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The SOCIETY for POPULAR ASTRONOMY
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Electronic News Bulletin No. 241 2008 March 30
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Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is Britain's liveliest astronomical society, with
members all over the world. We accept subscription payments online
using our secure site and can take credit and debit cards. You can
join or renew via a secure server or just see how much we have to
offer by visiting http://tinyurl.com/kogyx



POSSIBLE NEW UK IMPACT SITE
By Alastair McBeath, SPA Meteor Section Director

In mid 2002, a series of concentric ring-structures found buried in
sedimentary rocks, centred around 130 km offshore of Filey, North
Yorkshire, was announced as a probable impact crater, named
Silverpit, dating to circa 65-60 million years ago, near the end of the
Cretaceous geological period (see ENB 106). It remains uncertain if
this structure was due to an impact or not. Now, for the first time since,
a fresh possible UK impact site has been identified, by teams led by
Ken Amor of Oxford University and John Parnell of Aberdeen University,
as reported in the latest issue of the journal "Geology". The new site is
believed to be centred in The Minch off northwestern Scotland, between
Loch Broom near Ullapool and the Isle of Lewis in the Outer Hebrides,
and is far older than the date suggested for Silverpit, estimated at
around 1,200 million years, in the Precambrian period. The evidence
for this lies in some of Britain's very oldest rocks, which outcrop in the
Ullapool/Loch Broom area, especially a curious rock bed of angular
fragments set in a fine-grained matrix, up to 12m thick, called "Stac
Fada". This forms a characteristic feature in the rocks along a ~50
km-long curve of the near-coastal lands from Loch Ewe to the southern
edge of Eddrachillis Bay. The Stac Fada rocks separate older sandy
sediments, thought to have been laid down by meandering stream and
river channels on low-lying ground, from younger rocks which seem
indicative of a shallow lake environment, all probably deposited in a
semi-arid region (this part of Britain at the time is thought to have been
at around 15 degrees north latitude).

The Stac Fada bed has been interpreted in the past as due to some
form of ancient volcanic activity, perhaps an ash- or mud-flow, but likely
involving quite some violence to enable it to contain pieces of both
volcanic and pre-existing country rocks from the area the volcano
erupted. However, no such volcano has yet been identified, and it is
curious no other volcanic strata of similar dates occur in the rocks
nearby. This latest work reinterprets the stratum as instead due to the
ejecta blanket thrown out from a major impact, perhaps the largest one
known from the British Isles, citing in support the discovery of elevated
levels of the mineral iridium, often found associated with extraterrestrial
impacts, and microscopic shock fractures in some of the rock
fragments, which are again typically found in impact-related deposits.
This is certainly a plausible explanation, including for why there is only
one such rock bed. Unfortunately, elevated iridium quantities are
sometimes found from terrestrial volcanic activity too, while a violent
volcanic explosion needed to shatter the rocks into angular pieces,
might also have left similar shock fractures. The problem is complicated
further because of the great age of the rocks. This means they have
been subjected to a huge range of geological processes since they
were formed, which may have contributed to their current state. There
are a number of major ancient faults all across western Scotland for
instance, one of which completely severs the southern limit of the Stac
Fada bed outcrops. Movement on such fault lines can cause shock and
stress fractures in the rocks. Even the nature of the original land surface
the impact struck (if it was one) mentioned here is rather tentative. All
of this geological activity means the crater may no longer exist, or it
may not be where a superficial examination of the present facts might
indicate (something which may also explain the lack of a volcano,
though not necessarily the absence of other volcanic rock deposits).
Until such a crater is found, this is liable to remain an unconfirmed, if
reasonably plausible, explanation for the Stac Fada rocks. For more
information on this area in the Precambrian, see pages x and 5-7 of
the Geological Society's Memoir No.13, "Atlas of Palaeogeography
and Lithofacies", edited by J C W Cope, J K Ingham & P F Rawson
(1999 revised reprint).


STEVE EVANS
By Alastair McBeath, SPA Meteor Section Director

Further to the brief obituary for Steve Evans in ENB 240
( http://tinyurl.com/279agj ) who died on March 7th, several people have
requested more information on Steve's work with the Meteor Section.
Some of his images are available on the meteor pages of the SPA
website, as part of various reports, especially those on the Leonids for
2001 and 2002. The 2001 report ( http://tinyurl.com/2ca8t2 ) has some
personal recollections from him of his Arizona expedition, three
composite bright Leonid images caught using his video system, and a
link to a video clip of the best of those. The 2002 report
( http://tinyurl.com/2yueyf ) has two more composite video images, some
notes from his expedition to Spain in 2002, and also details of a
combined radio-video-visual analysis which included his data. Other
notes on his activities are presently only available in printed form, but I
can provide an electronic text copy of his personal recollections from
the Leonids between 1998-2002, which formed part of the Section's
display at the inaugural SPA Convention in 2005, on request.


