Does anybody know some formulas for using the TBT?

[CapnScurvy]

Given enough time, I'm suspecting the developers would have corrected their errors with the different resolutions. Also, they should have corrected their basic periscope "Field of View" size to allow for "real world" measurements and tools (like the Omnimeter) to be used in manual targeting.

These issues mean nothing to a player who uses the "auto targeting" option. The games auto targeting firing solution doesn't rely on the correct optical views and dimensions for providing an accurate measurement. However, when a player elects to use manual targeting, gleaning information on target bearing, range, speed, and AoB all require some use of the optics for an estimate in the firing solution.

The fact that the games field of view for the periscope is set at 36 degrees width (except for the 1280x1024 resolution, it's 38 degrees wide) but in real life, the periscope had only a 32 degree field of view. This makes a huge difference in measurement.

In real life, the periscopes telemeter divisions would have measured exactly 1 degree in width, making 32 divisions across the lens. It's a known fact that at 1000 yards distance, 1 degree of angle measures 52.3 feet wide (or tall). It's this basic knowledge that makes a formula like the one TorpX provided work. The trouble is the game doesn't play by the same real world dimensions. Grant you, you can count 32 divisions across the periscope lens (but its just eye candy). The game sets the field of view larger than it should when looking through the periscope, or has a number of sizes when looking through the TBT (depending on your game resolution). This makes using real world measurements, and dimensions worthless.

A mod that boasts it uses WWII ship dimensions for manual targeting is only fooling those that use it thinking its realistic play. Not until the optical views are set to real world sizes (for all resolutions) will real world height or lengths measure as expected. Optical Targeting Correction does this.