differential image motion monitor (DIMM)
pahregar-e jonbeš-e degarsâneyi-ye vine, ~ ~ ~ tasvir
Fr.: moniteur de mouvements d'images différentiels, moniteur seeing
A device that is commonly used to measure the → seeing at optical astronomical sites. The DIMM delivers an estimate of the → Fried parameter based on measuring the variance of the differential image motion in two small apertures, usually cut out in a single larger telescope pupil by a mask. The DIMM concept was introduced by Stock & Keller (1960, in Stars and Stellar Systems, Vol. 1, ed. G. P. Kuiper & B. M. Middlehurst, p. 138), whereas its modern implementation was first described by Sarazin & Roddier (1990, A&A 227, 294).
1) pahridan; 2) pahregar
Fr.: 1) contrôler; 2) moniteur, écran de contrôle
1) (v.) To watch closely or evaluate something on a constant or regular basis.
From L. monitor "one who reminds, admonishes, or checks," from monere "to remind, warn, advise," related to memini "I remember, I am mindful of," mens "mind," from PIE base *men- "to think;" Pers. cognates under → idea.
Pahregar "watch, guard,"
agent noun from pahré (Dehxodâ) "watch, guarding," from Mid.Pers.
pahr, pahrag "guard;" Av. pāθra.vant "guard, watchman," from
Av. pā- "to protect," pāti "guards,"
nipā(y)- (with → ni-)
"to watch, observe, guard,"
nipātar- "protector, watcher," nipāθri- "protectress;"
cf. Skt. pā- "to protect, keep," tanû.pā- "protecting
the body," paś.pā- "shepherd;" Gk. poma "lid, cover,"
poimen "shepherd;" L. pascere "to put out to graze," pastor
"shepherd;" Lith. piemuo "shepherd;" PIE base *pā- "to protect, feed."
Fr.: moniteur de seeing