RECENT FIREBALL NEWS
By Alastair McBeath, SPA Meteor Section Director

As regular visitors to the SPA website will be aware, continued
problems in making updates there mean the Recent Fireball Sightings
page has not been amended for the last couple of months, and notes
on all the latest fireball reports to the Section from the UK and nearby
have been given in the ENBs instead from February and March. As
there will be a break in the regular ENBs now till late April, please check
the SPA's Observing Forum for any fresh fireball updates after this
during April.

Changes since last time have been two more sightings of the February
11-12, ~20:55 UT fireball also imaged from Holland, bringing the tally
of reports on it to 22. Three new meteors have been reported since
ENB 240 too:

Date Time (UT) Magnitude and Notes Observed from
08/03/16-17 20:39 -4 Isle of Man
08/03/17-18 ~22:00 Bright Nottinghamshire
08/03/18-19 00:09 Very bright Fife

Additional fireball observations (a fireball is any meteor that reaches at
least magnitude -3) made from Britain or places nearby are always
welcomed by the SPA Meteor Section, whether of the above meteors or
not. Details to send are outlined on the "Fireball Observing" page of the
SPA website, at: http://tinyurl.com/l62fh .


METEOR PROSPECTS FOR APRIL
By Alastair McBeath, SPA Meteor Section Director

Problems with the website mean a more detailed look at April's meteor
activity than usual is given here too.

For most of the month from Britain, there is just the "light drizzle" from
the Antihelion Source to look out for, apart from the omnipresent
sporadics. Antihelion meteors radiate from a roughly oval region, about
30 degrees in RA (two hours) by 15 degrees in Dec, which lies roughly
opposite the Sun in the sky, hence its name. The actual Source's centre
is about 12 degrees east of this point. Video results suggest it is
active virtually throughout the year, producing generally low rates.
Radiant centre positions for this area are provided in the Section's
Meteor Showers List, available via the meteor homepage, at:
http://tinyurl.com/2m335d . In April, this radiant centre tracks from
south-east Virgo right across Libra, an area that is on-view for most of
the night, culminating around 01h UT. In general, one or two meteors
per hour is a good level of Antihelion activity, but early and late April
were identified in recent International Meteor Organization (IMO)
analyses as being among the annually better times for such rates. Even
so, this "improved" activity is liable to bring Zenithal Hourly Rates (ZHRs)
no better than 4, and for a time after mid April till the last few days, this
may drop to just 2. However in past times, occasional very bright
meteors had been attributed to this source under its former name of
"Virginids", and observations to check on it are recommended
whenever there is no Moon after mid-evening. Antihelion meteors are
of medium speed.

During this "low" for Antihelion meteors, we have the compensation of
the Lyrids, active from April 16-25, reaching a peak on April 21-22,
perhaps around 05h UT, but almost certainly at sometime between 21h-
08h UT then. Though this extended interval is partly overnight for Britain,
the waning gibbous Moon around Libra (full on April 20) will be nicely
visible by the time the Lyrid radiant has risen to a usable elevation,
after 22:30 UT or so. This is not good news for visual observers! The
radiant's (and the Moon's!) visibility improves throughout the night, the
radiant at maximum lying about a Lyre's length (the distance from Alpha
- Vega - to Gamma Lyrae) southwest of Vega at 18h04m RA, +34
degrees Dec, and actually in Hercules, not nearly so close to Vega as
some people expect. The extended interval for the peak's timing is
based on the most recent detailed analysis of IMO data. The closer it
falls to the ~05h UT timing, the higher its ZHRs are likely to be, perhaps
20-25 or more. The average ZHR is 18, and tends to be lower the
further the maximum happens away from the "ideal" time. In general, the
peak is usually quite short, lasting no more than a few hours, but
occasionally more prolonged maxima, lasting for 8+ hours have been
seen, recently in 2000 and 2001, and rare strong ZHRs of up to 90 (last
in 1982 over the USA) may occur too. Thus, when there is little or no
Moon, sadly not including this year, the shower is always one to watch.
Lyrids are medium-fast meteors, and can be very bright sometimes.
Anyone wanting to brave the Moon in the hopes of spotting a few
should watch as much sky as is comfortably possible, facing away from
the Moon (perhaps best towards Ursa Major-Gemini-Leo). Hopefully,
the radio meteor observers will have better luck, though the shower is
not always easy to identify from the background rates even so.

