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(HP-65) Third-Order Magnetic Survey
06-15-2019, 12:01 PM
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(HP-65) Third-Order Magnetic Survey
An extract from Third-order Magnetic Survey of Yorke Peninsula SA, Bureau of Mineral Resources (Geology & Geophysics),Record 1982/10, February 1982 (19 pgs.)

SUMMARY
Third-order magnetic measurements of horizontal intensity, total intensity and declination were made at twenty-eight stations on Yorke Peninsula, in February 1981. This completes the coverage of South Australia and is a continuation of the third-order magnetic survey to chart features of the regional magnetic field having dimensions of 50-100 kilometres within Australia.
1. INTRODUCTION
… A third-order station is defined by map coordinates and the magnetic field is measured only once with an accuracy of 20 nT.

2. OPERATIONS
… Pre-survey instrument comparisons were carried out (Table 1) and the following instruments were used during the survey: Quartz Horizontal Magnetometer (QHM) serial number 306 (with QHM 288 carried as a backup) for the measurement of horizontal intensity (H)

3. RESULTS
…The map coordinates (to one tenth of a minute) and the elevation were entered on the observation forms and the results calculated using a Hewlett Packard 65 programmable hand calculator.
H was calculated using the program in Appendix 3. To check for errors in D, the sunshots were plotted on graph paper with time as the abscissa and the magnetic bearing of the sun as the ordinate. For the direct sightings a straight line was obtained and for the objective pentaprism sights two parallel lines.


APPENDIX 1
First-order station
Second-order station
Third-order station


APPENDIX 2
Observing Equipment


APPENDIX 3
HP-65 OHM Program - Card I

Temperature + Ø

HP-65 OM Program - Card 2
OHM 306


APPENDIX 4
Observations of the sun for Azimuth: BMR procedure


HP-65 PROGRAM
Observation of the sun for Azimuth


Ah, memories.

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