Back on time, during the seventies, Jethro Tull released a song called "Too old to rock and roll, too young to die..." and that used to be a nick for ray lomas, the most important person on that L. P. But, what it really means is
Osa Mayor, as far as I do concern...
But the Big Dipper is an asterism -- a smaller part of a constellation (Ursa Major, in this case) that has its own name/identity, not the constellation itself. Is there no term in Spanish for the subgroup of stars in la Osa Mayor which English-speakers call "the Big Dipper"?
To clarify, the "big dipper" is not the same as Ursa Major/Ursa Mayor/Osa Mayor... Ursa Major (also known as the Great Bear) is a larger constellation that CONTAINS the 7 stars that make up the Big Dipper. The Great Bear comes from the Greek/Roman constellation system. The Big Dipper, however, is more common in North American Folklore. The two concepts are totally unrelated.
So saying "The Big Dipper" = Ursa Mayor is like telling someone who ask how you say "arm" in Spanish to just say "cuerpo" (body).
I came here searching for the answer to this questions but unfortunately I am still unsure. If you want to tell the story of the Big Dipper, it is important that it still be described as a spoon. So calling it a Giant Bear as people have suggested would be confusing. Whenever I tell the story, I am just going to say Cuchara Grande, which although potentially incorrect will certainly be more in the realm of what I would like to convey.
Reference for those who seek further clarification: laeff.inta.es/users/bmm/weblog/starmap-large.gif
As you can see Ursa Mayor is NOT the same as the big dipper.