The occurrence of a total eclipse at Tartagal, Argentina, on November 12, 1966, prompted a rocket sounding experiment to determine temperature, wind, and ozone perturbations in the stratosphere caused by the eclipse. Soundings were made in the 65-to 30-km region of the atmosphere before, during, and after the total eclipse. Twelve rockets were successfully fired; nine of the rocket instruments were designed to measure temperature and three were designed to determine ozone concentration in the atmosphere. Wind speed was determined for each sounding from the trajectory of the radar-reflective parachute.

Four different rocket techniques provided data on ozone at Wallops Island, Virginia, during the Aladdin 74 program. The entire altitude region from 19 to 108 km was covered, the different techniques providing overlapping profiles that included the afternoon of June 29 and the early morning of June 30 (local time). There were systematic differences between the chemiluminescent sonde and UV absorption techniques, the sonde giving the greater densities. These differences became larger with increasing altitude up to the maximum common altitude, 62 km. Both airglow and absorption techniques indicate a density minimum at 81 km of 1–3 × 107 cm−3 and agree within the experimental errors in the overlap region down to 72 km. Above 90 km the airglow experiment shows a relatively constant but structured density profile. The mass spectrometer measured a considerably higher ozone density at 90 km with a rapidly decreasing scale height up to 108 km. The experimental results are compared with photochemical‐transport models.

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A simple rocket-borne system has been developed for deriving nitric oxide concentration in the mesosphere from measurements of resonantly scattered solar ultraviolet radiation in the NO gamma band near 2150 •. The NO signal is extracted from a background of Rayleigh-scattered light by a direct measurement of this scattered light by use of an NO absorption cell. This system was utilized to measure the NO concentration above White Sands, New Mexico, in the altitude range from 69 to 101 km. The derived NO profile shows a concentration of about 3 x 10 7 cm -3 at 67 and 100 km with a deep valley (more than an order of magnitude less) at about 84 km. Comparison with model calculations indicates that the time constant forNO chemistry is smaller than or comparable with that for transport.

A rocket‐borne ozonesonde that utilizes the chemiluminescent principle for the measurement of ozone concentration in the upper atmosphere has been developed. The sonde is deployed in the mesosphere by a small meteorological rocket (Arcas), and ozone concentration is measured as the instrument descends on a drag parachute. This instrument was flown during and before the total solar eclipse of November 12, 1966, at Tartagal (22°32′S, 63°50′W), Argentina, with the cooperation of scientists from that country. Ozone was monitored as the sonde passed through the total eclipse shadow beween 60 and 54 km and registered a higher concentration than the sounding made a day earlier at about the same time. A decrease in the ozone concentration was noticed as the sonde emerged from the shadow of the total eclipse. Ozone concentration at 57 km during total solar eclipse was measured to be 3.7 × 10−3 cm km−1 as compared with 1.4 × 10−3 cm km−1 measured a day earlier at the same altitude. No marked effect on the ozone concentration in the upper stratosphere was noted during the partial eclipse conditions under which that region was observed.