WADHURST ASTRONOMICAL SOCIETY
APRIL NEWSLETTER 2006
INDEX: MEETINGS, OTHER NEWS, CONTACTS
Members of the Committee are reminded that there will be a meeting of
the Wadhurst Astronomical Society Committee at 2000 on Monday 10th April 2006
at the Abergavenny Arms in Frant.
Any member of the Society is always welcome to come along to the
committee meetings and join us over a pint.
given by Martin Frey at the Society meeting on Wednesday 15th March 2006
This evening's talk was given by Martin Frey from the Homewood and District
Astronomical Society near Appledore. He
said they usually meet in a convenient pub.
As we were to see, there have been very many blunders made in the history
of Astronomy and as an introduction Martin began his talk by referring to a
number of blunders made during the discovery of the planet Neptune - and also
some lucky coincidences.
In 1781 John Herschel had discovered Uranus, the seventh planet from the
Sun, and in 1841 a young and brilliant mathematician undergraduate at Cambridge
University, detected irregularities in the movement of Uranus.
This mathematician was John Couch Adams from Cornwall and he calculated
the accurate position of a yet undiscovered planet that could possibly be
causing these perturbations. He
showed his results to the Director of Cambridge Observatory, professor James
Challis who was impressed and gave Adams a letter of introduction to take to
George Airy, the Astronomer Royal at Greenwich.
Martin regarded this as the first blunder to be covered in his talk
because Adams had an awkward and shy personality.
He wasn't able to see Airy who was having his dinner at three in the
afternoon, something Adams regarded as a put-down, but left his notes and
Airy then wrote to Adams asking if he had made allowance for the Radius
Vector of Saturn. Another blunder was the fact that Adams thought this too
trivial a question and never replied. A
further blunder was caused by the fact that neither Challis nor Airy
communicated Adams' notes to anyone and finally Neptune was discovered by a
German astronomer using calculations made by a French mathematician called Le
Verrier. These were the same as
calculations made earlier by Adams. Yet instead of feeling cheated, Adams
congratulated Le Verrier and they became friends.
Because of this friendship, both Adams and Le Verrier together attended a
conference in Washington, USA, in 1884 to decide the internationally agreed
Prime Meridian where with Adam's persuasion, Airy's transit line at Greenwich
became recognised as the World's standard.
Returning to the discovery of Neptune, Martin pointed out that a year
earlier or a year later and the relative positions of the two planets would have
been further apart and the perturbations would have been far smaller and would
not have resulted in the discovery of Neptune at that time.
Another fact was that Adams had been given a patch of sky 30 degrees by
ten degrees to search for this possible planet. He saw it right at the centre but unfortunately didn't
Now Martin took us back to Thales, credited as the first scientist, who,
in 585 BC was able to predict a solar eclipse; his blunder was to fall into a
ditch whilst looking up at the night sky but was recompensed by being retrieved
by a pretty young girl.
Thales was greatly respected by Aristotle who was born in 384 BC, but
Aristotle's blunder was his belief that the Earth was the centre of a perfect
Universe and the other planets and the Sun orbited around it.
Aristarchus, born in 310 BC, came to the rescue by realising that in fact
the Sun was the centre of our solar system and the Earth was in orbit around it.
By measuring the angle between the Moon and the Sun when the moon was
exactly half lit and creating a right angle, he estimated that the Sun was about
22 times the distance from the Earth to the Moon, but his blunder was to believe
that this distance was far to great and fiddled his measurements to make the Sun
closer to the Earth.
Eratosthenes, born in 276 BC, calculated that on the 21st June, the Sun
shone directly down onto Alexandria. Due
south was a deep well at Aswan where the light from the Sun reached the deepest
part only on June the 21st. The
distance between Aswan and Alexadria had been measured exactly by Pharaoh's
Pacers (disciplined walkers with precise strides).
From these distances and angles Eratosthenes calculated that the
circumference of the Earth was between 39,000 and 46,000 km.
(Now known to be 40,075 km)
In 391 AD came a huge blunder when nearly all the books in the great
Library at Alexandria were burnt, destroying most of the works by the ancient
Next, in about 1500 came Copernicus in Martin's list of astronomical
blunders when the Catholic Church rejected his theories about the Earth and its
orbit around the Sun and our position in the Cosmos.
Copernicus was followed by Galileo who confirmed the former's work but
was again persecuted by the Roman Catholic Church and arrested only to be
pardoned by Pope, Pope John as recently as 1999.
Suspicion of science even caused Newton to feel he had to carry out some
of his experiments in secret and behind curtains in the dead of night and also
Darwin's publications were thoroughly questioned.
Martin Frey concluded his talk by answering several questions from
members; one asking about the suggested existence of a planet orbiting at the
same rate as the Earth on the far side of the Sun locked in orbit at the third
Lagrange point. This turned out to be a blunder since space exploration has
found this point not to harbour an unknown planet.
19th April 2006. Our own Ian King tells us about "Instrumentation".
Members remembering Ian's last talk about imaging will know of his use of
instruments and the knowledge that goes with it.
