2.7.1 https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions spase://NASA/NumericalData/SDO/HMI/LOS_Magnetogram/PT45S NASA NumericalData SDO/HMI line-of-sight Magnetogram, 45-Second Data https://doi.org/10.48322/f2z0-rs29 2025-12-04T13:31:26Z 2024-10-11T00:08:46 Metadata created by SY 2024-11-18T00:08:46 Added DOI by SY 2025-08-04T00:08:46 Added HelioViewerID to Extension 2025-09-18T11:27:08Z Added ResourceType and NamingAuthority. Changed http to https in top-level schemaLocation attribute. Fixed version number separator in top-level schemaLocation attribute. Matched version number in schemaLocation attribute to updated value in Version tag. ZCB 2025-09-30T14:25:18Z Updated PublishedBy name to match ROR Registry. ZCB 2025-12-04T13:31:26Z Added MetadataRightsList. Updated to 2.7.1. ZCB Magnetograms are maps of the observed solar magnetic field in the photosphere. The line-of-sight component of the field can be accurately measured as it evolves in time over the full visible disk of the Sun. The HMI instrument exploits the Zeeman effect, which allows the strength of the line-of-sight component of the magnetic field to be determined by measurements of the spectral line in circularly polarized light. HMI makes two independent measurements of the line-of-sight component of the photospheric magnetic field. One is collected every 45 seconds with the HMI Doppler camera. The other is computed every 720 seconds using filtergrams recorded by the Vector Field camera. The spatial resolution is 1 arc second (half arc-second pixels) and the full disk images are collected on a 4096**2 detector. The noise level is nominally between 5 and 10 Gauss. HMI really measures flux density in Mx/cm2 in each pixel. The HMI Consortium: Stanford University (USA); NASA Goddard Space Flight Center (USA); Lockheed Martin Solar and Astrophysics Laboratory (USA); National Center for Atmospheric Research (USA) 2011-01-21T00:00:00 Stanford University spase://SMWG/Person/Philip.H.Scherrer PrincipalInvestigator spase://SMWG/Person/Rick.Bogart GeneralContact The HMI website at Stanford http://hmi.stanford.edu/ The SDO/HMI Instrument paper https://doi.org/10.1007/s11207-011-9834-2 spase://SMWG/Repository/Stanford/HMI-AIA.JSOC Online Open JSOC Data Center http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.M_45s[2020-01-01T00:00:00/60m] Change the date and the time to find the HMI data. SDO/HMI Data Search via Virtual Solar Observatory https://sdac.virtualsolar.org/cgi/search?time=1&instrument=HMI&spectrum=1&version=current&build=1 VSO path to JSOC-resident SDO HMI data files FITS spase://SMWG/Instrument/SDO/HMI Magnetogram 2010-03-29T07:49:47 -P3D PT45S Sun Sun.Photosphere FITS Data Array Line-of-sight magnetic field strength PT45S gauss LineOfSight Magnetic Cartesian HPC Array size: 4096x4096 Pixel Resolution: 0.504 arcsec 19