Mills Cross Radio Telescope Construction

Observations of the Heavens

A statement released by the Chatterton Astronomy Department within the School of Physics and the School of Electrical Engineering announcing "The new Radio Astronomy Centre of the University of Sydney" noted that, "Radio astronomy is concerned with observations of the heavens at radio wavelengths rather than with light waves. It is a relatively new and vigorously growing branch of one of the oldest of the sciences, and Australia has taken a leading part in its development. Almost all of the Australian work, so far, has been carried out by the radio astronomy group in the Radiophysics Division of C.S.I.R.O. Recently, however, several members of this group have joined the staff of the University...One group, led by Dr. B. Y. Mills [Bernard Yarnton Mills], who was previously with  C.S.I.R.O., will engage immediately in radio astronomy work...Radio astronomy, however, is the meeting point of astronomy, physics and all the most advanced techniques of electronics and electrical engineering...The Centre will mean the pooling of resources, intellectual and material of the Schools of Physics and Electrical Engineering for an attack on some of the major fundamental problems of radio astronomy...One of the first problems to be considered by the Radio Astronomy Centre is that on which Dr. Mills has been engaged for some years; the detailed observations of sources of radio emission both in our own galaxy and in the very distant regions of space...perhaps help to answer the age-old question as to its origin. For the new studies a very large radio telescope will be needed, far too large to be built in a completely steerable form, such as the large paraboloid being constructed by the C.S.I.R.O. at Parkes. The radio telescope needed for this work must have dimensions of about one mile and the most suitable form for this is a cross-like structure invented by Dr. Mills and called a Mills Cross. The cost of a radio telescope of this type and size will be about £300,000. The Chatterton Astronomy Department supported by the Nuclear Research Foundation has set aside £100,000 for the first stage of this telescope. The rest of the cost to complete the instrument to its full size must be raised elsewhere".

Dr Mills reached out to possible donors both within and outside of Australia. In one letter to Dr GF Mulders of the National Science Foundation (NSF) in Washington DC, dated 2 February 1961, Dr Mills wrote, "The instrument will be almost [underlined] unique! It is known that a similar Cross has now been completed in the U.S.S.R., but our information is that the resolution and general flexibility is considerably less. Another instrument...is under consideration in Holland. As far as I know ours is the only instrument of this type in which spectral information will be obtained by simultaneous observation on two frequencies...Finally, and most important, is the location in the southern hemisphere...In order to study the central and southern regions of the Galaxy and the Magellanic Clouds...it is essential to have such an instrument in the southern hemisphere". By this point, however, it appears the estimated cost of the Mills Cross Telescope had more than doubled since the Radio Astronomy Centre statement, "The estimated cost of our radio telescope is about £660,000, of which £220,000 is currently available. This is for the minimum amount of complexity...There appears little prospect of raising the additional sum from governmental contribution in Australia and it seems we must obtain support overseas if the instrument is to have a size and flexibility commensurate with the observational problems to be tackled".

On 7 December 1961, Dr Mills wrote to the Australian National University with an update, which indicated that a funding proposal was formally submitted to the National Science Foundation and that the, "...grant was in fact approved by the National Science Board last October and I have been led to believe that the delay in finalizing the grant and the reason for Dr. Keller's [Program Director for Astronomy at the NSF] present visit may be connected with some objections from C.S.I.R.O., principally on the basis that the magnitude of the project has been underestimated and our facilities are inadequate. I expect that we will be able to demonstrate to Dr. Keller that this is not the case, particularly in view of the very stimulating support of our development work by local industry in making available their experience and manufacturing facilities at nominal, and sometimes zero, cost". The Vice-Chancellor in another letter to the Australian National University, dated 8 December 1961, noted that the grant amount was $746,000 [US dollars]. The grant was eventually finalised in 1962 albeit with delays, which prompted Professor Harry Messel to send a telegram on 16 February 1962, "Mills project and group now seriously held up stop please notify when we can expect approval your end".

Although the promised National Science Foundation funds were received, the project continued to be plagued with financial problems, even as Dr Mills could report to the NSF, on 4 May 1965, "You will probably be pleased to hear that we are at last fully operational with the E-W arm of our Cross...At present several people are busy analyzing results with a view to some early publications, which, I think, would be a good thing politically. We are running into some troubles because of the failure of your financial people to forward cash advances as requested. I wonder if you might investigate and try and lubricate the wheels a little". The Mills Cross Telescope housed at the Molonglo Radio Observatory was opened in November 1965, however, the project still faced an "uncertain future" as on 20 October 1967, the NSF informed Dr Mills that, "Although until very recently I had hoped we could continue for one more year the support of your operation, this now appears to be very doubtful. Therefore, I am urging you to start looking for local sources of money to continue your work with the Mills Cross. I regret to have to tell you this, with so little notice, but at least I had given you some advance warning that the ax might fall one of these days". Dr Mills responded on 30 October 1967 declaring the news as, "...rather a shattering blow to our project". Dr Mills provided "some calculations" and noted that, "It is perhaps rather ludicrous that the future of such an expensive project should be threatened by the lack of such a small sum...I hope that you will not find it necessary to drop us entirely". It seems the NSF did not after all "drop us entirely" and enabled the University to successfully continue operating the Telescope and Observatory, as Dr Mills wrote to the NSF on 11 August 1980, "Nearly twenty years ago the National Science Foundation funded the construction of our Molonglo Radio Telescope and, although we are now supported entirely by local sources, it is evident that the project could not have begun without the NSF grants...Observations have ceased at 408 MHz and the radio telescope is currently being upgraded for use at a higher frequency and in a synthesis mode". Enter the Molonglo Observatory Synthesis Telescope (MOST). [Ref 1].

This item is part of the University Archives' 70 Years, 70 Stories series, created to celebrate our 70th birthday on 3 May 2024. To discover more stories, explore the 70 Years, 70 Stories collection.

Ref 1: Proposals, Reports, and Correspondence Related to the Mills Cross Radio Telescope (1960 to 1980), [REF-00088945]. University of Sydney Archives.