WADHURST ASTRONOMICAL SOCIETY
APRIL NEWSLETTER 2004
INDEX: MEETINGS, OTHER NEWS, CONTACTS
talk by Dr. Robert Smith on Wednesday 17th March
Smith is a lecturer in Astronomy at the University of
Sussex, with particular interest in Spectroscopy and
Interacting Binary Stars.
introduced the talk by saying that although planets
around stars systems beyond the Solar System cannot
be seen directly, over a hundred planets have been detected
around ninety stars.
Of these planets, all but one have been discovered
by monitoring the "wobble" of the host star.
At present, the sensitivity of detecting methods
limits the size of these planets to Jupiter of even
Saturn sized objects.
defined a star as greater than 0.8 solar masses (about
80 Jupiter masses), powered Hydrogen fusion, with Brown
Dwarfs (about 13 Jupiter masses) powered by some Deuterium
one really agrees, but it is suggested that a planet
is anything less than 13 Jupiters.
then looked at various methods used to search for Extra
- both ground based and space missions using
radio are investigating, but there have been no successful
results so far.
of the wobble of a star have produced many positive
finds, although he went on to say that this method requires
incredibly accurate position measurements, using Quasars
as the most accurate background reference, as in any
appreciable time, they move less than anything else
in the sky. Using this method Sirius B was one
of the first stars to be detected as having planet orbiting
Velocity is another method being used in the search. This method looks at the Doppler
change as the star rotates with its companion large
requires incredibly accurate Doppler measurements, and
its greatest chance of detection is if the plane of
the orbit is in line with the observer.
Many stars appear to vary in this way because
of the nature of stars gaseous changes, so the planet
would have to be relatively quite large to be distinguishable.
detection involved the orbit of the relatively large
planet transiting the parent star as seen from by the
last method Richard referred to was Gravitational Lensing.
The light from a distant background star could
be diffracted by the gravitational effect of a closer
this closer star has a suitable planet orbiting it,
the light from the distant star as the closer star passes
in front of it would show a "blip" on the
The big disadvantage of this method is that the
pass may only be seen once due to the star's movement,
and could not be verified by observing other blips.
The size of the peak of the blip would indicate
the size of the nearer stars planet.
concluded this part of his talk with the story of one
of his graduate students; Kevin Apps who has became
noted for much work on the detection of Extra Solar
had emailed Marcy and Butler in the USA whose work was
already well known, requesting a list of the 300 target
stars for the 10 metre Keck telescope on Mauna Kea.
He received the list from Geoff Macey, but found
30 of these stars to be unsuitable because they were
either too big or were binary stars.
Richard was astonished to discover that Kevin
had told Geoff Macey of these, who then asked for suggested
Kevin then provided 30 new targets and now Macey
began to take Kevin seriously, and he went on increasing
the list by another 400.
Apps went on to observe at the Lick observatory in April
1999 and then in August 1999 he observed with the Keck
finds (to last year) had increased to 103 planets with
masses of 0.12 to 16.9 Jupiter masses.
36 of these were "hot Jupiter" type
planets, which orbited very close to the parent star.
Two thirds of the planets had eccentricities
greater than Jupiter and 12 systems had multiple planets.
the search has only been in progress for a few years,
only planets with periods less than this time can be
determined, and as time goes on, more planets are certain
to be discovered.
one transit type orbit had been discovered and confirmed
by the Hubble Space Telescope.
The orbit took just 3.5 days, and the drop in
light caused by the planet passing in front of the star
lasted only 0.1 of a day.
There is another possible transit type planet
with an orbit of 1.2 days, but is waiting to be confirmed.
concluded this talk with a brief look to the future. Continuing searches using radial
velocity methods hope to find lower mass planets.
Gravitational Lensing is statistical only.
Direct imaging is difficult from the ground,
but space-based astrometry will be possible with the
launch of "Darwin" possibly in eight years
incorporates 6 space craft fixed relative to each other
very accurately, and will use high resolution infra-red
suggested a worthwhile web site called OPM (l'Observatoire
de Paris et Meudon) www.obspm.fr
where there was a lot of useful astronomical information
to be found.
This was a well constructed talk of what could have been a complicated subject, but was explained in a pleasant and interesting way using computer graphics and a digital projector.
At the next meeting on Wednesday April 21st
2004, the speaker will be Peter Gill.
His talk is called "Talk on the Moon".
As usual, the meeting will be held in the Drama
Studio at Uplands College.
The doors open at 7.15 and the meeting starts
at 7.30 prompt.
