Sydney Observatory Papers No.31

Part 7



William Ernest Cooke was born on 1863, July 25, in Adelaide. After graduating from Adelaide University he was attached to Adelaide Observatory. When Perth Observatory was founded in 1896 he was appointed first director and was successful in developing the work on the Astrographic Catalogue. In 1912 he was appointed Government Astronomer for New South Wales and Professor of Astronomy at the University of Sydney.

Cooke was offered the opportunity to reorganise the work of the Observatory and to move to a better position. A site selected by T. W. E. David, James Nangle and Cooke, was acquired about half a mile east of Wahroonga Railway station. [pg. 20]

This was regarded as being far enough out of the city to avoid the worst effects of haze and light in the sky but close enough to make University and public contacts reasonably possible. Among the pieces of equipment planned for the reconstructed Observatory were a mirror transit to make possible observation of fainter stars and a reflecting telescope of an aperture about twenty four inches. He planned to begin fundamental transit work as recommended by the meeting of the Commite International permanent pour lExecution de laCarte photographique du Ciel in 1909. Cooke devoted much energy to all this planning but the 1914-18 War caused it to be postponed indefinitely in 1916 and despite all his efforts he was unable to revive it. Several attempts failed, too, to bring about his projected tour of inspection of observatories in Europe and America.

As a preliminary it was necessary to assess the twenty years work already done on the Astrographic Catalogue. Before he arrived Cooke asked Raymond to prepare a list of positions of stars with meridian observations and found that, contrary to his previous impression, there were not enough positions of reference stars available reduction of the photographic plates of the Catalogue. He decided to reorganise the transit work by observing strictly in accordance with the recommendations made at the 1909 meeting of the Comite' permanent de la Carte du Ciel. According to this plan the lists of stars were to be observed strictly differentially relative to selected stars for which fundamental observations were obtained. His methods of observing and of reducing the observations, described two papers in Monthly Notices of the Royal Astronomical Society and in the Catalogue of 1068 Intermediate Stars enabled the output to be much increased and the reductions to be kept right up to date. The first observations of the programme began in March, 1918, on the intermediate stars of our astrographic zone −51° to −65°. By June, 1921, this work was complete including discussion of pivot errors, circle errors and personal equations, and the Catalogue of 1068 Immediate Stars was printed and distributed in 1922. Work was immediately begun on the reference stars for the reduction of the plates of Astrographic Catalogue. These observations were made in zones two degrees wide differentially relative to theintermediate stars. The zone from −51°to −57° was finished in catalogue form by March, 1922, and that for −53° to −55° in 1923. These two catalogues have not been published.

The difficulty of making meridian observations of the faint stars which had to be observed in order to yield enough reference start for the astrographic work led Cooke to develop ideas for obtaining a large aperture by designing a mirror transit but he is-as unable to obtain resources to have it made.

In 1922, when Schlesinger, of Yale University Observatory, received the Catalogue of 1068 Stars he wrote to Cooke to suggest the other southern zones might be observed in the same way. He was engaged in the determination of star places using photographs in wide angle and said that he hoped to use intermediate stars as the basis. Cooke undertook to observe the zone −30° to −51° thus links up with work reaching to −30°, which was being done at the United States Naval Observatory. The observations were made in I923 and 1924 but the catalogue was published on only in 1949 as Sydney Observatory Papers, No. 8 Out of the correspondence Schlesinger arose the suggestion that the plates of the southern zone corresponding to our astrographic section should be measured at Sydney. The difficulty of obtaining a sufficient number of suitable reference stars for the Catalogue would be this solved. This was agreed and Cooke set about equipping himself with rather formidable measuring machine required to measure plates of dimensions nineteen inches by twenty three inches. Cookes term of ended before this scheme bore anyfruit. [pg. 21]

In December, 1914, Cooke asked for the appointment of a Board of Visitors to the Observatory to take a general oversight and interest in its work and to offer advice to the Government on matters affecting the Observatory. The previous Observatory Board of Russell's time had, according to Lenehan lapsed because of lack of a quorum for meetings. Cooke's recommendation was approved and the Board first met on 1916, August 16. Subsequent experience has shown the Board of Visitors to be a valuable adjunct to the 0bservatory. At the first meeting of the Board Cooke expressed doubt as to the value of much of the photographic work already done for the astrographic Catalogue because he thought that variation of procedures which had occurred since the beginning would stand in the way of using the material to determine magnitudes or the distribution of the stars according to magnitude. Actually the needs of this work are different from what they appeared to be when the astrographic programme was designed and the astrographic material is not suitable for determining magnitudes. Cooke did, however, recognise that the plates were valuable for study of stellar motions and later, using plates of epoch difference ten years or more, co-operated in this work with Innes, Director of the Union Observatory. When, at the Boards request, Cooke referred his doubts to the Astronomer Royal Dyson's recommendation was to prepare for publication the measures already made. This Cooke proceeded to do with commendable energy. The Board also recommended, that, if the move to Wahroonga was not to take place, arrangements should be made for the Government Astronomer to reside at the Observatory. The Weather Bureau moved out of the residence which it had occupied since the separation in 1908 and Cooke, in his report of 1917, commented on the value of his residence on the spot for his Observatory work and for the practical classes with his University students.

