How Was Edmond Halley’s Map of Magnetic Declination (1701) Constructed?

Murray, Lori L.; Bellhouse, David R.

doi:10.1080/03085694.2017.1242841

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…Curiosity about the Earth's field and how it changes in time prompted measurements of declination in London from the sixteenth century onward (Barraclough et al., 2000; Malin et al., 1981). In the late seventeenth century, Edmund Halley led several voyages to produce maps of declination across wider areas of the Atlantic Ocean primarily for the purpose of longitude determination; though he later realized that secular variation (SV) significantly reduced the accuracy of his maps after a few years (Murray & Bellhouse, 2017). In 1832, Gauss developed a method for measuring total field intensity (Garland, 1979; Glassmeier & Tsurutani, 2014) which launched an international “magnetic crusade” to make high‐quality measurements around the world (Collier, 2014).…”

Section: Introductionmentioning

confidence: 99%

Digitized Continuous Magnetic Recordings for the August/September 1859 Storms From London, UK

Beggan,

Clarke,

Lawrence

et al. 2024

Space Weather

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Dedicated scientific measurements of the strength and direction of the Earth's magnetic field began at Greenwich and Kew observatories in London, United Kingdom, in the middle of the nineteenth century. Using advanced techniques for the time, collimated light was focussed onto mirrors mounted on free‐swinging magnetized needles which reflected onto photographic paper, allowing continuous analog magnetograms to be recorded. By good fortune, both observatories were in full operation during the so‐called Carrington storm in early September 1859 and its precursor storm in late August 1859. Based on digital images of the magnetograms and information from the observatory yearbooks and scientific papers, it is possible to scale the measurements to International System of Units (SI units) and extract quasi‐minute cadence spot values. However, due to the magnitude of the storms, the periods of the greatest magnetic field variation were lost as the traces moved off‐page. We present the most complete digitized magnetic records to date of the 10‐day period from 25 August to 5 September 1859 encompassing the Carrington storm and its lesser recognized precursor on 28 August. We demonstrate the good correlation between observatories and estimate the instantaneous rate of change of the magnetic field.

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Section: Introductionmentioning

confidence: 99%

Digitized Continuous Magnetic Recordings for the August/September 1859 Storms From London, UK

Beggan,

Clarke,

Lawrence

et al. 2024

Space Weather

View full text Add to dashboard Cite

show abstract

“…Curiosity about the Earth's field and how it changes in time prompted measurements of declination in London from the sixteenth century onward (Barraclough et al, 2000;Malin et al, 1981). In the late seventeenth century, Edmund Halley led several voyages to produce maps of declination across wider areas of the Atlantic Ocean primarily for the purpose of longitude determination; though he later realized that secular variation (SV) significantly reduced the accuracy of his maps after a few years (Murray & Bellhouse, 2017). In 1832, Gauss developed a method for measuring total field…”

mentioning

confidence: 99%

Digitized continuous magnetic recordings for the August/September 1859 storms from London, UK

Beggan,

Clarke,

Lawrence

et al. 2024

Preprint

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Dedicated scientific measurements of the strength and direction of the Earth's magnetic field began at Greenwich and Kew observatories in London, UK, in the middle of the 19th century. Using advanced techniques for the time, collimated light was focussed onto mirrors mounted on free-swinging magnetized needles which reflected onto photographic paper, allowing continuous analogue magnetograms to be recorded. By good fortune, both observatories were in full operation during the so-called Carrington storm in early September 1859 and its precursor storm in late August 1859. Based on digital images of the magnetograms and information from the observatory yearbooks and scientific papers, it is possible to scale the measurements to SI units and extract quasi-minute cadence spot values. However, due to the magnitude of the storms, the periods of the greatest magnetic field variation were lost as the traces moved off-page. We present the most complete digitized magnetic records to date of the ten-day period from 25th August to 5th September 1859 encompassing the Carrington storm and its lesser recognised precursor on the 28th August. We demonstrate the good correlation between observatories and estimate the instantaneous rate of change of the magnetic field.

show abstract

European constellation development

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2019

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How Was Edmond Halley’s Map of Magnetic Declination (1701) Constructed?

Cited by 6 publications

References 2 publications

Digitized Continuous Magnetic Recordings for the August/September 1859 Storms From London, UK

Digitized Continuous Magnetic Recordings for the August/September 1859 Storms From London, UK

Digitized continuous magnetic recordings for the August/September 1859 storms from London, UK

European constellation development

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