Wednesday 17th May 2006. Dr. Robert
Smith gives a talk with the alarming title of "Things that go Bang in the
Wednesday 21st June 2006. We
are to have a Members evening, and are calling it "Summer Solstice
Telescope Evening" when members are invited to bring their telescopes along
and any other astronomical equipment. We
also get the chance to discuss our interests and problems with others. If any member would be interested in giving a short talk at
this meeting they would be very welcome indeed and should contact Phil Berry,
Ian Reeves or myself, Geoff Rathbone. The
subject does not have to be on pure astronomy, but experiences and visits to
locations can be just as interesting.
19th July 2006. Gilbert
Satterthwaite FRAS will be talking to us about "Sir George Airy's
Contribution to Positional Astronomy".
will be no August meeting but Michael Harte is again kindly offering to hold a
barbecue on Saturday 26th August 2006. Last
year we had an excellent evening with three or four telescopes and binoculars
and great hosts, but it would be good to see more members this year. Details to follow.
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monthly Newsletter is sent to all members of the Society with the intention of
informing members of activities, meetings and some of the latest news on
astronomical events. All paid up
members are entitled to receive it and we also send it out for three months
after subscriptions become due, to non-payers.
If they wish to continue to receive it after that, please let Michael
Wyles our treasurer know.
Now the spring has arrived it doesn't get dark until about 2100 BST.
Orion has virtually disappeared although Mars is still there but now has
a magnitude of only 1.4. Jupiter, magnitude -2.5, rises just before the Sun, as does
Venus at -4. Saturn at -0.1 is still well placed to the south just after dusk.
At present, Saturn is close to Leo whose head looks like a reversed
question mark with Regulus as the dot underneath.
Regulus has a magnitude of 1.36 and is a fairly hot star, 78 light years
When looking at the night sky I tend to think of the stars as a static
background. Not a bit of it.
Quasars are so distant that they are used as almost static reference
points against which the rest of the sky can be measured.
Barnard's Star is known to have the greatest proper motion with 10.7
seconds of arc per year. Not very
far from Regulus, at RA 11h 52' 42" Dec +37o 48' is "Groombridge
1830" moving at 7 arc seconds per year.
It is the third fastest moving star, and is 30 light years away with an
apparent magnitude 6.4. Its proper
motion means that it will have moved the equivalent of the diameter of the Moon
in just 250 years from now. Regulus
at 78 light years will take 7,000 years to travel that far, but in the opposite
Curiously, in 100,000 years the "W" in Cassiopeia will actually
resemble a reversed question mark just as the head of Leo does now!
The star at the bottom of the question mark will be the star, which at
present is the top right hand star of the "W".
During the same time "The Plough" will have become almost a
straight line. Of course, during this time, precession due to the Earth's
wobble will be in its fourth period of rotation.
in Strange Places
Trudy E. Bell
Red star, blue star, big star, small star-planets may form around
virtually any type or size of star throughout the universe, not just around
mid-sized middle-aged yellow stars like the Sun. That's the surprising
implication of two recent discoveries from the 0.85-meter-diameter Spitzer Space
Telescope, which is exploring the universe from orbit at infrared (heat)
wavelengths blocked by the Earth's atmosphere.
At one extreme are two blazing, blue "hypergiant" stars 180,000
light-years away in the Large Magellanic Cloud, one of the two companion
galaxies to our Milky Way. The stars, called R 66 and R 126, are respectively 30
and 70 times the mass of the Sun, "about as massive as stars can get,"
said Joel Kastner, professor of imaging science at the Rochester Institute of
Technology in New York. R 126 is so luminous that if it were placed 10 parsecs
(32.6 light-years) away-a distance at which the Sun would be one of the dimmest
stars visible in the sky-the hypergiant would be as bright as the full moon,
"definitely a daytime object," Kastner remarked.
Such hot stars have fierce solar winds, so Kastner and his team are
mystified why any dust in the neighborhood hasn't long since been blown away.
But there it is: an unmistakable spectral signature that both hypergiants are
surrounded by mammoth disks of what might be planet-forming dust and even sand.
At the other extreme is a tiny brown dwarf star called Cha 110913-773444,
relatively nearby (500 light-years) in the Milky Way. One of the smallest brown
dwarfs known, it has less than 1 percent the mass of the Sun. It's not even
massive enough to kindle thermonuclear reactions for fusing hydrogen into
helium. Yet this miniature "failed star," as brown dwarfs are often
called, is also surrounded by a flat disk of dust that may eventually clump into
planets. (Note: This brown dwarf discovery was made by a group led by Kevin
Luhman of Pennsylvania State University.)
Although actual planets have not been detected (in part because of the
stars' great distances), the spectra of the hypergiants show that their dust is
composed of forsterite, olivine, aromatic hydrocarbons, and other geological
substances found on Earth.
These newfound disks represent "extremes of the environments in
which planets might form," Kastner said. "Not what you'd expect if you
think our solar system is the rule."
Hypergiants and dwarfs? The
Milky Way could be crowded with worlds circling every kind of star
imaginable-very strange, indeed.
Keep up with the latest findings from the Spitzer at www.spitzer.caltech.edu/
For kids, the Infrared Photo Album at "The Space Place":
introduces the electromagnetic spectrum and compares the appearance of common
scenes in visible versus infrared light.
article was provided by the Jet Propulsion Laboratory, California Institute of
Technology, under a contract with the National Aeronautics and Space
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Secretary Phil Berry 01892 783544
Any material for inclusion in the May Newsletter should be with the Editor by April 28th 2006
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