SOHO Intercalibration Joint Observing Program 011 Woods/Hassler Sounding Rocket Cross Calibration Flight Contributors: Don Hassler (SwRI), Tom Woods (CU/LASP), Paal Brekke (UiO), Bill Thompson (GSFC), Udo Schuehle (MPAE), J.P. Delaboudiniere (IAS), Larry Gardner (CfA), Silvano Fineschi (SAO), C. Korendyke (NRL) Sounding Rocket Flight Overview: The Woods/Hassler sounding rocket payload consists of a suite of XUV and EUV full disk irradiance instruments (Tom Woods, PI) and EUV coronal imagers (Don Hassler, PI) which are radiometrically calibrated at NIST/SURF. The next flight is scheduled to be launched at 1800 UT on April 19, 1997, however, the exact launch date will depend on solar conditions. The primary objective of the irradiance instruments for this flight is to obtain a radiometrically calibrated "typical" or "characteristic" solar minimum full disk EUV solar spectrum, and provide a radiometric calibration for SOHO. The primary objective of the EUV imagers is to measure the coronal helium abundance (with respect to hydrogen), as well as provide radiometrically calibrated full disk images to compare with the irradiance observations and SOHO observations. The irradiance instruments consist of a 1/4 m EUV Grating Spectrograph (EGS) which obtains full disk solar irradiance spectra over the wavelength range 250-1200 A with 2 A spectral resolution (6-10 % absolute radiometric calibration) and 5 XUV Photometers (Xps) which cover the wavelength range 10-400 A with roughly 100 A bandpass each and an absolute radiometric calibration of 10-20%. The SOLSTICE instrument (Gary Rottman, PI) on the UARS satellite obtains daily full disk irradiance observations in the wavelength range 1200-1600 A with an absolute radiometric uncertainty of 3-5% to be compared with these rocket observations and SOHO/SUMER. The EUV Imagers for this flight consist of a Fe IX/X 171 A multilayer mirror telescope and H I Ly-alpha 1216 A telescope to obtain radiometrically calibrated full disk images and an off-limb (1.2 to 2.0 solar radii) He II 304 A multilayer mirror coronal imager. The Fe X 171 A and He 304 A imagers both use a 256 x 256 CODACON microchannel plate detector with roughly 10 x 10 arcsec spatial resolution, and the Ly-alpha 1216 A imager uses a 128 x 128 CODACON microchannel plate detector with roughly 20 x 20 arcsec spatial resolution. SOHO Instrument Operating Details: CDS: The NIS operational sequence consists of spatially resolved full disk spectral images in 4-6 wavelengths with 4 arcsec resolution and a full disk integrated spectral atlas over the entire NIS spectrum (no spatial resolution). The GIS operational sequence will consist of 4 x 4 arcmin disk center rasters in all 4 wavelength bands. SUMER: The SUMER operational sequence consists of a quiet Sun reference spectrum over the full spectral range (500-1600 A) at eight slit positions along a diameter (N to S) at central meridian. EIT: The EIT operational sequence consists of obtaining co-temporal full disk images in each of the four wavelength bands, Fe IX/X 171 A, He II 304 A, Fe XII 195 A, and Fe XIV 284 A. UVCS: The UVCS operational sequence consists of obtaining H I Ly- alpha 1216 A intensities between 1.2 and 2.0 solar radii above the equatorial limb (E or W limb TBD) and a Ly-alpha 1216 A disk observation (TBD). LASCO: The LASCO operational sequence consists of obtaining C2 pB observations between 1.2 and 2.0 solar radii above the equatorial limb (E or W limb TBD).