Line Spectra of Delta and pi Scorpii in the Far-Ultraviolet

During the past year three Aerohee rockets were launched to obtain stellar ultraviolet line spectra using two objective spectrographs with f/2 8chmidt cameras. One corrector was quartz and the other calcium fluoride. The whole rocket was directed toward the target field by a 8pace General attitude control system. Limit-cycle jitter parallel to the dispersion was reduced to + 16" by pivoting the spectrographs in this direction and attaching to them a large gyro rotor gimbaled about a perpendicular direction. Thus fine stabilization in one coordinate was achieved by a purely mechanical system. On the first two ffights the attitude control system failed to stabilize the rocket. On the third flight both coarse and fine systems operated properly, but the parachute failed on re-entry so that the impact damaged the payload beyond repair and admitted light into the film cassettes. Most of the films were totally fogged, but underdeveloping one from the calcium-fluoride camera showed wide spectra of the early B-type stars & and 7r 8corpii with a resolution of about 1 A. The spectra extend from 1260 to 1720 A for & 8co and from 1260 to 2180 for ir 8co. Many lines are visible in both spectra, all in absorption. Wavelengths are given here for twenty-nine lines, of which twelve are common to both spectra. Identifications include C ii X 1335, 8i iv XX 1394,1403, C iv X 1549, He ii X 1640 A, and probably a number of features due to C iii multiplets. The spectra are too weak to permit an)' useful intensity calibration, but in general they seem to be consistent latest models now available for stars. A number of interstellar features, due to 0 i at 1302 A, 8 ii at 1526 A, and Al ii at 1671 A, are apparently also present, and the C ii lines may be partly interstellar.