MASS starts regular operation at Cerro Tololo. The observers are Sylvain Baumont and Joselino Vasquez.
Example of data taken on the night of April 17/18 by A. Tokovinin and S. Baumont.
Top: Cn2 profile for the night of April 17/18 2002. Scale of turbulent-slab intensities is indicated by the bar on the right. Data are taken at 1-min. rate, with some gaps.
Bottom: comparison of the full seeing as measured by DIMM (black line) and the free atmosphere seeing (only layers above 1 km) measured by MASS (red dots). "Free" seeing is always less than full seeing, except occasional moments when upper layers dominate over ground/boundary layer.
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| On the night of April 17/18 a strong intermittent layer at an altitude around 3 km appeared. By the end of the night, the turbulence became very weak: DIMM measured the seeing down to 0.3 arcsecond, isoplanatic angle reached 3 arcseconds. The short spike around 9h UT is not matched by DIMM data, probably because the turbulent patch was very localized while both instruments looked at different stars (DIMM - Iota Sco, MASS - Lambda Sco). |