Micrometer eyepiece

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As a micrometer eyepiece which is the eyepiece of a measuring telescope designated obtained by an integrated microns (optical) measurements of subtle angular differences permitted.

In order to be suitable for such precision measurements, the optical and mechanical design of the eyepiece must allow the appropriate measuring unit to be attached to its focal plane . The micrometer replaces the usual cross-hairs or reticules . The first measuring eyepieces were constructed as early as the 17th century and further developed by astronomers such as Wilhelm Herschel or Friedrich Wilhelm Bessel , primarily for geographic location determination and for measuring star coordinates and double stars . They reached their technical perfection in the 19th century - among others by the companies Repsold and Starke & Kammerer - or (for special purposes) in the early 20th century. Finally, new types of micrometers and targeting methods were also stimulated by space travel and satellite geodesy .

The most important classical construction methods include the filament micrometer , the ring micrometer and the recording micrometer (impersonal micrometer) most commonly used in geodesy for the semi-automatic time determination with celestial bodies. With universal instruments (e.g. the DKM3 ) it can be rotated by 90 ° and thus also used for precise width determination according to Horrebow-Talcott .