The Chartwell collimation book 2426 is specifically printed with text and tables for surveyors use when undertaking collimation readings. This particular type of surveying is when a users has a line (of sight) extending from an instrument (sighting level, etc) along which distant objects or landmarks are seen, when viewed with the telescope or sighting devices. The 2426 is specifically printed up for this form of surveying, the book contains 80 leaves of 50% rag bond paper which is waterproof sewn into a side opening survey book.
