Plate scale

 ( Astrophotography ) 

The plate scale of a telescope connects the angular separation of an object with the linear separation of its image at the focal plane.

If focal length is measured in millimeters, the plate scale in radians per millimeter is given by angular separation , and the linear separation of the image at the focal plane , or by simply the focal length : $$p\; =\backslash frac\{\backslash theta\}\{s\}\; =\backslash frac\{1\}\{f\}\backslash \; ,$$ since $$s\; =f\; \backslash theta\backslash \; .$$

Plate scale is usually expressed in arcseconds per millimeter: $$p\; \backslash approx\backslash frac\{206265\}\{f\},$$ where is in , or expressed in arcseconds per pixel after further division through the Pixel density.

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Plate scale on JWST FGS/NIRISS /ref>

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See also

• Photographic plate

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Notes

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