I changed the 2-stage-lens program
so it will accept the focal length of the objective directly
(instead of assuming FL = 4 *diam for binoculars).
I have a nice Keplerian spyglass with an achromat
and a fine Plossl EP. It makes you woozy to hold the
fully-inverted and reversed image steady, but the clarity is amazing.
Anyway, it is longer than a 30mm binocular would be.
When I put an objective FL of 186mm (F6) and a power of 10 into the
2-stage lens program, I come up with an infinity-focused near range
distance of: 122 feet.
Testing this out the window, I come up with an observed near-edge of range
of : 130 ft. (the object is at 130, couldn't pick exact distances to trunks).
So.....the range modeling looks very good at F6 and various powers of F4...still great.
I can add other long-barrel range tests now..
this sounds like your formulas are working well.
Thank you for the good news,