DAVID SCOT - APOLLO 15
Paul Treadaway has sent an interesting email:
I visited the Observatory Science Centre at Hertmonceux, the former home of the Royal Greenwich Observatory. We were talking with Sandra Voss firstname.lastname@example.org 01323 832731) and she says that astronaut David Scot will be giving a talk on May 13th, and signing his book. David was aboard Apollo 15 and drove on the moon. The event is a late entry, not shown in the function list (yet); see www.the-observatory.org , and is only £3 for entry.
There will be Observing Sessions on the following Fridays:
The sessions meet at 7.30 pm in the Crow and Gate pub, about a mile south of Crowborough on the A26 main Uckfield road. Then at 8.00 pm the group move onto Ashdown Forest with Sean’s and the Society’s telescopes and possibly others.
suggests that interested members phone him between 6.00
pm and 7.00 pm to make sure the session is going ahead.
The Treasurer now reports that we now only have
four of last year's members who have not yet renewed
their subscriptions, and we are pleased to welcome two
Michael Berks and Jan Drozd. We hope they will enjoy their membership with us.
has been instrumental in arranging for the Isle of Man
Astronomical Society to get a 28" mirror for the
Foxdale Observatory site, IOM.
The mirror had been the property of Duncan's
friend Harold Robin and Duncan was the 'go between'
for both the Manx society and the Robin's family.
I should mention that Duncan had originally suggested
that perhaps the WAS should take on the big mirror but
it was realised in the conversations that he had with
myself and others that this could well be 'a poisoned
know that it gave Duncan great pleasure seeing the mirror
off to the financially well-supported society in the
Incidentally, it was a mirror from Harold Robin
that was installed into the observatory at the Isle
of Thorns site.
Duncan was very much involved with this project.
I am sure that Duncan would wish me to make clear
that the installation of the equatorial mount for the
18" however was not his responsibility for if it
had been perhaps the builders would not have made such
a drastic error with regards the setting of the pier!
Duncan and his wife Thelma often participated
in out reach programs for the public and the disabled.
At the Harold Robin Community Study Centre, Isle
of Thorns, Duncan would give demonstrations of mirror
making techniques and explain the rather esoteric Foucault
test to people of all ages and abilities.
Duncan was very saddened when the site, previously
operated by Sussex University was taken over by the
Cats Protection League.
Duncan knew that it was only a matter of time
before free access to the telescope would be curtailed
by the new owners who did not appreciate nor indeed
want a research telescope.
In spite of much canvassing and letter writing,
Duncan's worst fears have sadly been realised.
I recall that Duncan was hoping that perhaps
some of the projects he was involved in might continue
at the at Ringmer College site near Lewes.
On a happier note, Duncan, Thelma and Christine
Jones voluntarily operated a small organisation called
Basically this group encouraged schools to build
idea was for children working with teachers and parents
would actually grind, polish and figure telescope mirrors
to be installed into telescope tubes.
I understand that it was primarily Duncan's guiding
hand that steered these projects.
Several schools in the county of East Sussex
have benefited from this.
Before his illness Duncan was a fully participating
member of the society.
He and Thelma enjoyed the fêtes and shows at
both Wadhurst and more recently Speldhurst.
Duncan would always attend committee meetings
and the committee in turn felt that he should be asked
if he wished to take the position of 'technical advisor'.
Given his willingness not only to listen but
also to help members, this was a perfect role for him.
Many members of the Society will remember Duncan
offering the use of his extensive metalworking equipment
to anybody who was building a telescope or parts thereof.
He also offered technical advice to anybody who felt
they needed it. Duncan would always carry with him a
note pad and pencil and would doodle magnificent near-technical
drawings of focuser mounts, spiders (secondary mirror
supports) and these drawings would then eventually make
their way into one of three engineering workshops at
his home in Rotherfield.
Duncan made several items for the society telescope
including the expertly crafted spider.
It was in his Aladdin's caves of engineering
that Duncan and his colleagues would produce bespoke
high light intensity devices to be used by medical researchers
in the field of cancer diagnosis and treatment.
The interest in astronomy was of course a lifetime
pursuit and it is only very recently that his permanently
sited garden telescope has been taken down from its
plinth in his garden.
I vaguely recall that this telescope has been
in use from his garden for over 50 if not 60 years!
I am pleased to tell you that Duncan made a gift
of this telescope to his former old school, Cranbrook.
I hope they too will enjoy safe observations
of the sun with its un-silvered mirrors.
Duncan will be sadly missed and I extend my sympathies
to Thelma and her family.
Chairman: Murray R. Barber
Treasurer: Ian Reeves 01892 784255
Web Site: Michael Harte
Obs: Sean Tampsett
LAST DATE FOR COPY FOR INCLUSION IN THE NEXT NEWSLETTER 30 APRIL 2004
GO TO INDEX