Although the shower is unlikely to be visible from Britain, because its
radiant is around 07h20m RA, -45 degrees Dec, anyone travelling to the
southern hemisphere, and perhaps even radio observers further north,
are being encouraged to check on possible Pi-Puppid activity this year.
This is because the shower is a young one, first observed only in 1972,
and is produced by dust shed from Comet 26P/Grigg-Skjellerup, which
reached perihelion on March 23, just a month before we are due to
encounter its meteoroid stream. Previous returns near the comet's
perihelion passage have produced occasional brief showers with ZHRs
up to 40 (including 1977 and 1982). ZHRs of ~13 were noted in 1983
as well, the year after the comet was closest, but no activity was seen
in 2003 following the comet's last return in November 2002 (though
possible activity had been predicted). Dust trails laid down in 1937,
1942 and 1947 look set to be crossed this year, according to
independent theoretical work by professional astronomers Jérémie
Vaubaillon and Mikhail Maslov, which could produce some activity on
April 22. The most likely time is between 22:10 to 22:20 UT, when
ZHRs may be just 5-10 (Maslov) or maybe as high as 100-130
(Vaubaillon) from a combination of the two 1940s trails, but both
theorists suggest a high proportion of faint meteors will be present,
which could render the event nonexistent visually, given the bright Moon
afflicting the Lyrids will be similarly problematic for the Pi-Puppids. The
1937 trail should be met around 14:10 UT on April 22, with ZHRs
perhaps ranging from zero to 40, again likely to be of mostly faint
meteors (if any appear at all). This could give radio observers a
particular advantage, as some radio meteor systems preferentially
pick up many fainter meteors. Another possible time for activity may be
when the Earth passes closest to the comet's current orbit, around 10h
UT on April 23 (which is little better from the moonlight perspective).
Past Pi-Puppid returns have sometimes seen very weak suspected
activity present from April 15-28, while any shower meteors will be
characteristically very slow moving; their atmospheric entry velocity is
around 18 km/sec (the full range of possible meteor velocities is 11 to
72 km/sec).

Sparking into life by late April are the Eta Aquarids, beginning in the
moonlight around April 19, when their radiant lies a degree or two
south of the star Beta Aquarii, at RA 21h32m, Dec -7 degrees.
Unfortunately, this area rises only as morning twilight commences even
from southern Britain then, so the shower is always a very tricky subject
from here. Late April's waning Moon will be a decreasing nuisance at
least. Any Eta Aquarids will be very long-pathed, swift moving, and
rising up from the eastern horizon towards the end of the night during
and after the Lyrids, but don't expect more than one - and that only if
you're very fortunate!


STORM ON VENUS
ESA

Observations of the south pole of Venus by Venus Express have revealed
an enormous structure with a central part that looks like the eye of a
cyclone, and changes shape within a matter of days. The eye is at the
centre of a 2000-km-wide vortex. It was discovered in 1974 by the
Mariner 10 spacecraft. There is a similar structure over the planet's
north pole, which was observed by the Pioneer Venus mission in 1979.
Venus Express scientists have been studying the structure in the
thermal infrared which reveals the temperature at the cloud-tops.
Seen at that wavelength, the core of the vortex appears very bright,
probably indicating that atmospheric gases are moving downward there,
creating a depression at the cloud-tops so we see a hotter region.

In 2006 June the vortex appeared hourglass-shaped, closely matching
the north polar region as seen by Pioneer Venus. Now we know that it
changes its shape within a matter of days, from orbit to orbit. An
image taken on 2007 February 26 shows a dipole shape at the centre of
the vortex, similar to that which had been observed previously. But
an image taken a mere 24 hours earlier shows the centre of the vortex
to be almost circular. At other times, it is typically oval.

Scientists are not sure what actually creates the vortex, but one
explanation is that atmospheric gases, heated by the Sun at the
equator, rise and then move poleward. In the polar regions, they
converge and sink again. As the gases moves towards the poles, they
are deflected sideways because of the planet's rotation. The dynamic
nature of the vortex is similar to behaviour observed in vortices on
Earth, including those observed at the centres of cyclones.


