrs 08min, Dec +22°).

The Leonids played a great role in our understanding of meteor showers. The great meteor storm of November 12-13, 1833 is regarded as the date of the birth of meteor astronomy. Following that meteor storm, Professors Olmsted and Twining of then Yale College pointed out that the meteors appeared to radiate from a point in the constellation Leo, the Lion. The fact that the meteors radiated from a single point indicated that they were all part of a swarm of meteoroids moving in the same orbital path. Later, Professor Hubert Anson Newton (1830-1896) an astronomer and mathematician who was also of Yale College, calculated that the orbit had a period of 33 years and used records to trace appearances of the shower as far back as AD 902. He also observed that the time of the Leonid shower moved along the calendar at the rate of about a month in a hundred years. Newton then successfully predicted the appearance of the 1866 Leonid storm. A few weeks after the 1866 storm astronomers found that the orbit of the meteoroid stream was identical with Temple's Comet, seen a year earlier. About this same time Italian astronomer Giovanni Schiaparelli (1835-1910) showed that the Perseid meteors came from a stream that moved in an orbit identical to the bright comet of 1862. These were the first observations to connect comets with the fall meteor showers.

There is historical evidence that Abraham Lincoln (1809-1865) also witnessed the great Leonid meteor storm of 1833 as a young man of 24. According to cross-referenced records and personal journals, Lincoln was apparently in New Salem, Illinois staying at the Rutledge Tavern, a log cabin then owned by Henry Onstot, a cooper by trade (bucket and barrel maker) and member of the Cumberland Presbyterian Church. Lincoln recounted the story in the presence of American writer Walt Whitman (1819-1892) who was a frequent guest of the Lincoln White House. Whitman later published the story in his book "Specimen Days & Collect," published in 1882. When asked by another White House guest whether the Union would survive the ongoing Civil War, Whitman noted that Lincoln, ever the story-teller, replied with this story. "When I was a young man in Illinois," said he, "I boarded for a time with a Deacon of the Presbyterian church. One night I was roused from my sleep by a rap at the door, & I heard the Deacon's voice exclaiming 'Arise, Abraham, the day of judgement has come!' I sprang from my bed & rushed to the window, and saw the stars falling in great showers! But looking back of them in the heavens I saw all the grand old constellations with which I was so well acquainted, fixed and true in their places. Gentlemen, the world did not come to an end then, nor will the Union now."


Thank Yous

Thanks to MARS member James Dagget who, following our report on quasars in early galaxies, shared his memories of working in the Quasar TV plant in Plantation, Florida the 1970s. James knows better than most about the inconsistent "quality" that went into those sets before the name went on.

Thanks to MARS member Craig MacDougal for sharing his backyard binocular observation of Comet 17P/Holmes during an all-too-brief break in the cloud cover last week. At that time the comet shone brighter than second magnitude and still continues to impress us now.


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MARS IS COMING, PART 2

As we prepare for the December 24 opposition, please enjoy this next installment on the Red Planet Mars.

Early Observations

Mars was a puzzle to ancient astronomers. They did not understand why it sometimes moved through the sky in the same direction as the sun and other celestial objects (direct, or prograde, motion), and sometimes moved in the opposite direction (retrograde motion). In 1609 the German mathematician and astronomer Johannes Kepler (1571-1630) used the excellent naked-eye observations of Danish astronomer Tycho Brahe (1546-1601) to deduce empirically the laws of motion for Mars and so pave the way for the modern gravitational theory of the solar system. Rather than having a circular orbit with uniform motion, as suggested by earlier Ptolemy-inspired theories, Kepler found that the orbit of Mars was an ellipse along which the planet moved with non-uniform but predictable motion--faster when closer to the sun, slower when farther away.

The earliest telescopic observations of Mars were made in 1610 by Italian astronomer Galileo Galilei (1564-1642) . This was also the first time that Mars was clearly seen not as a point of light, but as a disk. The Dutch scientist and mathematician Christiaan Huygens (1629-1695) is credited with the first accurate drawings of the planet's surface markings. In 1659 Huygens made a drawing that showed a major dark marking that is now known as Syrtis Major. About 1666, the Martian polar caps were first noted by the Italian-born French astronomer Gian Domenico Cassini (1625-1712).

