A quote that one has to be rich to engage in science?

To expand upon Gerhard's comment, I would add the following:

In English, the -acy suffix tends to denote the nounification of an adjective and the -ation suffix tends to denote the nounification of a verb.

Obviously, 'conjugate' can act as both an adjective and a verb e.g. '$x$ and $y$ are conjugate' or 'One may conjugate $x$ by some element to get $y$'

Since these phrases are mathematically the same, there is thus no mathematical difference between '$x$ and $y$ are equal up to conjugacy' and '$x$ and $y$ are equal up to conjugation'