A NEW METHOD OF MEASURING ATMOSPHERIC SEEING

A new method of measuring the integral C-n(2) in the atmosphere from s tellar scintillations is proposed, This method is based an the varianc e of the logarithm of the ratio of intensities in circular and annular apertures. For outer and inner aperture diameters of 6 and 4 cm, resp ectively, the weighting function, which determines the sensitivity to C-n(2), is constant at heights above 4 km. The integral C-n(2) over th e whole thickness of the atmosphere can be measured by placing an annu lar aperture behind the exit pupil of a telescope at a virtual height of 4 km. When observing a 2.(m)5 star for 100 s, a 0.5 '' seeing can b e measured with a relative error of 0.35%. The new method may prove to be simpler and cheaper than traditional differential seeing monitors.