Detection of airglow lines from EURD

The Spanish Minisat 01 satellite, which was succesfully launched last April 21, carries three instruments onboard: LEGRI, EURD and CPLM. EURD is designed for high-sensitivity spectroscopy of diffuse radiation in the wavelength range from 350 to 1100 Å, with spectral resolution of 5 Å (Bowyer et al. 1997). The spacecraft is placed in LEO orbit at an altitude of 575 km with an inclination of 151 degrees. After in-orbit test of all the systems of the satellite and the scientific payload, observations with EURD started in June 10. First light images showed the presence of strong emission lines produced by geocoronal and interplanetary resonantly scattered solar lines. In this communication, we present initial integrated spectra in the short and long wavelength spectrometers of EURD (350 to 800 Å and 500 to 1100 Å respectively) as well as a comparison with the previously known emission line structure from other space missions. Data taken by EURD represent a significant improvement over previous data at these wavelenghts, and integration during a number of orbits has revealed lines of the EUV nightglow spectrum with a good signal-to-noise, and new identified geocoronal unes of the HI Lyman series. Interstellar emission lines are not expected to show up until at least 1000 hours of effective observing time are accumulated.