D. Dialetis

The variation of the mean size of the photospheric granules close to and away from a sunspot

We study the mean size of granules as a function of distance from the boundaries of the sunspot penumbra. We use for the determination of the mean size two different methods, a visual and a photometric. In all cases the mean diameter of the granules away from the spot was greater than the mean diameter of the granules in the neighbourhood of the penumbra. Our study is based on an excellent sequence of photos, taken at the Pic-du-Midi Observatory on May 11, 1979.

Zenith photoelectric measurements during the annular solar eclipse of April 29, 1976

Measurement of the light intensity in the zenith, obtained during the annular solar eclipse of April 29, 1976 are given in three wavelength bands (centered on λs 4800, 5400 and 6100 Å). The observed differences in the three wavelength regions have been examined and compared with calculations taking into account limb darkening.

The Variation of the Mean Size of the Photospheric Granules Near and Far from a Sunspot

We study the mean size of granules as a function of the distance from the boundaries of the sunspot penumbra. We use for the determination of the mean size two different methods, a visual and a photometric one. In all cases the mean diameter of the granules remote from the spot was greater than the mean diameter of the granules in the neighbourhood of the penumbra. Our study is based on an excellent sequence of photos, taken by one of us (R.M.) at the Pic du Midi Observatory in May 11, 1979.