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

A technique for improving the → resolving power of a telescope by controlling the shape of the main mirror at a relatively slow rate. The → image quality is optimized automatically through constant adjustments by in-built corrective → actuators operating at fairly low temporal frequency ~0.05 Hz or less. → adaptive optics.

→ active; → optics.

A technique for improving the → image quality of a telescope against → atmospheric turbulence in which image distortions are compensated by high-speed changes in the shape of a small, thin mirror. → wavefront; → wavefront distortion; → wavefront correction; → Strehl ratio; → tip-tilt mirror, → Shack-Hartmann wavefront sensor, → active optics.

→ adaptive; → optics.

An → adaptive optics instrument used on the → European Southern Observatory (ESO) 3.6-m telescope at La Silla. It was an upgraded version of COME-ON-PLUS, the → Very Large Telescope (VLT) adaptive optics prototype. It had 52 → actuators and performed corrections of the mirror 200 times per second. The reference → wavefront was sensed in the → visible. The observation was done in the → near-infrared (1-5 μm).

→ adaptive; → optics; → near-infrared; → system.

An → optical system that uses → adaptive optics.

→ adaptive; → optics; → system.

1) To choose or take as one's own; make one's own by selection or assent.
2) To take and rear (the child of other parents) as one's own child, specifically by a formal legal act.
3) To vote to accept (Dictionary.com).

M.E., from M.Fr. adopter, from L. adoptare, from → ad- + optare, → opt.

Baroptidan, on the model of bargozidan "to choose," from bar- "on, up, upon, in," → on-, + optidan, → opt.

The act of adopting. The state of being adopted.

→ adopt; → -tion.

Of or involving adoption. Acquired or related by adoption.

→ adopt; → -ive.

Light that is reflected from a curved surface mirror.

→ catoprtics; → light.

An optical system in which the light is reflected only.

→ catoprtics; → system.

The area of → optics which treats of the laws and properties of light reflected from reflective surfaces.

From Gk. katoptrikos, from katoptron "mirror" (from kat-, → cata-, + op- "to see," → optics, + -tron suffix of instruments) + -ikos, → -ics.

Bâztâbik, from bâztâb, → reflection, + -ik, → -ics.

A branch of optics that uses coherent radiation to produce holographic three-dimensional images of objects.

→ coherent; → optics.

A unit of optical measurement that expresses the refractive power of a lens or prism. In a lens or lens system, it is the reciprocal of the focal length in meters.

L. dioptra, from Gk. di-, variant of dia- "passing through, thoroughly, completely" + op- (for opsesthai "to see") + -tra noun suffix of means.

Dioptr loanword from Fr.

An instrument used in antiquity to measure the apparent diameter of the Sun and the Moon. It was a rod with a scale, a sighting hole at one end, and a disk that could be moved along the rod to exactly obscure the Sun or Moon. The Sun was observed directly with the naked eye at sunrise or sunset in order to prevent eye damage. Aristarchus (c.310-230 B.C.), Archimedes (c. 290-212 B.C.), Hipparchus (died after 127 B.C.), and Ptolemy (c.100-170 A.D.) used the dioptra. The instrument could also serve for measurement of angles, land levelling, surveying, and construction of aqueducts and tunnels.

→ diopter.

An → adaptive optics system with high-contrast imaging and spectroscopic capabilities. Extreme adaptive optics systems enable the detection of faint objects (e.g., → exoplanets) close to bright sources that would otherwise overwhelm them. This is accomplished both by increasing the peak intensity of point-source images and by removing light scattered by the atmosphere and the telescope optics into the → seeing disk.

→ extreme; → adaptive; → optics.

A branch of physics that deals with reflection and refraction of rays of light without reference to the wave or physical nature of light.

→ geometric; → optics.

Initial name given to → Vera C. Rubin Observatory.

→ large; → synoptic; → survey; → telescope.

An → optical system in which the → optical axis of the → aperture is not coincident with the mechanical center of the aperture.

→ off; → axis; → optical; → system.

To make a choice; choose (usually followed by for).

From Fr. opter "to choose," from L. optare "to choose, desire, wish for," from L. optare "to desire, choose," from PIE root *op- "to choose, prefer."

Optidan, from L. optare, as above.

Of, relating to, or constituting a verbal mood that is expressive of wish or desire.

From M.Fr. optatif, from L. optativus, from optatus, p.p. of optare, → opt, + -ivus, → -ive.

Optâné, optmand, from opt present stem of optidan, → opt, + adj. suffixes -âné, -mand. -yi.

1) Of or pertaining to the eye or sight.
2) Same as → optical.

From M.Fr. optique, from M.L. opticus "of sight or seeing," from Gk. optikos "of or having to do with sight," from optos "seen, visible," from op-, root of opsesthai "be going to see," related to ops "eye," from PIE *ok^w- "eye/see."

1) Nuri, nurik, from nur, → light + -i, -ik adj. suffix → -ic.
2) Didgâni, related to didgân "eyes," plural of didé "eye; seen," from didan "to see" (Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen").