|Here are possible two type of calculations:
1. Using glass catalog data; Enter doublet focal length, select a glass type for both
front and rear lens from the Schott glass catalog (for example BK7 and F2). This will
fill with data, the refractive indices fields N1, N2, N3 for
a fixed wavelengths and finally press the "Calc" button.
2. Using user defined indices and wavelengths; Specify the doublet's focal length.
Enter three refractive indices N1, N2, N3 and correspond
wavelengths l1, l2, l3
for both front and rear doublet's lens and finally press the "Calc" button.
Note: This calculator is Java Script version of a BASIC program written by
John A. Church in "Designing an Aplanatic Doublet" page 450 of the November 1984 issue of
Sky and Telescope magazine.