|Patent Application for the Dixon Ultra Wide Angle Lens|
US Pat. Nº 3068752
image by U.S. Patent Office (Image rights)
The Weapons Research Establishment Target Aircraft Recorder (WRETAR) is one of a suite of specialised cameras developed in the mid- to late 1950s by the Weapons Research Establishment (South Australia) in conjunction with the Anglo-British guided weapons development. The WRETAR is as a more compact and light weight alternative to the Dekko GW 1 and Beck GW 2 target aircraft cameras. While technically a high speed cine camera, shooting at 100 frames/second, the resulting negatives were not projected as a film but examined individually in order to assess the miss distance of the missile in relation to its target.
In 1955-56, the Australian Government Aircraft Factories (GAF), in collaboration with Australia’s Weapon Research Establishment (WRE), developed a newly designed ultra-wide lens with 210º coverage. When fitted to a newly designed 35mm film camera capable of 100 frames / second (WRETAR), the lens yielded a coverage of 186º. Thus one unit could cover a full hemisphere. The smaller lens allowed for much more compact design of the wingtip camera recorders, reducing the number of cameras required in each pod from 5 to 2 and thus reducing overall weight by 70lb. The camera was ready for prototype production in March 1956. Two design options had been developed for the camera, a short back-focus version and a more slender long back-focus one. The first option was the preferred version and entered service in 1957. The whole sky could be covered with two units in the standard wing-pod configuration, with one camera mounted looking up and the other one looking down. This required only small blisters to protrude from the pods. WRETAR was capable of ‘recognising’ a missile within 250ft of the camera (larger missiles at a greater distance). 
The film magazine took a standard 50ft roll of 35mm cine film, which gave the camera a run time of 12 seconds.. Variant models of the camera used 100 foot daylight loadable rolls of 35mm film on a thinner base, which allowed for 24 seconds run time (or to record two trials at 12 sec each).
A number of WRETAR versions were produced with varied advance speeds, exposure times and apertures:
- WRETAR Mk 1 is capable of 100 frames /second at 1 milli-second exposure with an aperture of F/8 (when fitted with a minus bluefilter). A roll of 35mm film gives a maximum running time of 20 seconds.
- WRETAR Mk 2 Listed but no details known. Additional versions with altered advance speeds (up to 160 frames/second,had been developed.
- WRETAR Mk 3 Listed but no details known.
- Dixon, F.A. (1961) Cameras with Wide Fields of view used in Rocket Research at the Woomera Range, South Australia. In: K.J. Habell (ed.), Proceedings of the Conference on Optical Instruments and Techniques London 1961. New York: John Wiley & Sons. Pp.273-278.—‘Wide Angle Lens Systems.’ US Patent Filed 23 Dec 1957; Issued 18 Dec 1962. Applicants: Robert P. Bonnell, Jack V. Ramsey and Robert A Dillon, assigned to The Commonwealth of Australia. US Pat. Nº 3068752.—This was a major development for the Australian optics industry: Steel, W. H. (1964) Optics in Australia. Applied Optics vol. 3, nº 7, pp. 839-842.
- A.M.P.O.R. for Target Aircraft. Memorandum N.W.Hodgson, Manager GAF, Fishermen's Bend, to Controller WRE, Salisbury. Dated 3 November 1955. Contained in File: "Incorporation of Modifications AMPOR Cameras Mk 1A.' Australian Archives A705 File 165/2/80.
- Proposed improved AMPOR Instrumentation System. R.P. Bonnell, P.O. Optics and Servomechanisms to Superintendent Techniques, dated 19 March 1956 file nº SA 5270/2 SOA 117. Contained in File: "Incorporation of Modifications AMPOR Cameras Mk 1A.' Australian Archives A705 File 165/2/809.
- The first production run was 192 units (DSTO Timeline 1946 - 2007).—In the U.K. the WRETAR was called WRE Mk. 1
- Evans, J.B. (1963) Analysis of records obtained from target aircraft camera systems. Royal Aircraft Establishment Technical Note IR 32, November 1963. London: Royal Aircraft Establishment (Farnborough), Ministry of Supply (UK National Archives AVIA 6/25551).
- Frost, J.M.R. & Morton, P. (1988) Instrumentation at the Woomera Rocket Range. Australian Journal of Instrumentation and Control vol. 3 nº 3, pp. 18-20.
- Wood, J. (1962) Wide Angle Lens Instrumentation. Missile. Quarterly Magazine for the Members of the Weapons Research Establishment Institute vol. 8 nº 1, pp. 4-6,
- Royal Aircraft Establishment (1968) Air Targets at the R.A.E. Aberporth Range. Air Targets Issue 3, November 1968. AVIA 6/23916. Royal Aircraft Establishment (Ranges Division).
- Anon (1963) This is Fairey: Fairey Aviation Company of Australasia Pty Ltd. Fairey Review, vol. 5 nº 3, p. 39-43.
- Smith, A. T. (1973) Miss Distance Measurement Using One Camera. Royal Aircraft Establishment Technical Report 73162 (9 October 1973). London: Royal Aircraft Establishment (Farnborough), Ministry of Defence.