Help wanted identify this document

[tradesecrets]

Hi all!
I am trying to identify what this document is and what it's used for.
My translation of the title from German doesn't seem to be making sense and I've never come across anything like this before.
Any ideas gratefully received.
Thanks
regards
A

[Gerdan]

It is a booklet for learning to estimate the distances in nature. You need it for an exactly shooting.

Gerdan

[tradesecrets]

Thanks Gerden!
once again your knowledge and help has been invaluable.
regards
Armen