Aerodist Station NM/C/40 :
Revisited in July 2015;
& August 2022


The Sturt Highway (National Route A20) runs for about 950 kilometres from Tarcutta in New South Wales to Gawler in South Australia.† The highway was proclaimed over existing roads in the 1930s.† It was named after Captain Charles Napier Sturt (1795-1869) who was an Australian colonial explorer and administrator.†

National Mapping Aerodist survey control station NM/C/40 is located on the north side of the Sturt Highway about 63 kilometres east of Hay in the Riverina district of New South Wales.† The station mark is beside the fence along the highway about 10-15 metres to the east of the entrance track to Gundaline station homestead.†

Gundaline station near the village of Carrathool comprises some 14,928 hectares of grazing and developed irrigation land including some 1,800 hectares of cotton plantings.† The property has a frontage to the Murrumbidgee River that runs to the north of the Sturt Highway in this area.† Ownership of the property is reported to have changed in recent years and it is currently held by the overseas backed Southern Agricultural Resources Limited.† The recent Gundaline station purchase settlement was reported to have been for around $25 million.

NM/C/40 is one of the some 480 survey control stations that were coordinated by Nat Mapís Aerodist airborne distance measuring system.† These stations formed networks that covered over 50 per cent of the Australian mainland and provided survey control for the 1:100,000 scale national topographic mapping program.† Some 29 Aerodist network blocks were established during field measuring operations that ran from 1963 to 1974.† NM/C/40 was in what finally became Aerodist Block 39; from the amalgamation of a number of earlier smaller blocks.

NM/C/40 was established in April 1966 and soon afterwards was occupied for Aerodist remote measuring operations by Nat Map Surveyor Rom Vassil with second-year Field Assistant John Ely.†

Rom Vassil revisited NM/C/40 in April 1969 with a ground marking and Tellurometer traversing field survey party.† The 1969 field party then comprised:

       Rom Vassil, Surveyor Class 1

       Norm Edwards, Surveyor Class 1

       Paul McCormack, Technical Officer Grade 1

       August Jenny, Technical Assistant Grade 2

       Oystein Berg, Field Assistant

       Blythe Osborne Field Assistant

       Eric Marques, Field Assistant (first year)

       Laurie McLean, Field Assistant (first year).

 

This field survey party departed Melbourne on 31 March 1969 with the following four wheel drive vehicles: Land Rover 109 inch wheelbase (ZSM 644); Forward Control Land Rovers (ZSM 656 and ZSM 658); and Bedford RLCH truck (ZSU 201).† The field survey party worked in the Hay area from the second to the seventh of April 1969 which included the Easter period that started on Good Friday 4 April 1969.†

The 1969 survey work in the Hay area included Tellurometer connections between NM/C/40 and New South Wales bench mark T81 (a thousand or so metres to the west) and between NM/C/40 and an eccentric mark that was established at NM/C/85 (about 4,400 metres to the east).† There were simultaneous astronomical observations for azimuth on the magnitude 5.42 star Sigma Octantis between NM/C/40 and T81 and between NM/C/40 and the eccentric mark at NM/C/ 85.† August Jenny did the survey observations at NM/C/40 and was pleased that the spread in his five rounds of Sigma Octantis azimuth observations was within 3.8 seconds of arc.† Simultaneous reciprocal vertical angles and second order horizontal angles were also observed.† A third order spirit level connection was made from T81 to NM/C/40, photo reference points were identified, and terrestrial photography was taken.

 

As shown on the National Mapping Council station summary below, NM/C/40 was occupied again in 1982 when observations for precise position were made on the then United States Navy Navigation Satellite System (TRANSIT) using a JMR Doppler satellite receiver.

 

Former Nat Mappers Lawrie OíConnor and Laurie McLean visited NM/C/40 on 19 July 2015.† They happened to be driving along the Sturt Highway when travelling on holiday between Gundagai and Balranald.† Laurie was able to recollect the station site from 1969 memory (NM/C/40-about 40 miles from Hay).† The 2015 images of NM/C/40 below were taken during that brief stopover.

 

As shown in the images below, on the 2015 revisit the southern two witness posts were missing and a star picket marker had been added.† The station mark was covered by soil and grass as indicated by the reduced height of the witness posts protruding above ground level.† The station mark had to be dug around with a spade and brushed over with a bannister brush before it could be photographed.† It was otherwise in excellent condition.† The 2015 visitors did not have a station summary and so did not search for the recovery marks which were not sighted.

 

Location of NM/C/40 on Google Earth image (annotations by Paul Wise)

 

Nat Map Aerodist block diagram showing NM/C/40 (annotated by Paul Wise)

 

Surveyor Rom Vassil operating an Aerodist remote unit at NM/C/40 in April 1966 (Nat Map image)

 

Nat Mapper Lawrie OíConnor at NM/C/40 in July 2015 (Laurie McLean image)

 

NM/C/40 station mark in July 2015 (Laurie McLean image)

 

Nat Mapper Lawrie OíConnor at NM/C/40 in July 2015 (Laurie McLean image)

 

NM/C/40 in August 2022 (David Nash image)

 

National Mapping Council station summary for NM/C/40

 

 

This article was prepared by Laurie McLean in October 2015 following consultations with Paul Wise, Rom Vassil and August Jenny. Photograph courtesy David Nash added 2022.