Soon after his appointment Cooke had decided that he preferred to make measurements of the astrographic plates at Sydney and ordered a machine for measuring rectangular co-ordinates of the stars on the plates. The Turner pattern arrived in 1915 and he had some and has some clerical staff appointed to make measures and to assist in preparing the manuscript of the Catalogue. Another machine was later added and the measurement was accelerated. He made some improvements to the astrograph, standardised the exposures and the processing of the plates and, as a check on the transparency of the atmosphere, began regular photography of the area around the south celestial pole along with the plates for the Catalogue. For magnitude purposes he arranged a graduated series of star images in the eyepiece of each measuring machine with which the image of each star was was compared as it was being measured. The magnitude values of these scales were determined by photographic of the standard areas (E regions) at declination at -45°. By 1925, despite several postponements while he was obtaining finds, there were six volumes of the Catalogue published. The installation of the apparatus for the work and the publication of these first results thus determined the form since followed for the Sydney Section of the Astrographic Catalogue.

Cooke was very much interested in time signals and longitude determination, on which he published several papers. By February, 1913, he was suggesting that accurate time should be made available to telephone subscribers by connecting a clock in the Observatory to a sounder which could be connected to the telephone system. This service to telephone subscribers was arranged in 1914 and remained inthe same form until 1954. The introduction of the wireless time signals for navigation which he suggested at the same time did not occur until 1924.

For want of financial support Cooke was compelled to drop an extensive plan to determine longitudes in the Pacific in 1916 but the subject arose again in connection with the fixing of the boundary between South Australia and Western Australia [pg. 22] on the 129th meridian, when it was hoped by an accurate determination to avoid kind of difficulties that had earlier led to the expensive litigation about the boundary between Victoria and South Australia. With the co-operation of the Astronomers Royal of England and Scotland and of General Ferrie' Director of French Radio System, and others, a series of experiments was conducted to find time transmissions which could be heard in both Greenwich and Sydney. The signals from Lyons proving most suitable a series of observations in co-operation with the French and English authorities in 1921, April and May, gave the longitude of Sydney 10h 4m 48.98′ east of Greenwich. Cooke continued his experiments on reception of wireless time signals even after this programme was complete since he thought that the views of astronomers here important because of the long paths the signals had to follow to reach this part of the world.

The total solar eclipse of 1922, September 21, aroused a great deal of interest among Australian astronomers, both professional and amateur, and brought observing expeditions here from abroad. With the support of the Board of Visitors Cooke obtained approval to move the astrograph to Goondiwindi in Queensland. Bad atmospheric definition and poor performance of the driving clock of the telescope led to failure of an attempt to measure the deflection of starlight passing near the Sun for comparison with the value predicted by Einsteins Theory of Relativity but the times of the contacts were observed, both by eye and by measurement of a series of timed photographs, and at Grafton the southern edge of the Moons shadow was fixed by a line of observers.

Of several minor activities his interest in sundials seems most important. He published original designs for home construction and in 1924 patented an improvements intended for commercial production which would undoubtedly have been success but for the introduction of radio time signals.

At Sydney University, Cooke, from 1914 onwards, gave a course for second year students with a gradually increasing, though never large, of students. He also carried on adult education classes for the Department of Tutorial Classes of the University, including several lecturer tours of country centres. His students remember him with respect and attention. This valuable association with the University terminated with Cookes retirement.

In October, 1925, a very strong recommendation by Cooke in favour of the move to Wahroonga was brought before the State Cabinet who at first decided that they would close the Observatory, rather than bear the expense of moving and re-equipping it but representations by the Board of Visitors of the Observatory, the Royal Society of New South Wales, the New South Wales Branch of the BritishAstronomical Association and Sydney University caused to modify this decision and agree at first to continue only the time service but later, on a much reduced scale, the work of the Astrographic Catalogue, an international obligation. Cooke, who was close to the retiring age, left the Observatory on 1926, August 31, and most of the staff of the Observatory was transferred to other Departments.

Those people who had best opportunity to know Cooke respected him as a man and as an Astronomer but he did not always work well within the restrictions of the Public Service and felt frustrated by the failure to carry out the reorganisation he had expected when he came. W. E. Raymond and H. C. Cranney who were engaged on the transit programme, undertaken during the second part of his period here put forth tremendous efforts which speak unmistakable for the inspiration he was able to give them. After his retirement Cooke returned to Adelaide to lived and died there on 1947, November 7 [pg. 23]


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