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..

Hello Martin,

this sounds like your formulas are working well.

Thank you for the good news,

JG