We are building a telescope to launch into space. The performance of the telescope depends on the choice of $3$ lenses. Additionally, we suspect that the performance depends on the telescope operator, of which there are two. Finally, the runs necessary to test the telescope have to be performed across $4$ days, because the telescope actually heats$-$up during the test, and that heat may affect performance. What is the response, and what are the factors in this experiment? Also identify each of the factors as treatment or nuisance. Hint: This is one of the ambiguous questions I've been talking about. You must use your common sense and

the description of the problem to resolve any ambiguity.