NSSDCA ID: 1971-083A-02
Mission Name: OSO 7This experiment was designed (1) to study the morphology of the corona in white light and the extreme UV in relation to active phenomena, such as plages and flares in the lower solar atmosphere, and (2) to correlate the white light corona with the extreme UV corona and with solar and interplanetary magnetic fields. The instrumentation was located within the pointed section of the spacecraft and consisted of (1) a white-light coronagraph for use in the pointed mode to record the outer corona of the sun from approximately 3 to 10 solar radii in the visible band of 3900 to 6500 A and (2) an extreme UV coronagraph for use in the raster mode to record the upper chromosphere and lower corona fully to two solar radii and partially to five solar radii in the band from 170 to 550 A. The white-light instrument was a modified Lyot coronagraph that artificially eclipsed the sun with a spar-mounted external occulting disk assembly mounted approximately 76 cm in front of the instrument. The faint outer corona could then be observed against the black sky of space. The image was stored in a SEC Vidicon tube with 256 raster lines, each having 256 picture elements. The distance between picture elements was 1.25 arc-min. The extreme UV coronagraph required no occultation device since the solar disk was not an overwhelming source of extreme UV radiation. There were four open-to-vacuum channel photomultiplier detectors in the image plane behind pinhole apertures in an aperture plate. The assembly was scanned across the solar image in a raster mode. The central aperture detector had a spatial resolution of 20 arc-s. The remaining aperture detector combinations were offset, excluding the disk, and had a resolution of 60 arc-s. In a large raster mode, the scanned areas overlapped. The experiment operated normally until March 1972, when it became partially operable. The extreme UV coronagraph degraded until it became useless in September 1973.
Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. Martin J. Koomen | Other Investigator | US Naval Research Laboratory | koomen@maple.nrl.navy.mil |
Dr. Donald J. Michels | Other Investigator | US Naval Research Laboratory | michels@lasco11.nrl.navy.mil |
Dr. Richard Tousey | Principal Investigator | US Naval Research Laboratory |