{"@type": "dcat:Dataset", "accessLevel": "public", "bureauCode": ["026:00"], "contactPoint": {"@type": "vcard:Contact", "fn": "NASA Space Physics Data Facility", "hasEmail": "mailto:NASA-SPDF-Support@nasa.onmicrosoft.com"}, "description": "Dopplergrams are maps of solar surface velocity. The HMI (Camera 2) instrument takes 72 filtergrams to construct a single dopplergram. Six filtergrams are taken in six positions across the nominal 6173.3 \u212b spectral line; each filtergram is taken in two polarization states (right circularly polarized (RCP), or Stokes I-V, and left circularly polarized (LCP), or I+V). Assuming that the absorption line is a Gaussian and that the HMI filter transmission profiles are delta functions, the Fourier coefficients can be calculated and are then used to estimate the line-of-sight magnetic field strength B.", "distribution": [{"@type": "dcat:Distribution", "downloadURL": "http://hmi.stanford.edu/", "format": "BIN", "mediaType": "application/octet-stream"}, {"@type": "dcat:Distribution", "downloadURL": "http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.V_45s%5B2020-01-01T00%3A00%3A00%2F60m%5D", "format": "BIN", "mediaType": "application/octet-stream"}, {"@type": "dcat:Distribution", "downloadURL": "https://doi.org/10.1007/s11207-011-9834-2", "format": "HTML", "mediaType": "text/html"}, {"@type": "dcat:Distribution", "downloadURL": "https://sdac.virtualsolar.org/cgi/search?time=1&instrument=HMI&spectrum=1&version=current&build=1", "format": "BIN", "mediaType": "application/octet-stream"}], "identifier": "https://doi.org/10.48322/e9dg-yp34", "keyword": ["dopplergram"], "landingPage": "https://doi.org/10.48322/e9dg-yp34", "license": "https://www.usa.gov/government-works", "modified": "2026-04-20", "programCode": ["026:000"], "publisher": {"@type": "org:Organization", "name": "SDO HMI-AIA JSOC at Stanford"}, "theme": ["Heliophysics"], "title": "SDO/HMI line-of-sight Dopplergram, 45-Second Data"}