Ground-based measurements of solar diameter
  The solar diameter changes or not? Whatever will be the answer the methods used for its measurements are more and more challenging, and facing new astrophysical and optical problems since the required space resolution is of astrometric quality. A quick overview on different methods is here presented, as well as the problem of the solar limb definition, emerging after the flash spectrum during eclipses. 
Costantino Sigismondi
astro-ph.SR astro-ph.IM