It is known that a space-based solar shield located in the first (inner) collinear libration point of the Sun-Earth system could be useful to offset the greenhouse effect and to control the global temperature: several such projects are already published and discussed. Some dynamical aspects of such projects for celestial mechanics are shown in the frame of the photogravitational restricted circular three-body problem. Some astronomical aspects of shield visualization are discussed from the point of view of shadowing problem as an obstacle for astronomical visual or radio-observations of Sun.