{
  "Spase": {
    "xmlns:xsi": "http://www.w3.org/2001/XMLSchema-instance",
    "xmlns": "http://www.spase-group.org/data/schema",
    "xsi:schemaLocation": "http://www.spase-group.org/data/schema http://www.spase-group.org/data/schema/spase-2_2_2.xsd",
    "Version": "2.2.2",
    "Instrument": {
      "ResourceID": "spase://SMWG/Instrument/Ground/MaunaLoaSO/MK4",
      "ResourceHeader": {
        "ResourceName": "MLSO_ACOS_MK4",
        "ReleaseDate": "2015-10-23T00:00:00Z",
        "Description": "The Mark-III instrument was the third generation white \nlight K-coronameter instrument at MLSO, and it operated from 4 February, \n1980, through 30 September, 1999.  The field of view of the Mark-III \nK-Coronameter (Mk3) was 1.122 to 2.44 solar radii (as measured from sun \ncenter). The sun's corona was scanned by a linear array detection system \nwhich is rotated in solar position angle about the center of the solar disk. \nIt took about three minutes to acquire one coronal image.\nThe Mark-III K-Coronameter data are scaled such that 104.4 pixels \ncorresponds to one solar radius. Spatial sampling is 10 arcseconds \nradially by 0.5 degrees in azimuth. All data are rotated so that solar \nnorth is oriented straight up; solar north is known to within three degrees. \nDaily averaged images and mass ejection images from the K-Coronameter have \ninstrumental `vignetting' left in the data to offset the coronal radial \ndensity gradient, allowing for better viewing of the corona. Calibrated \nimages in units of polarization brightness (pB) are available and may be \nrequested via the E-mail address listed above.\nThe Mark-IV K-coronameter, was constructed by HAO in collaboration with \nRhodes College (Memphis, Tennessee). It has been in operation since \nOctober, 1998, at MLSO.\nThe Mark-IV K-coronameter replaces its predecessor, the Mark-III and \nfeatures a high speed liquid crystal polarization modulator, a low noise \nCCD line array detector, and an achromatic polarizing beam splitter to \nmeasure Stokes I, Q, and U. Mark-IV produces polarization brightness maps \nof the lower corona in white light (700 to 900nm) from about 1.14 to 2.86 \nsolar radii at a 3-minute cadence. Its plate scale is 5.95\"/pixel, with \ndata accuracy of approximately %15 and a noise level of approximately \n4x10-9 B/Bsun.\nThe Mark-IV instrument is a significant improvement over its predecessor \nin the following ways: lower system noise due to an improved detector and \nassociated electronics, better sky noise rejection due to improved \npolarization optics and faster polarization modulation rate, higher \nspatial resolution, and a wider field of view.\nThese improvements result in higher quality polarization-brightness \nimages which may be taken over a greater range of sky conditions than \nwas heretofore possible.\nFor information about the Mk4 K-Coronameter calibration technique, see \nElmore et al. (199?).",
        "Contact": {
          "PersonID": "spase://SMWG/Person/Thomas.E.Holzer",
          "Role": "GeneralContact"
        },
        "PriorID": "spase://SMWG/Instrument/MaunaLoaSO/MK4"
      },
      "InstrumentType": [
        "Imager",
        "Coronograph",
        "Photopolarimeter"
      ],
      "InvestigationName": "ACOS/MK4 at MLSO",
      "ObservatoryID": "spase://SMWG/Observatory/Ground/MaunaLoaSO"
    }
  }
}