Offprints of articles relating to Geomagnetism from 1822 to 1981. Offprints collected by Kew Observatory, Meteorological Office, Edinburgh and Greenwich Observatory (Herstmonceux castle). The first page of each offprint has been digitised to produce a finding aid.

Magnetograms are records of variations in the strength and direction of the Earth’s magnetic field. Historically these magnetograms were recorded on paper using photographic techniques. In the UK, measurements were made at eight long-running observatories; Abinger, Eskdalemuir, Falmouth, Greenwich, Hartland, Kew, Lerwick, and Stonyhurst. BGS also hold magnetogram records from the Cape Evans observatory that ran continuously at Robert Falcon Scott’s Antarctic base camp during the British Antarctic Expedition 1910–13. The magnetogram collection, one of the longest running geomagnetic series in the world, provides a continuous record of more than 160 years of UK measurements. These magnetograms start in the 1840s and end in 1986 at which time digital recording of the magnetic field took over and magnetograms can be produced by computer graphic. The plots show variation in the Earth's magnetic field, typically over a 24-hour period. The collection is a valuable, partly untapped data resource for studying geomagnetic storms, space weather and the evolution of the Earth’s magnetic field. The magnetograms provide insight into: • the Earth’s outer core: long-term change (years to centuries) in the dynamo that sustains our magnetic field • space weather: short-term changes (seconds to days) in near-Earth space and on the ground • space climate: long-term change (decades to centuries) in solar activity and consequences for Earth’s environment All the above have an impact on human activities. For example, bad space weather affects technologies that we increasingly rely on, such as electrical power and GPS networks. In response to the threat of loss from degradation due to age and a desire to preserve and exploit old data, BGS undertook a programme of work to digitally photograph, archive and preserve the analogue paper records of magnetic field variation in the United Kingdom. Between 2009 and 2013, high-quality digital images of every available magnetogram were taken. These images are available to search online. Scientists and the general public around the world can now gain easy access to this historical dataset.

Magnetograms are records of variations in the strength and direction of the Earth’s magnetic field. Historically these magnetograms were recorded on paper using photographic techniques. In the UK, measurements were made at eight long-running observatories; Abinger, Eskdalemuir, Falmouth, Greenwich, Hartland, Kew, Lerwick, and Stonyhurst. BGS also hold magnetogram records from the Cape Evans observatory that ran continuously at Robert Falcon Scott’s Antarctic base camp during the British Antarctic Expedition 1910–13. The magnetogram collection, one of the longest running geomagnetic series in the world, provides a continuous record of more than 160 years of UK measurements. These magnetograms start in the 1840s and end in 1986 at which time digital recording of the magnetic field took over and magnetograms can be produced by computer graphic. The plots show variation in the Earth's magnetic field, typically over a 24-hour period. The collection is a valuable, partly untapped data resource for studying geomagnetic storms, space weather and the evolution of the Earth’s magnetic field. The magnetograms provide insight into: • the Earth’s outer core: long-term change (years to centuries) in the dynamo that sustains our magnetic field • space weather: short-term changes (seconds to days) in near-Earth space and on the ground • space climate: long-term change (decades to centuries) in solar activity and consequences for Earth’s environment All the above have an impact on human activities. For example, bad space weather affects technologies that we increasingly rely on, such as electrical power and GPS networks. In response to the threat of loss from degradation due to age and a desire to preserve and exploit old data, BGS undertook a programme of work to digitally photograph, archive and preserve the analogue paper records of magnetic field variation in the United Kingdom. Between 2009 and 2013, high-quality digital images of every available magnetogram were taken. These images are available to search online. Scientists and the general public around the world can now gain easy access to this historical dataset.

Magnetograms are records of variations in the strength and direction of the Earth’s magnetic field. Historically these magnetograms were recorded on paper using photographic techniques. In the UK, measurements were made at eight long-running observatories; Abinger, Eskdalemuir, Falmouth, Greenwich, Hartland, Kew, Lerwick, and Stonyhurst. BGS also hold magnetogram records from the Cape Evans observatory that ran continuously at Robert Falcon Scott’s Antarctic base camp during the British Antarctic Expedition 1910–13. The magnetogram collection, one of the longest running geomagnetic series in the world, provides a continuous record of more than 160 years of UK measurements. These magnetograms start in the 1840s and end in 1986 at which time digital recording of the magnetic field took over and magnetograms can be produced by computer graphic. The plots show variation in the Earth's magnetic field, typically over a 24-hour period. The collection is a valuable, partly untapped data resource for studying geomagnetic storms, space weather and the evolution of the Earth’s magnetic field. The magnetograms provide insight into: • the Earth’s outer core: long-term change (years to centuries) in the dynamo that sustains our magnetic field • space weather: short-term changes (seconds to days) in near-Earth space and on the ground • space climate: long-term change (decades to centuries) in solar activity and consequences for Earth’s environment All the above have an impact on human activities. For example, bad space weather affects technologies that we increasingly rely on, such as electrical power and GPS networks. In response to the threat of loss from degradation due to age and a desire to preserve and exploit old data, BGS undertook a programme of work to digitally photograph, archive and preserve the analogue paper records of magnetic field variation in the United Kingdom. Between 2009 and 2013, high-quality digital images of every available magnetogram were taken. These images are available to search online. Scientists and the general public around the world can now gain easy access to this historical dataset.

