Tasco OffShore 21 - Page 6

6
Object Size Scale
Object Distance Scale
Angle Index
Reticle Angle Index Scale
Base to Top of Lighthouse= 2.5
Example: Top of lighthouse is level
with 2.5 on reticle angle scale. Rotate
calculator dial so “2.5” on angle index
is opposite the mark. If lighthouse is
known to be 100’ high, distance to
the lighthouse is 4000’.