Part 1 - Early Days


The Charterhouse Centre Observatory was built in 1973 as a joint project between
Somerset Education Department and a local group known as the Mendip Astronomers.
Dr Philip Armitage from County Hall had been keen to establish an astronomy facility
at Charterhouse and called on the Mendip Astronomers to provide the expertise.
An approach was made to the well-known telescope manufacturer Dudley Fuller, who had
recently acquired Broadhurst Clarkson & Co.  Agreement was reached to purchase a
custom-made 18.25 inch Fullerscope Newtonian reflector.
Very little history is known about the construction of the dome, other than the fact that
it was designed by the Mendip Astronomers and a number of their members turned-up
at Charterhouse one snowy winter's morning to dig the footings !
The observatory was finished sometime in late 1973 and the grand opening included
 a number of high-profile visitors from County.  We have been told that the late
 Sir Patrick Moore attended the event, along with Dudley Fuller, but have been
unable to confirm this so far.
The new observatory was featured in a full page advert for Fullerscopes in the 1975
British Astronomical Association handbook and it included a photograph of Rob Miller 
who had designed the telescope's equatorial mount.  Rob Miller went on to establish
Catamount Systems in Colorado, a company that specialises in the design of equatorial
mounts for large telescopes.
While Mr Fuller was using the observatory to advertise his business, Somerset were busy
establishing it as the "Somerset Schools Observatory" and cheekily modifying the
Fullerscopes logo for their own purpose !
One of the first users of the telescope was a twelve year old boy called Nick James.
The grown-up Nick James attended one of our courses last year and he very kindly
copied the results of his early astro-photography experiments for us.
For several years, Somerset Education organised a Schools Astronomy Convention.
Four days of astronomy and accommodation for the rip-off price of 5.50 !
However, all was not well with the telescope.  By the beginning of 1978, Dr Armitage suspected a
problem with the primary mirror.  He sought the advice of Dr C R Burch from the University
 of Bristol's H H Wills Physics Laboratory.
Dr Burch undertook testing of the mirror and used two testing techniques - Scatter
Fringe and Knife Edge - to identify a serious astigmatism issue. 
He went on to recommend the use of a "strainer" to remove the error.  That's not as in
making a pot of tea, but rather a device in the form of a steel cross with fingers that
can gently push and pull the mirror to correct its shape !
The strainer in place at the rear of the optical tube assembly
Knife Edge test..........before Knife Edge test..........after
Results of the final Scatter Fringe test
Dr Burch's original notes from testing with the strainer
The strainer reduced the error by a factor of between 4 - 8 times, so overall a significant
improvement and Dr Burch received a personal letter of thanks from Barry Taylor, the
Chief Education Officer.
Very little is known about the work of the observatory in those early years.  A number of
the Mendip Astronomers became "approved users" and they visited the site on a monthly
basis, publishing the results of their observations in the Wells Journal.
The Mendip Astronomers group wound-up a few years later.  Combined with financial
pressures and changes of key staff at County Hall, the observatory fell into disuse at
the beginning of the 1980s - a situation that continued for over a decade !
We are extremely grateful to Hannah Lowrie from the Art & Social Sciences Library at Bristol
University for allowing us access to Dr Burch's archives DM1138/B39 - B40


Part 1 -  Early Days
Part 2 -  The 1990s
Part 3 -  The Millennium Dome
Part 4 -  Full Circle



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