Abstract:
The Geomagnetic observatory in Panagjurishte (PAG) is established in 1937 – first on the Balkan Peninsula and unique in Bulgaria and during more than 75 years performs the absolute measurements of the geomagnetic field elements and continuous registration of their variations. Until the transfer of the Geomagnetic Observatory from the Military Topographic Service at the Ministry of Defense to the Geophysical Institute of the Bulgarian Academy of Sciences in 1961, and some time afterwards, the diurnal mean, monthly mean, and annual mean values of the elements of the geomagnetic field were obtained from the records on the magnetograms – primarily to reduce field geomagnetic measurements to a common epoch, with no data being published.
To obtain a 60-years long record of the hourly mean values of the geomagnetic field component a lot of efforts have been performed including scan of the old magnetic yearbooks, digitalization of the images and verification of data. As a result, geomagnetic database is created and made available through the institutional web-page and WDC Edinburgh providing basis for scientific research and analysis.

Keywords:
PAG observatory, geomagnetic variations, geomagnetic records, secular variations, hourly mean values