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Southern Skies
by: Eric J. Brown |
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A Brief History Of Australian Astronomy and The Sydney Observatory
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The Australian sky is different from the sky seen by people in Europe,
North America and Asia. Many wonderful sights such as the Southern Cross
and the Magellanic Clouds are unique to the southern sky. |
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The front gate and some of the gardens leading up to the
observatory. |
Australian Astronomy
Astronomy has played an important role in the history of New South Wales;
in fact, the voyage of Captain James Cook in the "Endeavour" had, as its
prime objective, the observation of the transit of the planet Venus across
the sun from Tahiti. This observation, combined with others, made in northern
latitudes, gave an improved value of the distance of the sun.
Then, in 1788, Lieutenant Dawes set up a small observatory on what
is now called Dawes Point at the foot of the present day Observatory Hill.
His instructions were to observe a comet predicted by the famous astronomer,
Edmund Halley, to return about 1790. Dawes did not observe the comet, but
neither did astronomers in the northern hemisphere, where it was predicted
to be more prominent.
Governor Sir Thomas Brisbane arrived in 1821 bringing with him two astronomers,
Charles Rumker and James Dunlop. Brisbane set up a small observatory at
Parramatta at his own expense. Work done here included an important catalogue
of stars, observations of comets, nebulae, double stars and observations
for latitude and longitude. The observatory was sold to the government
in 1825 when Brisbane left but the work continued under Dunlop until 1847.
Due to ill health Dunlop resigned and the observatory was closed.
The establishment of a new observatory was soon being discussed. One
reason for this was to provide a time service for shipping by dropping
a time ball. Thus an important criterion for choice of site was that the
time ball should be visible to ships in the harbour. Sir William Denison,
who was appointed Governor in 1855, took a keen interest in this idea and
urged that the new observatory should have activities beyond the work of
the time ball. He was anxious that it should "connect this colony with
the scientific societies of Europe and America."
In 1856, the first Government Astronomer, William Scott, was appointed
and the building of the observatory was commenced. The observatory, built
with Sydney sandstone and designed in the style of the Florentine Renaissance,
was completed in 1858. The first two astronomers, William Scott and George
Robarts Smally had relatively short tenures; 1858-1862 and 1864-1870 respectively.
During this period, besides the time service, the observatory was responsible
fir the recording of the weather and a wide network of meteor logical observers
were setup throughout New South Wales. Work was done on recording magnetism
and tides in both Sydney and Newcastle harbours.
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Photoheliograph were used to take pictures of the sun. These instruments
are telescopes that can cope with the sun's intense heat.
This one was made in London and purchased by the Sydney Observatory
for the 1874 transit of Venus. During the transit, it was used at the Woodfords
Observatory's station in the Blue Mountains. |
In 1870 Henry Chamberlain Russell was appointed and worked as Government
Astronomer until illness forced his retirement in 1905. By late 1874 Russell
had already started to observe double stars with the new 11" equatorial
refractor and a meridian program with the transit instrument.
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Visible at the top of the observatory is the time ball. Every day at
exactly 1 p.m., the time ball on top of the tower would drop to signal
the correct time to the city and harbour below. |
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In 1877, a western wing was added to provide office and library space
and a second domed chamber for extra telescopes. |
Towards the end of this period, a seismograph for recording earth quakes
was installed. In 1887 Russell was invited to a conference in Paris on
stellar photography. This conference decided to compile, by photograph,
a great catalogue of stars over the whole sky to reach magnitude. 11. This
became known as the astrographic catalogue. Russell undertook two zones
of the sky on behalf of Sydney and Melbourne observatories. The astrographic
telescope was acquired and arrived in 1891. Russell hoped to move the astrograph
out of the city and a site was obtained at Pennant Hills, but because of
financial constraints, the move did not take place until 1899. At that
time work was also commenced on observing the reference stars which are
required for each photographic plate.
