Visibility of Luna and Lunar Crescent

Chapter No. 4
PHYSICAL MODEIS & THEIR EVOLUTION
AI thblclh rhe twen €rh .entury and Inro $e ie€nry ftrst century a tot o,
wotk h.s been done on vanous aspects ot the probtefr of vtstli ty ot new tqnaf
ce$€.t. th€se other t$u65 In.tud6 (t) ton€th o, tunar cr6sc6hi {Danjon 1932.
1936, yas 19a3b, 1garta, McNa y, schaeisr, 199ft, McN.xy, 19a3, sotran, 2005,
Qu6hl & khan, 2006, .rc,) (ia) the mintmun o, timtthg €tonga(on of n6w vistbr.
lunar cfescenr (Danjon, 1932, ras 19a3b 6tc,), (thr $asohat varaa ons In the
€anbt vjstblliry oi .ew luna,.r.scenr (llyas, 19A5, Crrdwel & !an€y, 2OOO erc.).
On€ ot rhe mosr stgntfi.ant or these and olher sffons B rhe hrroduction of rhe
-|rrohattomt
Lmr D6te Ltne" or |LDL (contras0na rh. |nr.ma onat date ltno
(solar)) by lltas (ltyas! 19A6b). Thoogh the td6a h.s n€ve, D.en !s6d h pbctic€ of
lunar cat€.daE but rhe !€me has b€en erten.ivety usoc |n lonrare (ror insrance
luooioat by t{an4r lnd A@urat. llmo by Odeh) as a gu|d€ for the rcgtons of
vlslblllty or i.vtltbllty oi ths n6w l!..f cr€s6nt, How€ver, In thi. wort the main
emphasts ls on th6 modets rhat deat wlrh rh€ probt.m o, eaniest vlsrbi ry of new
lun.r cesco.t so that other tssues 6r€ nor constdered.
The ri6t asr@phlstc.t modet fo, ervtng thls polreh was rhat o, aruin
{8tu1n, 1977),Ihis kas ba$d on tho av.rage bdgttness hodetrorru tltoon, rh6
averaSo b.tghtnoss ot the twlighr sty and lhe theory or extlnction ((ooman, 1952,
B6mporad, 1904, Sted€ntopf, 1940). Sruh was ,bo rhe rid jn modern rimes ro
exprott lho v.rtaflons of tunrr s.miii.meter wlth rhe Eaft]vtoon dlsrance,
Afiotu€rds, app€ared lh6 .xtenstve u!6 o,lho phFlca .nd scionce ot vtslblity by
Schaetor donng rh6 t6st quarte, o, th€ twe. eth @ ury Gchaefrer, 19s6, gaaa,
19aab, 1989, 1990, 1991., 1993) ba$d o. vrdous racto6 ike armosohoric