Info

upr 1

This is identical with the result of Eq. (3.87) for a 1-mirror telescope if we replace f1 by f , the focal length of the 2-mirror combination. For the cases of Table 3.3 with y1 and the final focal lengths normalized to unity, the field coma is identical for the 1-mirror and classical Cassegrain and Gregory cases, an important result. However, it must be remembered that the classical 2-mirror telescopes will give a lower value in practical cases if their relative aperture is smaller.

The field astigmatism is given by Eq. (3.61). With E SI = 0, the last term is again zero. The other stop-shift term in the bracket can be written f (2di£ + f!) , which contains in the bracket twice the stop-independent coma of Eq. (3.60). In the general case, then, the classical telescope has the astigmatism

since £ = 0. If the stop is at the primary, this reduces to

Telescopes Mastery

Telescopes Mastery

Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!

Get My Free Ebook


Post a comment