Exact calculation of conic constants and baffles for any two-mirror aplanatic telescope.

To calculate the conic constants of the primary and secondary mirrors of any aplanatic two-mirror telescope, nonexact equations have been used considering third-order approximations, although it was not considered that there is an infinite number of conic constants. In this paper, exact nonlinear equations are obtained; with them, the two conic constants of the mirrors are calculated without approximations. We also find that the conic constants depend on the position at the stop where the calculation is carried out, and there are always residual aberrations. In addition, a procedure is established for the exact calculation of the baffles. Finally, examples show the differences between exact and third-order calculations.