Absorption of light passing through the glass is a bigger problem for Cassegrain reflectorsthan achromatic refractors.

Question

Quizplus · Accepted Answer

Cassegrain reflectors use mirrors to reflect light, so there is no glass involved that could absorb light. Achromatic refractors, on the other hand, use lenses made of glass which can absorb some of the light passing through them. Cassegrain reflectors use mirrors to reflect light, so there is no glass involved in the light path. Achromatic refractors, on the other hand, use lenses that can absorb some of the light passing through them. Therefore, absorption of light passing through the glass is more likely to be a problem for achromatic refractors than for Cassegrain reflectors.

Absorption of Light Passing Through the Glass Is a Bigger