Editing Reticle (section)

====Etched reticles====
[[Image:USGsight01.jpg|thumb |alt=The day and low-light reticles of the USG reflex sight used on the FN P90 / PS90 USG models |The day and low-light reticles of the integral [[reflex sight]] used on the [[FN P90]] / PS90 USG models]]

The first suggestion for etched glass reticles was made by [[Philippe de La Hire]] in 1700.<ref name="daumas">Maurice Daumas, ''Scientific Instruments of the Seventeenth and Eighteenth Centuries and Their Makers'', Portman Books, London 1989  {{ISBN|978-0-7134-0727-3}}</ref> His method was based on engraving the lines on a glass plate with a [[diamond]] point. Many modern crosshairs are actually [[Industrial etching|etch]]ed onto a thin plate of [[glass]], which allows a far greater latitude in shapes. Etched glass reticles can have ''floating'' elements, which do not cross the reticle; circles and dots are common, and some types of glass reticles have complex sections designed for use in [[Stadiametric rangefinding|range estimation]] and bullet drop and drift compensation (see [[external ballistics]]). A potential disadvantage of glass reticles is that the surface of the glass reflects some light (about 4% per surface on uncoated glass<ref>Richard Feynman, the red books</ref>) lessening transmission through the scope, although this light loss is near zero if the glass is multicoated (coating being the norm for all modern high quality optical products).