Many key discoveries were made by visual observers. In 1659, Huygens discovered that Mars rotates and, in 1666, measured that rotation to be 24 hours 40 minutes--over today’s measurement by only 3 minutes. In the 1780s, German-born British astronomer William Herschel (1738-1822) first noted the very thin Martian atmosphere, and Herschel also measured the tilt of the planet's rotation axis and first discussed the Martian seasons. In 1877 the U.S. Naval Observatory's Asaph Hall (1829-1907) discovered that Mars has two natural satellites. Visual observers also documented many meteorological and seasonal changes that occur on Mars, such as various cloud types, the growing and shrinking of the polar caps, changes in the color and size of the dark areas, an annual "wave of darkening" in the markings that sweeps across the planet in time with the shrinking of the polar caps, and an occasional "blue haze" in the atmosphere. Most of these events were not explained until Mars was visited by spacecraft.

Visible Surface Features

Aside from the white polar caps, Earth-based telescopes show Mars generally to have a bright red-orange-colored surface that is covered by dark markings. Originally, the bright areas were called deserts, and most of the large dark areas were called maria (Latin, meaning "oceans" or "seas") because observers once thought the dark areas were covered by water.

The dark markings cover about one-third of the surface, mostly in a band around the planet between latitudes 10° and 40° South. They are irregularly distributed, and their overall pattern can change over many years. The northern hemisphere has only three major dark features. One is called Acidalia Planitia, another is called Syrtis Major, and the third is a dark collar around the northern pole. These were once thought to be shallow seas or areas of vegetation. We now know that Mars' dark areas form and change as the winds move surface material. Images from orbiting spacecraft reveal that the dark areas are actually collections of many dark streaks and splotches that are associated with craters, ridges, hills, and other geologic features that can block the local winds.

The bright areas, which cover about two-thirds of the surface, have subtle shadings, but these probably also are the result of the winds moving surface material. Beginning in 1877 with Italian astronomer Giovanni Schiaparelli (1835-1910) and into the early 20th century, maps of Mars showed many canals or channels—thin lines connecting the darker surface markings and thought by some at the time to be transportation for agricultural irrigation. However, these markings were not seen later in the images taken by flyby and orbiting spacecraft. The canals were apparently features that observers thought they saw while trying to push the resolution limits of their telescopes. Other features, such as the "wave of darkening" and the "blue haze" described by early telescopic observers, are now known to result from a combination of the viewing conditions and changes in the reflective properties of the surface.

For telescopic observers, the most dramatic regular changes on Mars occur at the poles. As fall begins in a particular hemisphere, clouds develop over that polar region, and the cap, made of frozen carbon dioxide, begins to grow. The smaller cap in the north can extend to 55° latitude, the larger cap in the south can extend to 50° latitude. In spring the caps recede. During northern summer the northern carbon dioxide cap disappears completely, leaving behind a small water-ice cap. And during the southern summer there is a small residual cap composed of carbon dioxide ice and water ice.

Early telescopic observers noted times when Martian surface features were temporarily hidden. They generally thought these were caused by white clouds or yellow clouds, and they interpreted the white clouds to be gas and the yellow clouds to be dust. Spacecraft images have since confirmed these interpretations were correct, and that hazes, clouds, and fogs regularly hide the surface.

Images from spacecraft in Mars orbit have found a variety of low-lying clouds and fogs, often in topographic depressions such as valleys or craters. They have also revealed high, thin clouds, particularly at the terminator--the dividing line between the daytime and nighttime portions of the planet's observable disk. Orographic clouds, which are produced when moist air is lifted over elevated terrain and cooled, form around prominent topographic features such as craters and volcanoes. Winter at the middle latitudes is characterized by westward-moving, spiral-shaped storm systems that are similar to those on Earth. Most of these clouds are composed of water ice--the white clouds that were seen by the early telescopic observers.

Dust storms are common on Mars. They can occur at any time but are most frequent in southern spring and summer, when Mars is passing closest to the sun and surface temperatures are at their highest. Most of the storms are regional in extent and last a few weeks. But every two or three years, the dust storms become global. At their peak, dust is carried so high in the atmosphere that only the summits of the tallest volcanoes--up to 21 km (13 miles) above the planet's mean radius--are visible. Although too small to be observed from Earth, the small sand tornados, called dust devils, have been seen by spacecraft in Mars orbit and by surface craft such as Mars Pathfinder and the Mars Exploration Rovers.

Next time: "The Martian Atmosphere"


Bibliography

Mars. (2007). In Encyclopædia Britannica. Retrieved October 26, 2007 , from Encyclopædia Britannica Online: http://www.britannica.com/eb/article-9110149

Mars (2007). In The Columbia Encyclopedia, Sixth Edition 2007. Copyright 2007 Columbia University Press. Retrieved October 26, 2007 from Encyclopedia.com
http://www.encyclopedia.com/doc/1E1-Mars-ast.html

Planets: Mars. In NASA Solar System Exploration, Last updated October 23, 2007. Retrieved October 26, 2007, from the NASA Solar System Exploration website, maintained by NASA's Jet Propulsion Laboratory:
http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mars


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THE SKY THIS WEEK

Nov 11 - Dwarf Planet Ceres is at opposition (7.2 Magnitude)

Nov 11 – the star Antares is 0.4° north of the moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.

Nov 12 – Jupiter is 5° north of the moon

Nov 12 - Dwarf Planet Ceres at its closest approach to Earth (1.832 AU)

Nov 14 – Asteroid Juno is in conjunction with the sun

Nov 15 - Mars is stationary. The body appears motionless in the sky due to the turning point between its direct and retrograde motion.

Nov 17, 5:33 P.M. EST - First Quarter Moon

Nov 17 - Neptune is 1.0° north of the moon, occultation. An occultation occurs when one object passes in front of a smaller one, temporarily obscuring all or part of the background object from view.

Nov 17 – the moon occults the planet Neptune

Nov 17 - Leonid Meteor Shower Peak


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THIS WEEK IN HISTORY

Nov 11, 1572 - Tycho Brahe's Discovery of a supernova, SN1572, 435th anniversary

Nov 11, 1875 - Vesto Slipher's birthday

Nov 11, 1966 - Gemini 12 launch (Jim Lovell and Buzz Aldrin)

Nov 12, 1891 - Seth Nicholson's birthday

Nov 12, 1924 - Audouin Dollfus' birthday

Nov 12, 1980 - Voyager 1, Saturn Flyby

Nov 13, 1831 - James Clerk Maxwell's birthday

Nov 14, 1969 - Apollo 12 Launch (Manned Moon Mission)

Nov 14, 1971 - Mariner 9, Mars Orbit Insertion

Nov 16, 2001 - Genesis, L1 Orbit Insertion

Nov 17, 1597 - Henry Gellibrand's 410th Birthday

Nov 17, 1966 – Leonid Meteor Storm


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MUSICAL DIVERSION

The song called "The Girl I Left Behind Me" has much folklore associated with it. Some say the song’s tune was popular as far back as the reign of Queen Elizabeth I, and that it was regularly played when regiments left town or when man-of-war ships set sail.

One source reports that the tune was known in America as early as 1650 and that it was a traditional fife tune, imported from England as "Brighten Camp." The tune became generally popular during the American Revolution. The tune was known in Ireland as "The Rambling Laborer" and "The Spailpin Fanach" and was first published in Dublin in 1791.

The tune is easy to play on the fife--a small flute. This song, along with “Yankee Doodle,” is often associated with the famous painting called “The Spirit of ’76.”

There are many settings for this tune. Below are two version of “The Girl I Left Behind Me.” The first comes from a collection called “Songs of the Seventh Calvary.” The origin of the other version is not certain. A third song based on this tune follows them.


