2.2.0 spase://SMWG/Instrument/SDO/HMI HMI 2012-03-07T04:58:10Z The SDO (Solar Dynamics Observatory) HMI (Helioseismic and Magnetic Imager) studies the origin of solar variability by characterizing and developing an understanding of the sun's interior and the various components of its magnetic activity. It extends the capabilities of the SOHO/MDI instrument to continuous full-disk coverage at higher spatial resolution and vector magnetograms. HMI observes the full solar disk in the Fe I absorption line at 6173A with a resolution of 1 arc-second. HMI consists of a refracting telescope, a polarization selector, an image stabilization system, a narrow band tunable filter and two 4096 pixel CCD cameras with mechanical shutters and control electronics. The continuous data rate is 55Mbits/s. Images are made in a sequence of tuning and polarizations at a 4-second cadence for each camera. One camera is dedicated to a 45s Doppler and line-of-sight field sequence while the other to a 90s vector field sequence. All of the images are downlinked for processing at the HMI/AIA Joint Science Operations Center at Stanford University. spase://SMWG/Person/Philip.H.Scherrer PrincipalInvestigator HMI web site at Stanford U. http://hmi.stanford.edu Imager HMI spase://SMWG/Observatory/SDO