US Historic Declination Calculator |
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This programs derives a table of secular change in magnetic declination for a specified
point in the conterminous United States. It utilizes the USD polynomial and the IGRF
spherical harmonic models. Declination is calculated using the current World Magnetic
Model (WMM) or International Geomagnetic Reference Field (IGRF) model. While results
are typically accurate to 30 minutes of arc, users should be aware that several environmental
factors can cause disturbances in the magnetic field. |
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