The Girl I Left Behind Me
(from “Songs of the Seventh Calvary”)

The hours sad I left a maid
A lingering farewell taking
Whose sighs and tears my steps delayed
I thought her heart was breaking
In hurried words her name I blest
I breathed the vows that bind me
And to my heart in anguish pressed
The girl I left behind me

Then to the east we bore away
To win a name in story
And there where dawns the sun of day
There dawned our sun of glory
The place in my sight
When in the host assigned me
I shared the glory of that fight
Sweet girl I left behind me

Though many a name our banner bore
Of former deeds of daring
But they were of the day of yore
In which we had no sharing
But now our laurels freshly won
With the old one shall entwine me
Singing worthy of our size each son
Sweet girl I left behind me

The hope of final victory
Within my bosom burning
Is mingling with sweet thoughts of thee
And of my fond returning
But should I n'eer return again
Still with thy love i'll bind me
Dishonors breath shall never stain
The name I leave behind me

-----

The Girl I Left Behind Me
(an alternate version)

I'm lonesome since I crossed the hill,
And o'er the moorland sedgy
Such heavy thoughts my heart do fill,
Since parting with my Betsey
I seek for one as fair and gay,
But find none to remind me
How sweet the hours I passed away,
With the girl I left behind me.

O ne'er shall I foget the night,
the stars were bright above me
And gently lent their silv'ry light
when first she vowed to love me
But now I'm bound to Brighton camp
kind heaven then pray guide me
And send me safely back again,
to the girl I left behind me

Her golden hair in ringlets fair,
her eyes like diamonds shining
Her slender waist, her heavenly face,
that leaves my heart still pining
Ye gods above oh hear my prayer
to my beauteous fair to find me
And send me safely back again,
to the girl I left behind me

The bee shall honey taste no more,
the dove become a ranger
The falling waters cease to roar,
ere I shall seek to change her
The vows we made to heav'n above
shall ever cheer and bind me
In constancy to her I love,
the girl I left behind me.

-----


"Waxie's Dargle" is an old drinking song that is set to the same tune. Waxies were candlemakers, traditionally women, and "dargle" was a term for their annual working trip to Bray in Ireland. The River Dargle begins up in the Wicklow Mountains and finally empties into Irish Sea in Bray Harbor. Another source says the Dargle (a popular pub) was also a holiday haunt of the late eighteenth century Dublin candlemaker and grocer, Waxy O'Connor.

Here are some translations for the lyrics. “Auld one,” or old one, means wife. “Auld lad,” or old lad, means husband. In some versions the word “Uncle” is substituted with the phrase "Young Kill."


Waxie's Dargle

Says my auld one to your auld one
Will you come to the Waxie's dargle
Says your auld one to my auld one
Sure I haven't got a farthing
I've just been down to Monto town
To see Uncle McArdle
But he wouldn't lend me a half a crown
To go to the Waxie's dargle

Chorus:

What'll you have, will you have a pint
Yes, I'll have a pint with you, sir
And if one of us doesn't order soon
We'll be thrown out of the boozer

Says my auld one to your auld one
Will you come to the Galway races
Says your auld one to my auld one
With the price of my auld lad's braces
I went down to Capel Street
To the pawn shop money lenders
But they wouldn't give me a couple of bob
On my auld lad's red suspenders

(chorus)

Says my auld one to your auld one
We've got no beef nor mutton
But if we go down to Monto town
We might get a drink for nothin'
Here's a piece of good advice
I got from an auld fish-monger
When food is scarce and you see the hearse
You'll know you've died of hunger

(chorus)

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To review some the history, the text, or to listen to the melody, check out this pages from the "Songs of England" section of "Contemplations from the Marianas Trench - Music and Deep Thoughts"
- (The Girl I left Behind Me, Version 1) http://www.contemplator.com/england/girl.html
- (The Girl I left Behind Me, Version 2) http://www.contemplator.com/england/girl2.html
- (Waxie's Dargle) http://www.contemplator.com/england/waxie.html

To see a GIF image file of the score of the song, or to download an ABC file of the score, or other notations, visit this mirror site of Digital Tradition - http://sniff.numachi.com/pages/tiGIRLLFT1;ttBRGHTON.html

To see a GIF image file of the score of the song, or to download an ABC file of the score, visit this page of "The Session" - http://www.thesession.org/tunes/display/5418

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