Uranus and Neptune cannot be seen without a telescope. The rest of the planets can all be seen, but not necessarily at the same time. Monday: lunes/lundi = Moon day. Tuesday: martes/mardi = Mars day. Wednesday: miércoles/mercredi = Mercury day. Thursday: jueves/jeudi = Jupiter day. Friday: viernes/vendredi = Venus. Saturday = Saturn day. Sunday = Sun day. See how it all works out?