MARS, EARTH AND MOON FROM 'UNIQUE PLANETARY NURSERY'
University of Oxford

An international team of scientists has analysed 16 meteorites that
are believed to have fallen to Earth from Mars. They found that the
amounts of neodymium-142 that they contain are subtly different from
those of objects found in the asteroid belt. That isotopic
fingerprint suggests that the chemistry of the inner Solar System was
different even for elements that are hard to vaporise. The Earth,
Moon and Mars appear to have formed in a part of the inner Solar
System with a ratio of samarium to neodymium that is around 5 per cent
more than is found in the asteroid belt. It is that 'family
resemblance' that we see today when we compare oceanic basalts from
Earth with Moon rocks and Martian meteorites. Such differences may be
the result of the erosion of planetary crusts during formation events;
alternatively, the composition might have arisen from the sorting of
clouds of partially melted droplets or grains, known as chondrules.
The results suggest that the sorting of the elements that make up
the planets may have happened at a much earlier stage than had been
believed. It may even be that the sorting happened in the accretion
disc out of which some people think that Mars and the early Earth
first formed. The composition of those planets is inconsistent with
their simply forming out of large lumps of stony-meteorite material,
such as we see today in the asteroid belt.


MARS' VOLCANIC PAST
ESA

A new analysis of impact-cratering data from Mars indicates that the
planet may have undergone a series of global volcanic upheavals.
Those violent episodes brought lava and water to the surface,
sculpting the landscape that Mars Express looks down on today. The
work suggests that the sculpting of the Martian surface has not
proceeded in a steady fashion, as it does on Earth. Rather, it tends
to indicate that Mars has been wracked by violent volcanic activity
five times in the past, after an early supposedly warmer and wetter
phase, more than 3.8 billion years ago. In between episodes, the
planet has been relatively calm. The five volcanic episodes are
proposed to have occurred around 3.5 billion years ago, 1.5 billion,
400-800 million, 200 million, and 100 million years ago. The ages
have been estimated by counting the numbers of small craters that
appear on the landscape. The idea is simple: the older the surface,
the more craters it will have accumulated as meteorites of all sizes
have struck over the ages.

During the volcanic episodes, eruptions of lava flowed across Mars.
The internal heat generated by the volcanic activity also caused water
to erupt from the interior, causing wide-scale flash-flooding. As for
why Mars behaves like that, models suggest that the planet has been
trying to establish a system of plate tectonics, as there is on Earth
where the crust is broken into slowly moving plates. On Mars, the
volcanic episodes represent the planet almost achieving, but not
actually attaining, plate tectonics -- and the volcanic episodes might
not be over. Far from revealing a tectonically dead world, Mars
Express is exposing a place of subtle activity that could still erupt
into something more spectacular.


SALT DEPOSITS ON MARS
Arizona State University

Scientists using a Mars-orbiting camera have discovered about 200
individual places in the Martian southern hemisphere that show
spectral characteristics consistent with deposits of chloride minerals
(salts), that may show where water was once abundant. The deposits
occur in the middle to low latitudes all around the planet within
ancient, heavily cratered terrain; they range in area from about one
to 25 square kilometres, and because they appear to be disconnected
from each other researchers don't think that they all came from one
big, global body of surface water. Instead, they could have come from
ground water reaching the surface in low spots. The water would
evaporate and leave mineral deposits, which built up over time. The
scientists think that the salt deposits formed mostly between about
3.9 to 3.5 billion years ago. Several lines of evidence suggest that
at that epoch Mars had periods when the climate was substantially
wetter and warmer than it is today..


CASSINI'S FLY-BY OF ENCELADUS
Jet Propulsion Laboratory

The Cassini spacecraft has passed close to Saturn's moon Enceladus,
flying at about 15 km/s through geyser-like jets. The spacecraft
snatched up samples that may provide evidence as to whether liquid
water exists under the icy crust of Enceladus. The geysers emanate
from fractures near the moon's south pole, and eject water vapour at
approximately 400 m/s. The new data provide a much more detailed look
at the fractures and will give a significantly improved comparison
between the histories of the moon's north and south poles. Compared
to much of the southern hemisphere on Enceladus and to the south polar
region in particular, the north polar region is much older and pitted
with craters of various sizes. The craters are seen at different
stages of disruption and alteration by tectonic activity, and probably
from past heating from below. Many of the craters seem to be sliced
by small parallel cracks that appear to be ubiquitous throughout the
old cratered areas on Enceladus.

