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

An optical, alkali-lime glass which is harder than → flint glass, and has a lower → index of refraction and lower → dispersion. It is used in the production of → compound lenses.

Such named because of the crown-like shape given to the blank after the process of blowing the glass; M.E. coroune, from O.Fr. corone, from L. corona "crown," originally "wreath, garland;" cf. Gk. korone "anything curved, kind of crown;" → glass.

A device consisting of a pair of glass or plastic lenses worn in a frame in front of the eyes to help correct imperfect vision or protect the eyes from light, dust, and the like. Also called glasses, spectacles.

→ eye; → glass.

Eynak, probably related to âyené "mirror," âbginé "glass" (Mid.Pers. êwênag "mirror," from *âdênak, from Proto-Iranian *ādayanaka-, from prefix ā- + the root of Av. dā(y)- "to see," didāti "sees" (cf. Mod.Pers. didan "to see," Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen") + suffix -ak). Other obsolete Pers. equivalents for eyeglasses are cešm-e farangi "Frank/European eye" and âyene-ye farangi "Frank/European glass." And it seems that the oldest mention of eyeglasses in Pers. is by the poet Jâmi (1414-1492), who calls it farangi šišé "Frank/European glass." These paradigms support the relation between eynak and âyené. As for the more recent term sam'ak "hearing aid," which is invoked to relate eynak to eyn (Ar. 'ayn "eye"), it may have been coined on the model of eynak supposing that eyn means "eye."

A basic type of optical glass containing lead oxide and a smaller amount of potassium, characterized by its brilliance, clarity, and durability. It has a high → dispersion relative to its → refractive index, as compared to, e.g. → crown glass. Flint glass is sometimes used as the diverging lens component of an → achromatic lens. It is also used in the manufacture of table glassware.

Flint, because it was originally made of calcined flints, from M.E., O.E.; cf. M.Du. vlint, O.H.G. flins, Dan. flint; Gk. plinthos "brick, tile."

A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or phosphoric oxides.

From O.E. glæs, from W.Gmc. *glasam (M.Du. glas, Ger. Glas), from PIE base *gel-/*ghel- "to shine, glitter."

Šišé "glass;" Mid.Pers. šišag.

A mass of glass ready to be shaped into a telescope mirror. Same as → glass disk.

→ glass; blank, from O.Fr. blanc "white, shining," from Frank. *blank "white, gleaming," of W.Gmc. origin (cf. O.E. blanca "white horse"), from P.Gmc. *blangkaz, from PIE *bhleg- "to shine."

Gerdé, → disk; šišé→ glass.

Same as glass blank.

→ glass; → disk.

A filter used in → broad-band photometry. The → bandwidth ranges usually between 30 and 100 nm.

→ glass; → filter.

A device for measuring time; it consists of a glass container having two compartments from the uppermost of which a quantity of sand runs in an hour into the lower one through a narrow tube.

Hour glass, from → hour + → glass.

Sâat-e šeni, from sâat, → hour + šeni, adj. of šen "sand."

A lens or lens system that produces an enlarged virtual image of an object placed near its front focal point. According to Enoch (1998, SPIE vol. 3299, p. 424), the earliest lenses identified are from the IV/V Dynasties of Egypt, dating back to about 4,500 years ago (e.g., the eyes of the Louvre statue Le scribe accroupi and other examples located in the Cairo Museum). For more information see → burning sphere.

Magnifying, verbal adj. of → magnify; → glass.

Zarrebin, from zarré "a minute thing," → particle, + bin "seer; to see" (present stem of didan; Mid.Pers. wyn-; O.Pers. vain- "to see;" Av. vaēn- "to see;" Skt. veda "I know;" Gk. oida "I know," idein "to see;" L. videre "to see;" PIE base *weid- "to know, to see").

The → lens or lenses in the → object end of the body tube of a → microscope, by means of which the rays coming from the object examined are brought to a focus. Same as → objective. An old term for the → objective lens of a → refracting telescope.

→ object; → glass.