Attempts to Observe the Absolute Intensity and the Centre-to-Limb Variations of the Sun in the Vacuum Ultraviolet Region

Calibration for two rocket-borne spectrometers to observe the absolute intensity and the centre-to-limb variations of the Sun between 1500 Å and 2000 Å is described. The procedure of the calibration is divided into two parts, (a) the measurements of the transmission of the spectrometers, and (b) the absolute detector calibration.The double dispersive spectrometer has been planned to be launched in September 1970, but it was postponed until the coming winter, and the single dispersive spectrometer will be launched in January 1971.