This was the first of four Cassini fly-bys of Enceladus this year.
Future ones may bring Cassini even closer to the surface of Enceladus.
Cassini will complete its prime mission, a 4-year tour of Saturn, in
June. A proposed extension to the mission would include seven more
Enceladus fly-bys.


OCEAN MAY EXIST BENEATH TITAN'S CRUST
NASA/Jet Propulsion Laboratory

Cassini has discovered evidence that points to the existence of an
underground ocean of water and ammonia on Saturn's moon Titan.
Members of the scientific team viewed images collected by Cassini's
synthetic-aperture radar during 19 separate passes over Titan in
2005-2007. The radar can see through Titan's dense, methane-rich
atmospheric haze, detailing surface features and establishing their
locations on the moon's surface. From the early observations, the
scientists established the locations of 50 unique landmarks on Titan's
surface, and then searched for the same landmarks in later fly-bys.
They found that prominent surface features had shifted from their
expected positions by up to 19 miles. A systematic displacement of
surface features would be difficult to explain unless the moon's icy
crust were decoupled from its core by an internal ocean, making it
easier for the crust to move. The researchers believe that about
100 km beneath the ice and organic-rich surface is an internal ocean
of liquid water mixed with ammonia.


ANCIENT ASTEROIDS FORMED AT SOLAR SYSTEM'S START
University of Maryland

Using visible and infrared data collected from telescopes on Hawaii's
Mauna Kea, scientists have identified three asteroids that appear to
be among our Solar System's oldest objects and are relatively
unchanged since they formed some 4.55 billion years ago -- before the
oldest meteorites ever found on Earth. It is thought that the Solar
System started from a disc-shaped cloud of hot gas, the solar nebula.
When gases on the edge of the nebula began to cool, the first
materials to condense into solid particles were rich in the elements
calcium and aluminium. As the gases cooled further, other materials
also began to condense, and eventually the different types of
particles clumped together to form the common building blocks of
comets, asteroids, and planets. Astronomers have thought that at
least some of the Solar System's oldest asteroids should be more
enriched in calcium and aluminium, but, until the current study, none
had been identified.

Meteorites found on Earth do contain small amounts of bright white
ancient materials, the so-called calcium, aluminium-rich inclusions,
which can be as large as a centimetre in diameter. Scientists, in
fact, long have used the age of CAIs to define the age of the Solar
System. The fall of the Allende meteorite in 1969 initiated a
revolution in the study of the early Solar System; it was then that
scientists first recognized that the white inclusions found in that
meteorite matched many of the properties expected of early Solar-
System condensates.


VANGUARD 1 CELEBRATES 50 YEARS IN SPACE
ScienceDaily

The Vanguard I satellite celebrates its 50th birthday this year. Its
launch on 1958 March 17 from Cape Canaveral, Florida, culminated the
efforts of America's first official space-satellite programme, begun
in 1955 September. The first solar-powered satellite, Vanguard I has
the distinction of being the oldest artificial satellite orbiting the
Earth. Its predecessors, Sputniks I and II and Explorer I, have since
fallen out of orbit. Vanguard I is 6 inches in diameter and weighs
about 3 pounds. Its small size, compared to the Soviet's 200-pound
Sputnik I, caused the then Soviet Premier Nikita Khrushchev to dub it
'the grapefruit satellite'.

In the 50 years following Vanguard's launch the satellite has made
nearly 200,000 revolutions of the Earth and travelled 5.7 billion
nautical miles, one and a half times the distance to Pluto. In that
time it has provided a wealth of information on the size and shape of
the Earth, and set a number of space records as well. Vanguard I
introduced some of the technology that has been applied in other
U.S. satellites. For example, it proved that solar cells could be
used for several years to power radio transmitters. Vanguard's solar
cells operated for about seven years, while conventional batteries
used to power another onboard transmitter lasted only 20 days. When
it was launched 50 years ago, it was estimated that the satellite's
life expectancy would be about 200 years. Since then, scientists have
extended the estimate to 2000 years.


