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

Physiological process whereby the eye adjusts its sensitivity for different levels of illumination.

→ adaptation, → eye.

A galaxy at a → redshift of z = 2.3259 lying behind a massive → cluster of galaxies and magnified by the → lensing effect of the cluster. It was first discovered in → submillimeter waves. The lensing cluster lies at a redshift z > 1.5 causing an → amplification factor for the background galaxy of 32 (A. M. Swinbank et al. 2010, Nature 464, 733).

→ cosmic; eyelash, from → eye + lash, from M.E. lashe (n.) lashen (v.) "to blow, stroke." Such called because of its narrow and elongated shape.

Možé "eyelash," from Mid.Pers. mec "eyelash," mecitan "to blink;" cf. Skt. mes "to open the eyes;" O.C.S. po-mežiti "to close the eyes;" keyhâni, → cosmic.

The organ of vision that detects light.

O.E. ege (Mercian), eage (W. Saxon), from P.Gmc. *augon, from PIE *ok^w- "to see;" cf. Av. aši- "(both) eyes;" Skt. áksi- "eye;" Gk. osse "(both) eyes;" Goth. augo; O.C.S. oko; Lith. akis; L. oculus; Arm. ac-kh "eye."

Cašm, from Mid.Pers. cašm, Av. cašman- "eye," ākas- "to look," from prefix ā- + Proto-Iranian *kas- "to look, appear," cf. Skt. cáksus- "seeing."

The distance between the eyepiece of a telescope and the location of the exit pupil. This is where the observer's eye should be positioned to see the entire field of view of the eyepiece. Also termed eye distance.

→ eye; relief, from M.E. relef, from O.Fr. relief "assistance," from relever "to raise," from L. relevare "to raise, alleviate," from re- intensive prefix, + levare "to lift up, lighten."

Cašm nehâd "eye position," from cašm, → eye, + nehâd "position, placing, posture," contracted form of nehâdan "to place, put;" Mid.Pers. nihâtan; Av. ni- "down; into," → ni-, + dā- "to put; to establish; to give," dadāiti "he gives;" cf. Skt. dadāti "he gives;" Gk. didomi "I give;" L. do "I give;" PIE base *do- "to give."

The necessary precautions that must be taken in order to avoid damaging the eyes when watching a → solar eclipse. The only time that the Sun can be viewed safely with the naked eye is during a → total eclipse, when the Moon completely covers the disk of the Sun. It is never safe to look at a → partial eclipse or → annular eclipse, or the partial phases of a total solar eclipse, without the proper equipment and techniques. Even when 99% of the Sun's surface (the → photosphere) is obscured during the partial phases of a solar eclipse, the remaining crescent Sun is still intense enough to cause permanent retinal damage, especially when viewed through binoculars or other optical aids (F. Espenak, NASA).

→ eye; safety, M.E. sauvete, from O.Fr. salvetet, from M.L. salvitatem "safety," from L. salvus, cognate with Pers. har "all, each, every," → holo-.

Gazand "damage, injury," Mid.Pers. wizend, ultimately from *ui-jan-, from *ui- "apart, away from," → expand, + *jan- "to beat, strike," cf. Pers. zan-, zadan "to beat, strike," → beat; cašm, → eye
Zilegi, → security.

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 → lens system, also known as an → ocular, used to → magnify the → image formed by the → objective of a → telescope.

→ eye; → piece.

Cašmi "ocular," adj. of cašm→ eye + -i adj. suffix.

The first achromatic eyepiece consisting of a convex lens and a plano-convex lens. The convex surfaces are turned toward one another.

Named after the inventor Carl Kellner (1826-1855), a German engineer and optician; → eyepiece

Two → interacting galaxies, NGC 4438 and NGC 4435, located in → Markarian's chain of galaxies in the → Virgo cluster of galaxies. About 50 million → light-years away, the two galaxies are about 100,000 light-years apart. Gravitational → tidal forces from the → close encounter have ripped away at their stars, gas, and dust. The more massive NGC 4438 kept much of the material ripped out in the collision, while material from the smaller NGC 4435 was more easily lost.

→ Markarian galaxy; → eye.

The qualifier of an eye which is not assisted by any optical device, except for eyeglasses. Same as → unaided eye.

→ naked; → eye.

A star visible without a telescope. In principle, stars down to about sixth magnitude are visible to the naked eye under ideal conditions, but this depends on the individual, the location, and the conditions of the observation.

→ naked; → eye; → star.

A telescopic eyepiece that produces a wide field of view (between 40° and 50°). The eyepiece consists of a single element lens that is normally plano-convex, and a cemented triplet that is usually symmetrical.

→ orthoscopic; → eyepiece.

An eyepiece consisting of two planoconvex lenses of the same focal length, placed with the convex sides facing each other and with a separation between the lenses of about two-thirds of the focal length of each.

Named after Jesse Ramsden (1735-1800), English maker of astronomical instruments; → eyepiece.

The eye unassisted by an optical instrument, except for eyeglasses. Same as → naked eye.

→ un- + aided, from aid, M.E. ayde, from O.Fr. aidier, from L. adjutare, frequentative of adjuvare "to give help to," from → ad- "to" + juvare "to help;" → eye.

Cašm, → eye; biyâvar "without help," from bi- "without" + yâvar, variant yâr "helper; companion" (Mid.Pers. hayyâr "helper," hayyârêh "help, aid, assistance," Proto-Iranian *adyāva-bara-, cf. Av. aidū- "helpful, useful"); berehné, → naked.