Magnetograms are records of variations in the strength and direction of the Earth’s magnetic field. Historically these magnetograms were recorded on paper using photographic techniques. In the UK, measurements were made at eight long-running observatories; Abinger, Eskdalemuir, Falmouth, Greenwich, Hartland, Kew, Lerwick, and Stonyhurst. BGS also hold magnetogram records from the Cape Evans observatory that ran continuously at Robert Falcon Scott’s Antarctic base camp during the British Antarctic Expedition 1910–13. The magnetogram collection, one of the longest running geomagnetic series in the world, provides a continuous record of more than 160 years of UK measurements. These magnetograms start in the 1840s and end in 1986 at which time digital recording of the magnetic field took over and magnetograms can be produced by computer graphic. The plots show variation in the Earth's magnetic field, typically over a 24-hour period. The collection is a valuable, partly untapped data resource for studying geomagnetic storms, space weather and the evolution of the Earth’s magnetic field. The magnetograms provide insight into: • the Earth’s outer core: long-term change (years to centuries) in the dynamo that sustains our magnetic field • space weather: short-term changes (seconds to days) in near-Earth space and on the ground • space climate: long-term change (decades to centuries) in solar activity and consequences for Earth’s environment All the above have an impact on human activities. For example, bad space weather affects technologies that we increasingly rely on, such as electrical power and GPS networks. In response to the threat of loss from degradation due to age and a desire to preserve and exploit old data, BGS undertook a programme of work to digitally photograph, archive and preserve the analogue paper records of magnetic field variation in the United Kingdom. Between 2009 and 2013, high-quality digital images of every available magnetogram were taken. These images are available to search online. Scientists and the general public around the world can now gain easy access to this historical dataset.

Annual means of the geomagnetic field vector components from observatories around the world, from 1840 to the present day. At present there are about 160 observatories. These data are useful for tracking changes in the magnetic field generated inside the Earth. Data are produced by a number of organisations around the world, including BGS. Data are available in plain text from www.geomag.bgs.ac.uk. This data is connected to other geomagnetic data sets, but can be used without reference to them.

The aa index is a simple global geomagnetic activity index, with units of 1 nT (nanotesla), which is produced from the K indices from two approximately antipodal observatories. At present these are Hartland observatory in the UK and Canberra observatory in Australia. The main advantage in using aa indices for research purposes is that the time series spans further back (to 1868) than any of the other planetary indices time series.Also, up to date values are produced and made available weekly, giving nearer to real time availability than any other planetary index. In between the weekly updates, BGS calculates estimated aa indices, providing real time "nowcasts" which are updated on an hourly basis. These estimates are clearly marked with the letters "Est". Although calculated by the same method, the aa indices available on this service are not the definitive values. These are published by the International Service for Geomagnetic Indices, CRPE/CNET - CNRS, 4 Avenue de Neptune, F-94107 Saint Maur, Cedex, France.

Magnetograms are records of variations in the strength and direction of the Earth’s magnetic field. Historically these magnetograms were recorded on paper using photographic techniques. In the UK, measurements were made at eight long-running observatories; Abinger, Eskdalemuir, Falmouth, Greenwich, Hartland, Kew, Lerwick, and Stonyhurst. BGS also hold magnetogram records from the Cape Evans observatory that ran continuously at Robert Falcon Scott’s Antarctic base camp during the British Antarctic Expedition 1910–13. The magnetogram collection, one of the longest running geomagnetic series in the world, provides a continuous record of more than 160 years of UK measurements. These magnetograms start in the 1840s and end in 1986 at which time digital recording of the magnetic field took over and magnetograms can be produced by computer graphic. The plots show variation in the Earth's magnetic field, typically over a 24-hour period. The collection is a valuable, partly untapped data resource for studying geomagnetic storms, space weather and the evolution of the Earth’s magnetic field. The magnetograms provide insight into: • the Earth’s outer core: long-term change (years to centuries) in the dynamo that sustains our magnetic field • space weather: short-term changes (seconds to days) in near-Earth space and on the ground • space climate: long-term change (decades to centuries) in solar activity and consequences for Earth’s environment All the above have an impact on human activities. For example, bad space weather affects technologies that we increasingly rely on, such as electrical power and GPS networks. In response to the threat of loss from degradation due to age and a desire to preserve and exploit old data, BGS undertook a programme of work to digitally photograph, archive and preserve the analogue paper records of magnetic field variation in the United Kingdom. Between 2009 and 2013, high-quality digital images of every available magnetogram were taken. These images are available to search online. Scientists and the general public around the world can now gain easy access to this historical dataset.

Magnetic time-series from the BGS SWIGS differential magnetometer method (DMM) systems. Funded by NERC, grant number: NE/P017231/1 "Space Weather Impact on Ground-based Systems (SWIGS)". These data consist of measurements of the Earth’s natural magnetic field at the Whiteadder Moor remote site (WHIR) and the natural magnetic field plus the field created by GIC at the Whiteadder Moor underline site (WHIU). The database will include .xyz files with the DMM data and one document with metadata. See Hübert et al. (2020) for further details.

BGS ran a series of Rubidium Vapour magnetometer stations, mainly in the UK, but also overseas. Data is held on 3 batches of CDs. The largest batch consists of 20CDs containing data from 1977 to 1984. The second batch contains a duplicate of the 1980 data, but also contains documentation and software to read the data files. The final batch is a single CD holding data from 1976 (a time when the stations were being set up). Data was sampled at 2.5sec intervals.