1211.4394 (Costantino Sigismondi)

Solar diameter, eclipses and transits: the importance of ground-based observations    [PDF]

Costantino Sigismondi

According to satellite measurements the difference between polar and equatorial radius does not exceed 10 milliarcsec. These measurements are differential, and the absolute value of the solar diameter is not precisely known to a level of accuracy needed for finding variations during years or decades. Moreover the lifetime of a satellite is limited, and its calibration is not stable. This shows the need to continue ground-based observations of the Sun exploiting in particular the methods less affected by atmospheric turbulence, as the planetary transits and the total and annular eclipses. The state of art, the advantages and the limits of these two methods are here considered.

View original: http://arxiv.org/abs/1211.4394