Winegasman,
The "zenith" angle of a cantilever means the direction the cantilever points when viewed from the zenith, i.e., from directly overhead looking downward.
Of course one can't actually adjust zenith this way (though it would be optimal) for the obvious reason that the cartridge body and headshell block your view of it.
We adjust zenith by looking at the cantilever from dead ahead. As pointed out by Mark, a mirrored protractor like the TTB, Mint or Wally offers the only practical way to have any certainty that we're actually viewing the null point from precisely along the intended alignment line. If you move your eye off line by the tiniest amount, the dual images of printed/scribed line vs. its reflection go out of synch, letting you know you're out of position. No paper or plastic protractor offers that, and no one who's only used them has any idea whether their cantilever is aligned or not.
***
The "battle" above over Technics vs. Mint was saddening. The only people saying the Technics is good enough are those who've never tried anything else, never heard the results. Why is it so tempting for humans to invent theoretical "explanations" to discount things we're unwilling to test, even in the face of overwhelming testimony from those who have tested. The popes treated Galileo that way, and we haven't improved much since.
The "zenith" angle of a cantilever means the direction the cantilever points when viewed from the zenith, i.e., from directly overhead looking downward.
Of course one can't actually adjust zenith this way (though it would be optimal) for the obvious reason that the cartridge body and headshell block your view of it.
We adjust zenith by looking at the cantilever from dead ahead. As pointed out by Mark, a mirrored protractor like the TTB, Mint or Wally offers the only practical way to have any certainty that we're actually viewing the null point from precisely along the intended alignment line. If you move your eye off line by the tiniest amount, the dual images of printed/scribed line vs. its reflection go out of synch, letting you know you're out of position. No paper or plastic protractor offers that, and no one who's only used them has any idea whether their cantilever is aligned or not.
***
The "battle" above over Technics vs. Mint was saddening. The only people saying the Technics is good enough are those who've never tried anything else, never heard the results. Why is it so tempting for humans to invent theoretical "explanations" to discount things we're unwilling to test, even in the face of overwhelming testimony from those who have tested. The popes treated Galileo that way, and we haven't improved much since.