In 1903 Russell became ill and retired in 1905. Russell was replaced
by Henry Alfred Lenehan in 1903 and after Russell died Lenehan was appointed
Successor. In 1903 Lenehan co-operated with Otto Klotz of the Dominion
Observatory, Ottawa, to measure longitudes across the Pacific. This operation
closed the circuit of longitudes around the world for the first time. In
1907 the meteorological services were taken over by the Common Government
while the astronomical observatories remained under control of the states.
Lenehan died in 1908 and his successor, William Ernest Cooke, was not
appointed until 1912. Cooke felt some doubt about the value of the photography
done before his time and referred his doubts to the Astronomer Royal, Sir
Frank Dyson, who, wisely, advised him not to begin again after so many
years of work, bit to go ahead with some publication. By 1925 the first
six volumes were published.
In 1926 a decision was made to close the observatory but as a result
of protests this decision was reversed although staff was heavily reduced.
Cooke retired in 1926 and James Nangle was appointed as successor. The
work on the astrographic catalogue continued and by 1940 seventeen volumes
had been published. Nangle died in February 1941.
Harley Wood, who had been at the observatory since 1936 as an assistant,
was appointed astronomer in 1943. Additional staff were appointed and more
rapid progress was made on the catalogue so that by 1955 all the measures
were complete although the final volume was not published until 1963. An
additional volume, number 53, containing an explanation of the whole work,
was issued in 1971.
In 1975 Harley Wood retired and was replaced by William Humphrey Robertson.
After completion of the catalogue, several new areas of observation were
undertaken. Advantage was taken of old plates to provide early measures
to determine the motions of stars by comparing them with plates taken in
recent years. Most emphasis in this work was given to motions of variable
stars and of the stars in the areas containing galactic clusters. Observations
were made of minor planets, especially those which come well south of the
Equator and so could be less well seen from northern observatories.
Sydney Observatory has done mush work for education in astronomy. For
many years adult education classes were taken by Wood or Robertson fir
the Department Tutorial Classes of the University of Sydney and also for
many years on several evenings of each week parties of public visitors
have been conducted around the Observatory to be shown through the telescope
on fine nights or given an illustrated lecture if the evening proved dull.
 The
observatory gardens were extended to the existing fence lines about 1875.
Formal gardens were cultivated, but these lost their elegance during the
20th century. For some times a tennis court
was the main feature of the front lawn. In 1987 the grounds were landscaped
to recreate the layout and vegetation of the 1880's. |
In June of 1982 came the announcement that the observatory would be
closed. At that time it became part or the Powerhouse Museum under the
wing of the Ministry of the Applied Arts and Sciences. The Observatory
contributes to education in astronomy by public visits during the day and
evening viewing sessions. The Observatory assists amateur astronomical
societies and staff members give courses of popular lectures through the
Workers' Education Association.
The Telescope
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This is a view of the 11 inch refractor. This historic lens telescope
in the south dome dates from 1847 and is the oldest regularly used telescope
in Australia. |
The historic lens telescope (an 11" refractor) in the south dome dates
from 1847 and is the oldest regularly used telescope in Australia. The
telescope drive system was run on a lead weight on a cable that ran from
the tower down to the basement. The length of the run was about 40 feet.
This would work to drive the scope for 45 minutes and was accurate enough
for 10 minute photography. The telescope was used for some spectroscopy
but very little. It was one of the first scopes used to photograph the
southern sky.
In 1877 the scope was put on the present mount. Before that a wooden
mount was used (1867). In the 1860's the lens weren't achromatic. The flaws
in the lens would show up with discoloration around bright stars (sirius)
and planets (venus). This was later corrected. The original lens was made
by Hugo Schroaded of Germany.
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Mounting and drive system of the telescope. |
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View of the eyepiece, focuser and finder scope. |
In contrast the mirror (14" Schmidt-Cassegrain) in north dome is fully
computer controlled and uses "The Sky" software. This is used for
public star nights.
The
observatory gardens were extended to the existing fence lines about 1875.
Formal gardens were cultivated, but these lost their elegance during the
20th century. For some times a tennis court
was the main feature of the front lawn. In 1987 the grounds were landscaped
to recreate the layout and vegetation of the 1880's.
