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In 1960 the University of
Pennsylvania received a grant from the U.S. National Science
Foundation to survey New Zealand to find the best site for an
astronomical observatory. Pennsylvania wanted to establish a
southern station and New Zealand was much further south than the
established observatories in Australia, South America and South
Africa. So from here more of the southern sky was continuously
visible throughout the year.
Comet passing through Mt John's night sky
© Alan Gilmore
Among the criteria for an observatory site were: a large number of
clear nights, a dark sky not polluted by artificial light from any
nearby town or city, a site reasonably close to power and water
supplies and main roads and not too far
from a major city.
The site survey began in 1961. It was organized by Mr Frank
Bateson, a New Zealand amateur astronomer internationally respected
as the Director of the Variable Star Section of the Royal
Astronomical Society of N.Z. From geographical and weather
information Bateson selected potential sites in the Bay of Plenty,
Nelson, Marlborough, the Mackenzie Country and Central Otago.
Between 1961 and 1963, with much help from local authorities and
individuals, various sites were occupied so sky conditions could be
continuously monitored.
By 1963 it was clear that Mt John
provided the best conditions, all things considered. The
University of Pennsylvania made an agreement with the University of
Canterbury to jointly develop the site, thus providing a city base
in Christchurch. The observatory was officially opened on 10
July 1965.
The observatory's early instruments were
astronomical cameras, provided by Pennsylvania, and telescopes lent
by Bateson. They were housed in buildings largely constructed
by volunteer labour from the South Canterbury district. In
1970 the 60cm (24inch) Optical Craftsmen (the 'OC') telescope was
installed.
Five years later a second 60cm telescope made by Boller and Chivens
(the 'B&C') was erected. During these years some of the
original University of Pennsylvania staff moved to the University of
Florida so it too became part of the consortium.
However, from about 1975
the contribution and interest of the U.S. partners waned as their
senior staff retired. The Observatory now operates entirely as
a field station of the
University of Canterbury's Department of Physics and
Astronomy.
Southern Cross and Pointers
© Alan Gilmore In 1969 the U.S. Air Force built a satellite
tracking station on Mt John south of the university observatory.
The USAF also funded the sealed road up the mountain and a water
supply from Lake Tekapo. Prior to this the Observatory had depended
on rainwater or tanker supplies brought up a rough track. The
tracking station employed a large staff for
following the positions of US and Soviet satellites.
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The USAF
tracking station closed in 1982 as new imaging technology made it
redundant and the building passed to the New Zealand
government. Canterbury University now leases the building and has
modified it, adding a large dome to the north end
to house its one-metre telescope. The 'One Metre building', as it is
generally called, accommodates visiting staff and observers. It also
houses an upper atmosphere experiment that measures wind and air
temperature 100 km above the ground, part of an international study. The One-Metre McLellan reflector was built in the University of
Canterbury’s workshops and was installed at Mt John in February
1986. It is used for a wide variety of astronomical research, most
of it in stellar astrophysics: the study of stars and their
evolution. In 2001 a large ‘fibre fed’ spectrograph made at
Canterbury was installed, greatly enhancing the telescope's
capabilities.
Since 1996 a consortium of New Zealand and Japanese researchers have
run a joint programme on the B&C telescope. It is called the MOA
project from Microlensing Observations in Astrophysics and involves
Auckland, Massey, Victoria and Canterbury universities on the NZ
side, and Nagoya University in Japan. Following a grant from the
Japanese government a 1.8-metre telescope was installed at Mt John
in 2004. It will continue the microlensing work, watching many
millions of stars for changes in brightness. In 2003 the MOA team
discovered a Jupiter-size planet orbiting a star several thousand
light-years away.
Orion Nebula
© Alan Gilmore
As services to the local community the Observatory hosts Vodaphone
cell-phone antennae and a FM repeater for National Radio.
On a pillar near the summit is a GPS station run by the Institute of
Geological and Nuclear Sciences and the Survey Department of Otago
University. It is the base station for measuring bending of the
South Island around the Alpine Fault.
A webcam gives hourly updates of the region's weather.
Earth & Sky, a Tekapo company, now runs daytime tours of the
Observatory. In 2005 they plan to install a 40-cm telescope for
public viewing in the '16-inch' dome.
Since Mt John was established, the village of Lake Tekapo has grown,
so increasing night sky brightness has become a concern. Mackenzie
District Council ordinances require that all outside lights be full
cut-off so that no light shines upward into the sky. The new
subdivision developers are installing observatory-friendly,
low-pressure sodium lighting.
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Special thanks to Air Safaris and Services for the
aerial photo of Mt John observatory. |
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