Absolute solar 30.4 nm flux from sounding rocket observations during the solar cycle 23 minimum

A transmission grating extreme ultraviolet (EUV) spectrometer, nominally identical to the Charge, Element, and Isotope Analysis System/Solar EUV Monitor (CELIAS/SEM) instrument on the Solar and Heliospheric Observatory (SOHO), has obtained accurate measurements of the integrated absolute solar extreme ultraviolet irradiance in an 8 nm band pass centered at 30.4 nm. The spectrometer also measured the EUV/soft X-ray flux, but those data will be reported in a later paper. The instrument was launched on two sounding rocket flights from White Sands Missile Range, New Mexico, on June 26, 1996, and again on August 11, 1997, to provide a SOHO underflight calibration database in the EUV. The full disk solar 30.4 +/- 40 nm fluxes measured by it on the above two days were 1.21 x 10 exp 10 and 1.42 x 10 exp 10 photons/sq cm/s at 1 AU, respectively. These measurements have an absolute 1 sigma uncertainty of 8.1 percent. (Author)