GRAINS OF SAND FOUND AROUND DISTANT STARS
Rice University

In a finding that sheds light on how Earth-like planets may form,
astronomers have reported the first evidence of small sandy particles
orbiting a young star at about the same distance as the Earth orbits
the Sun. In previous studies, astronomers have used infrared heat
signals to identify microscopic dust particles around distant stars,
but the method does not tell the sizes of the particles or whether
they orbit near the star, like the Earth does the Sun, or much further
away at distances more akin to those of Jupiter and Saturn. In the
new study, astronomers used reflected light from the sand itself to
confirm the Earth-like orbit of grainy particles around a pair of
stars called KH-15D in the constellation Monoceros. The stars are
about 2,400 light-years from Earth in the Cone Nebula, and they are
only about 3 million years old. The researchers found that the Earth
has a nearly edge-on view of KH-15D. From our perspective, the disc
blocks one of the stars from view, but its twin has an eccentric orbit
that causes it to rise above the disc at regular intervals. The
eclipses allow astronomers to study the system with the star there and
with the star effectively not there. It is a very fortuitous
arrangement because when the star is there it is so bright that the
sand cannot be seen. Because of how the light is being reflected
there are opportunities to make observations about the chemical
composition of the sand-like particles.


METHANE DETECTED ON EXTRASOLAR PLANET
Hubble ESA Information Centre

Methane has been found by the Hubble telescope in the atmosphere of
the Jupiter-sized extra-solar planet HD 189733b, which is located 63
light-years away in the constellation Vulpecula. Although methane has
been detected on most of the planets in our Solar System, this is the
first time any carbon-containing molecule has been detected on a
planet of another star. HD 189733b is a 'hot Jupiter'-type planet,
so close to its parent star that it takes only just over 2 days to
complete an orbit; its atmosphere is at 900°C, about the melting point
of silver.


MOST DISTANT OBJECT SEEN WITH THE unaided EYE
NASA/Goddard Space Flight Center

A powerful stellar explosion detected March 19 by the Swift satellite
has broken the record for the most distant object that might have been
visible, however briefly, with the unaided eye. The explosion was a
gamma-ray burst. Most gamma-ray bursts are now thought to occur when
massive stars run out of nuclear fuel. Their cores collapse to form
black holes or neutron stars, releasing an intense burst of
high-energy gamma-rays and ejecting particle jets at nearly the speed
of light. When the jets plough into surrounding interstellar clouds,
they heat the gas, often generating bright afterglows. Gamma-ray
bursts are the most luminous explosions in the Universe since the Big
Bang.

Swift's burst-alert telescope picked up the burst on March 19 and
pinpointed the coordinates in the constellation Boötes. Telescopes
quickly moved to observe the afterglow, and several ground-based
telescopes saw the afterglow brighten to visual magnitudes between 5
and 6. Later that evening, ground-based telescopes measured the
burst's redshift at 0.94 which translates into a distance of 7.5
billion light years, meaning that the explosion took place 7.5 billion
years ago, a time when the Universe was less than half its current age
and the Earth had yet to form. The burst's optical afterglow was 2.5
million times more luminous than the most luminous supernova ever
recorded, making it the intrinsically brightest object ever observed.
The most distant object that can have been seen by the unaided eye
normally is the galaxy M33, a relatively short 2.9 million light-years
away.


ENB MODERATOR PUBLISHES 200th PAPER IN 'THE OBSERVATORY'

Many congratulations to Professor Roger Griffin of the Institute of
Astronomy, Cambridge on the remarkable achievement of publishing his
200th paper on 'Spectroscopic Binary Orbits from Photoelectric Radial
Velocities', which will appear in the June edition of The Observatory
journal. The series, which began in 1975, has appeared in each and
every issue since then. Many of the observations have been carried
out with what is thought to be the UK's largest telescope -- the
36-inch at Cambridge. Despite the fact that conditions for
astronomical observing in the UK are often far from perfect, Professor
Griffin has typically observed on average about 130 nights each year.
He has also been fortunate enough to have 16 seasons' use of the
200-inch Hale telescope at Palomar from 1971 until 1986, and many trips
to the Haute-Provence observatory. The measurement of radial
velocities can be used to determine the orbits of binary stars that
are too far away to separate optically. Most known extra-solar
planets have been discovered by the same method.

When he is not at the observatory, Professor Griffin enjoys running
and has completed six London Marathons, coming second in his age-group
the last two years. He has also has been on mountains, including
Kilimanjaro in 2005. For the past seven years, Professor Griffin has
worked behind the scenes to ensure that these Electronic News
Bulletins are of a high standard.


Owing to holidays the next edition of the ENB will not appear until
April 27.

The SPA Electronic News Bulletins are sponsored by the Open University.
Bulletin compiled by Clive Down


(c) 2008 the Society for Popular Astronomy


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