Many researchers have documented the difficulties for learners of different ages and preparations in
understanding basic astronomical concepts. Traditional instructional strategies and communication
media do not seem to be effective in producing meaningful understanding, or even induce
misconceptions and misinterpretations. In line with recent proposals for pedagogical sequences and
learning progressions about core concepts and basic procedures in physics and astronomy education,
in this paper we suggest an intermediate, essential step in the teaching path from the local
geocentric view of the Earth?Sun system to a heliocentric one. With this aim we present data
collected over a day and a year from an instrument we call the ?parallel globe?, a globe positioned
locally homothetic to the Earth. Some analyses are suggested, in particular of the phenomenon of
illumination of the Earth and its variations, that are consistent with the proposed instructional
objectives.