An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) Having a thin cutting edge or a fine point.
2) Of an image, clearly defined; distinct. → sharp image.

M.E.; O.E. scearp "cutting, keen, sharp;" cf. Du. scherp, Ger. scharf "sharp;" PIE base *(s)ker- "to cut."

Tiz "sharp," variants tež, tej, tij, tiq, tik, tig; Mid.Pers. tigr, têz, têž "sharp;" O.Pers. tigra- "pointed," tigra.xauda- "pointed helmet (epithet of Scythians);" Av. tiγra- "pointed," tiγray- "arrow," tiži.arštay- "with the pointed spear;" cf. Skt. tikta- "sharp, pungent, bitter," tejas- "sharpness, edge, point or top of a flame;" PIE base *st(e)ig- "to stick; pointed." Cognates in other IE languages: Gk. stizein "to prick, puncture," stigma "mark made by a pointed instrument;" L. in-stigare "to goad;" O.H.G. stehhan; Ger. stechen "to stab, prick;" Du. stecken; O.E. sticca "rod, twig, spoon;" E. stick.

An image with clear and distinct details. Opposite of → blurred image.

→ sharp; → image.

1) To make sharp or sharper.
2) To increase the spatial resolution or the clearness of an image; same as → deblur; → deconvolve.

Verbal form of → sharp.

Tigidan "to sharpen," verbal form of tig→ sharp.

A list of 313 individual → H II regions in the → northern → Milky Way (north of declination -27°). It includes several → planetary nebulae, → supernova remnants, and → reflection nebulae. The first edition (Sh-1) was published in 1953 with 142 objects and second and final version (Sh-2) was published in 1959. The catalog categorizes the H II regions in terms of several parameters, such as diameter, form (circular, elliptical, irregular), structure (amorphous/filamentary), brightness, and number of associated stars, which are further discussed in terms of their spectral classes.

Stewart Sharpless (1959) A Catalogue of H II Regions, ApJ Suppl. 4, 257; → catalog.

An image in which finer details are not visible. → blurred image

→ un-; → sharp image.

A process for amplifying fine details in a registered image. Generally speaking, the process consists of creating a mask which contains larger scale features of the image and then subtracting the mask from the initial image.

→ un-; → sharp; → masking.