Astronomy and Astrophysics (ISSN 0004-6361), vol. 252, no. 2, Dec. 1991, p. 861-865. Research supported by CICYT.
Martinez Pillet, V.; Sanchez Almeida, J.
A technique for obtaining an ideal two-mirror coude system with no instrumental polarization is described. A half-wave plate positioned between the two mirrors with the proper orientation produces the desired effect. The level of spurious polarization is limited by the characteristics of the retarder and the similarity of the mirrors. The telescope design and accuracy are discussed.