WADHURST ASTRONOMICAL SOCIETY
APRIL NEWSLETTER 2005
INDEX: MEETINGS, OTHER NEWS, CONTACTS
Craig Telescope at Wandsworth
by Greg Smye-Rumsby on Wednesday 16th March 2005.
gave a very amusing and animated presentation using excellent computer graphics,
telling of a long forgotten leviathan of a telescope built in the mid 19th
For quite some
time, Greg had collected data and built up a dossier of information on long
since vanished observatories and telescopes and when he recently came across a
reference to a telescope tower built on Wandsworth Common that had finally been
removed in 1877, he remembered the name and became sufficiently interested to
research any information he could from archives and references in the local
library. Very little was known of
tower or of the telescope itself.
He did discover that the telescope had been built by the Reverend John
Craig and began by finding out all he could about this apparently very
persuasive and overbearing cleric, born in Ireland in 1805.
Craig presided over the rebuilding of All Saints Church, although owing to his
convincing manner left out the tower, which had to be added some years
later. Craig's other interest was
astronomy and he acquired a 24-inch lens for an astronomical telescope. At the time this was the largest lens in
that Craig had approached the Fourth Earl Spencer who owned Wandsworth Common
and managed to obtain the use of part of the Common for £1 (£52 by today's
standards), but for a limited period of 14 years. After complaining that this
was not long enough in astronomical observatory terms, it was agreed that the
land could be used in perpetuity until it could no longer be used for the
purpose of observing.
After some initial research, Greg
discovered a drawing made by Beard Engineering but there were too many
inconsistencies for it to half worked.
But it did reveal that the engineer for the telescope and the tower was
William Cravat. Then a much more
precise sketch by a man called Sargent revealed that there had been a round
tower with a rotating cap on top from which a chain hung down with a large metal
loop through which the 85 feet long mild steel telescope tube could be supported
and raised up and down. The
eyepiece end of the telescope was mounted on a dolly that could be moved round
the tower on a track. The drawing
also showed a large due cap and a small flap towards the top of the tube, which
it is thought could be opened to allow hot air inside the tube to escape.
There were two
grill-covered windows at the top of the tower, through which Greg believes
operators would have been able to communicate with people on the ground when
aligning the telescope.
On a track
running round the base of the tower was box at the bottom of the chain, and
after some thought by Greg's brother proposed that this box was in fact a bogey
into which the chain would be stored as the telescope was raised and
It has been calculated that the maximum
angle the telescope could have been raised to would have been 74 degrees and the
minimum must have been 4 degrees.
One alarming fact
was that it was thought that the tower itself had no foundations as such!
delighted when he was approached by the television "Time Team" programme who
wanted to perform a scientific archaeological dig and he had no hesitation in
suggesting the site of the Craig Telescope.
location was unknown and they had to approach Wandsworth Council and National
Heritage for permission to carry out the dig. After researching old maps of about 1862
an observatory was found in the grounds of what had been Burntwood House in the
southwest corner of the Common.
Then on the more precise Whitbread Map of 1871 a "Telescope" was marked
inside the junction of Routh Road and Lyford Road.
granted and Greg was asked where a test trench should be dig. The land had never been built on before
or since and Ground Penetrating Radar was requested which revealed a certain
amount of compaction but since there had been no foundations all they found was
one brick from the tower, a roof tile and one sheered off nut. The rest of the land must have been
pretty well cleared after being dismantling in 1877.
Probably as a
result of the programme, Greg was shown the only photograph of the tower and
telescope taken by Geoffrey Bevington in 1852, confirming the accuracy of
Sargent's drawing, and also showing buildings in the background that finally
showed the most precise position of the tower.
The focal length of the 24-inch lens was 23164.8 mm with a focal ratio of 38. Slung beneath the main tube was a 6-inch finder with a focal length of 1524 mm, focal ratio 10, and known eyepieces for the 3-ton telescope where between 125 mm and 750 mm.
The outer track
for the eyepiece dolly had a radius of 52 feet, but evidence for this was not
discovered until a recent return visit by Greg when he discovered some remains
across an overgrown footpath they had all been using throughout the dig.
to the main lens? Greg suggested it
could now be a rather nice coffee table somewhere!
The next Society
meeting is on Wednesday 20th April 2005 when the speaker will be John Murrel
talking about "Virtual Observatories - fireside astronomy".
The meeting takes
place as usual in the Drama Studio at Uplands College, Wadhurst, and commences
at 7.30 pm.
