Editing Pixel (section)

===Resolution of telescopes===
The pixel scale used in [[astronomy]] is the angular distance between two objects on the sky that fall one pixel apart on the detector (CCD or infrared chip). The scale {{math|''s''}} measured in [[radian]]s is the ratio of the pixel spacing {{math|''p''}} and [[focal length]] {{math|''f''}} of the preceding optics, {{math|''s'' {{=}} ''p / f''}}. (The focal length is the product of the [[F-number|focal ratio]] by the diameter of the associated lens or mirror.)

Because {{math|''s''}} is usually expressed in units of [[Arcsecond#Symbols and abbreviations|arcseconds]] per pixel, because 1 radian equals (180/π) × 3600 ≈ 206,265 arcseconds, and because focal lengths are often given in millimeters and pixel sizes in micrometers which yields another factor of 1,000, the formula is often quoted as {{math|''s'' {{=}} 206 ''p / f''}}.