Circular of the Bureau of Standards, Брой 549

5461 angstroms 6563 angstroms A's and C's Abbe number aberration and coma aberrations to balance Achromatic Objectives addition of thicknesses air-spaced doublet algebraic aberration equations algebraic method applicable appropriate thicknesses axis borosilicate crown Calculating a Design cemented objective chr and sph chromatic aberration computed by means Condition for cementability Conrady crown glass dense flint element Second element equa exact ray tracing example eyepiece flint glass FOCUS fully corrected homogeneous light index of refraction lens design lens of unit lens powers lenses light whose wavelength longitudinal chromatic Longitudinal spherical aberration marginal ray means of eq meridional coma optical design optimum corrections overcorrection of spherical paraxial position factor preliminary design procedure for calculating radii radius of curvature referring to homogeneous relative aperture residual aberrations Robert E semiaperture shape factor spectrum line subscript referring Telescope objectives tion total curvature unit focal length V₁ V2 chr V2 chr V₁ σπ