Afcrl - 66 - 75 Application of Electro - Optics to Auroral Studies - Phase Ii

During 1964-65 a continuing investigation was performed to examine the feasibility of obtaining information on the time-changing characteristics of the aurora and night air glow by low-light level image orthlcons at the RadioOptical Observatory of the General Electric Company's Research & Development Center In Schenectady, New York. Although no auroras were detected during this interim period, wavelength and intensity calibrations on a spectrograph of special design using the image orthicon detector were accomplished with spectral lamps and night air glow emissions. Included photographs of night air glow demonstrate that the image orthicon is at least 1000 times faster than photographic film when detecting weak "point" or "line" sources under high contrast conditions. Twenty photoelectrons are sufficient to record a spectral line. Sensitivity calibrations were also performed on a 16" f/20 telescope, where the North Polar Sequence of Stars provided a standard calibrated star field. Within 10 seconds, 18th magnitude stars were detected. Further analysis is given on the data recorded during the September 1963 aurora and initially reported in the Final Report of Phase I, 1963 AFCRL 64-209.