Editing Reticle (section)

===Surveying and astronomy===
In older instruments, reticle crosshairs and stadia marks were made using threads taken from the [[Pupa#Cocoon|cocoon]] of the [[brown recluse spider]]. This very fine, strong spider silk makes for an excellent crosshair.<ref>Raymond Davis, Francis Foote, Joe Kelly, ''Surveying, Theory and Practice'', McGraw-Hill Book Company, 1966 LC 64-66263</ref><ref>Berenbaum, May R., ''Field Notes - Spin Control'', The Sciences, The New York Academy Of Sciences, September/October 1995</ref>

====Surveying====
In surveying, reticles are designed for specific uses. [[Dumpy level|Level]]s and [[theodolite]]s would have slightly different reticles. However, both may have features such as [[stadia mark]]s to allow distance measurements.

====Astronomy====
For astronomical uses, reticles could be simple crosshair designs or more elaborate designs for special purposes. Telescopes used for [[polar alignment]] could have a reticle that indicates the position of [[Polaris]] relative to the north celestial pole. Telescopes that are used for very precise measurements would have a [[filar micrometer]] as a reticle; this could be adjusted by the operator to measure angular distances between stars.

For aiming telescopes, [[reflex sight]]s are popular, often in conjunction with a small telescope with a crosshair reticle. They make aiming the telescope at an [[astronomical object]] easier.

The constellation [[Reticulum]] was designated to recognize the reticle and its contributions to astronomy.