Bushnell MARINE Binoculars Instruction Manual page 6

HOW TO USE THE RETICLE
The vertical scale (reticle) visible through the left half of the binocular, above the compass display, allows you
to calculate distance to an object if you know its height, or to calculate the height of an object if you know its
distance from you. Each mark on the vertical scale has a value of 5 MIL (1 Mil is equivalent to an angle that
can determine an object one meter in height at a distance of 1000 meters).Therefore, if a navigation chart
gives the height of an object, by sighting on it and counting the number of MILs, you can determine how far
away it is. Here are the two formulas (note the use of metric units):
1) To measure distance when the height is known:
Object height (m)
Scale Reading (mils)
2) To measure object height when the distance is known:
Distance (m) x Scale Reading (mils)
1000
Example:
You know the height of a lighthouse is 85 ft / 26 m. The top of
the lighthouse comes up to the 60 mil mark on the reticle. So,
26/60=0.43. Multiplying that by 1000 gives you a distance of
433.3 meters (about 1/4 mile) from the lighthouse.
6
x 1000 m = Distance in meters
= Object height in meters
Ranging
Reticle