Ian Reeves has
been very busy since taking on the post of Society Secretary and has already
completed the programme of speakers for the rest of this year. Advance announcement of these talks is
May 2005. The speaker will be Alan
Smith from Horsham whose talk is called "Deep Sky for all Seasons"
June 2005. Dr. Andrew Coates from
the Mullard Space Science Laboratory gives a talk called "The Cassini - Hygens
Wednesday 20th July
2005. Konrad Malin-Smith will be
guiding us around "Pulsars".
There will be no
meeting in August.
September 2005. Alan Drummond will
be giving a talk entitled "Perception in Astronomy".
October 2005. Peter Parish
introduces us to "Planets and Small Telescopes".
November 2005. Gilbert
Satterthwaite talks about Sir George Airy and nineteenth century instruments in
his talk called "Positional Astronomy".
Wednesday 14th December 2005. PLEASE NOTE THAT THIS MEETING HAS BEEN BROUGHT FORWARD A WEEK! (Instead of the third Wednesday, this will be the second Wednesday in the month) On this occasion the speaker will be Norman Walker talking about "Getting the Measure of the Stars).
There is to be
a meeting of the whole Committee at 8.00 pm on Monday 11th April 2005 at the
Abergavenny Arms in Frant, just two miles south of Tunbridge Wells on the A267
road. If any members of the Committee
wish to raise any particular points, could they let the Secretary, Ian Reeves,
know before hand if possible.
member of the Society is also very welcome to come along.
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OUR NEW TREASURER AND
At the close of
the 16th March 2005 meeting a fresh Bank Mandate was duly completed to formally
include Michael (Mike) Wyles, (elected to the Committee on the 15th December
2004) as our new Treasurer.
A few Society
members have not yet renewed their membership for the current session, which
began in November. Mike would be
delighted to accept a cheque for £15 for a single member or £20 for joint
membership either sent to him or at the next meeting. Cheques should be made payable to
Wadhurst Astronomical Society.
is 31 Rowan Tree Road, Tunbridge Wells, Kent TN2 5PZ.
THE NIGHT SKY IN APRIL
arrived and with it an extra hour of daylight! This means that the night-sky is also an
hour later as well, courtesy of the Government.
We have just
about lost the winter constellations now and the spring constellations are
appearing. Leo has become dominant
to the south with the group of stars making up the lion's head looking rather
like a reversed question mark, Regulus acting as the full-stop underneath. Regulus is a relatively hot star at a
distance of about 77 light years away and so has an apparent magnitude of 1.36
although its absolute magnitude us -0.52. (Absolute magnitude is worked out as
if the star was 10 parsecs away) If
Regulus was at the centre of our solar system it would be 130 times brighter
than our sun.
About 40 degrees
to the west is Procyon in the constellation of Canis Minor, a star looking very
much as our Sun would look at that distance. Procyon is 11 light years away.
Regulus and Procyon is a circular group of fainter stars. This is the head of the constellation of
Hydra, the water snake and is the longest constellation in the entire sky since
the tip of its tail is 70 degrees away to the south.
Corvus the crow
can be recognised by the four bright stars fairly low down in the southeastern
sky forming the shape of a kite.
interested in deep sky objects, M104 is just six degrees above the eastern-most
of these bright stars is called the Sombrero Galaxy. Although it has an integrated magnitude
of 8.3 it can be just made out with a pair of binoculars as a fuzzy shape. With a medium telescope, the shape of
the sombrero can just be made out, but with a CCD the line of dark matter
orbiting the galaxy becomes quite spectacular. The integrated magnitude is the
magnitude of a group of stars as if they were to be contracted down to one
point, so can be quite disappointing when compared to a true star of the same
Jupiter is just
another eight degrees to the northeast and is now an important part of the
Southern sky and is always worth observing with any telescope or
binoculars. The four Galilean moons
are Io which orbits closest, then Europa, Ganymede and Callisto and all can
easily be seen unless passing in front of or behind the planet. Even then it is sometimes possible to
see the moon passing above the planet with its shadow visible on the surface
The moon is full
on the 24th of April when illumination from the sun shows up Tycho's rays most
clearly. Tycho is the deep 85
kilometre diameter crater towards the south (In the lower part of the disk when
viewed through binoculars. Upper
part when viewed through an inverting astronomical telescope).
Many of the moons
features are best seen when the light of the sun is low on the lunar
horizon. For instance the
spectacular Apennine mountains on
the southern side of the Mare Imbrium, the large "sea" towards the north of the
moon's face is ideally seen on the 16th April. This range is about 700 kilometres
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Tim Bance 01732 832745
Reeves 01892 784255
Wyles 01892 542863
Publicity & Web site Michael
Harte 01892 78329 firstname.lastname@example.org
Geoff Rathbone 01959 524727
Any material for inclusion in the May Newsletter should be with the Editor by April 28th 2005
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