This paper explores a semi-formal intervention in the public learning and understanding of science (PLUS) by involving school children and their family adults in project work in astronomy. Mixed generation ‘family teams’ attended two ‘Family Science Evenings’ at the children’s primary schools and undertook to tackle and report on home-based projects over the intervening six week period. The projects required the family teams to collaborate in their learning and the results, in terms of enhanced interest and enjoyment of astronomy, were very positive. The evaluation of the research data considers outcomes at three levels: (i) general evaluative comments, (ii) gains for the family teams involved; and (iii) gains in the general public understanding of science. The research raises a number of issues, and highlights that, particularly in such a mixed context as this, precise learning gains are difficult to assess.