Visibility of Luna and Lunar Crescent

cdly 2di cenlury astononeB. Thc significanr findin8 of the chaprer h $al borh lhc
simpk Babylonian c ldion and rhe Lunar RipeNss IEw a!€ morc successfutin tcrms of
thcn co.sistnct Nnh rn. posirile sghrings dords in comparison b fie hodeh
ddllopcd in th€ fiBr haliof2(]ucenrury Ascroa46Sobsonationsisuscdforleslinslll
modcls in thil {ork. nr.r incldc obseNations collccted since thc latcrhrlaof l9'i cemtry
ln conparison lo lh. empnical odcls nrd to prcdicr lhe visibilil) of lhe nc$
lu. cr€*enl iill rhe lid balfot $e l$ndelh c€nlur)- lhe 6od.ls dcleloped on rhe
b6is of phFical rheoriN of sl! brighhess and extincrion trc cxPloEd nr thc lol'nh
.[dfl*. i he* models incl"de l[o$ d.ralotrd by Bun aM sclDrftr scpamLl]. Btoin
bed his mddrl on lhe rveige briehhcss of lhc lull Mdon and lhe lriligh slv.
Schacfeis model calculales th. octual lin ins mdgnitud. oaihc skj and $c ntgnnud.
of rhc cftsdrl id tcsls a vkibilitt cldinr on rh. bnsis ol nugnirrd. coniGt and rs
difte{nr ir nrtuLc tio$ allother nodeh An.ra bdel deeriprion of Bruin s modcl ihe
scmi-cnrpiricrLnDdel olYillot is discu$ed in d{(.i1. Nhich isconsiderud to be rlt nDn
Nnrflchcnsi\c !trd aldrcnlic nrodcl. Y{llop dcducdd his busic d.h lrotrr lr ns
\isibilnJ curvcs. On nre brsis of Schadfcas tcchliqocs qc hd\c rlconsLruorcd Inui s
model rnd pruduccd lcw visibililt crNes Md. ncs scmi-enrpnicll nodel lbr rhe
\isibilnJ oanc$ llnar crcscenl fte delclopNcnl ofllris n.w nrodel is one oith( Naior
{chicve.nEoflhis$ort.AllIhemodelsarclestddnthssamcdaldselasisusedinrhe
!rc\ious chaplcr lhc nc$ nrodcldc\cloPLd in lhis qorl is found lo be rhe bcst aDonssl
rlB nlodcflr dr) dels in rcnrs olils cdnsnlcnct Nilh lh. nunrb.r olposirilc sishrinSs
in lhc d asduscd A compali$n ofsuccess oaqch nodcl h aho disNsed in tlns
Al $e end of $c founn chapler a emtce} is iEmed b *di dle tulhcnticirt of a
claim of siehlins or ne\ cte$e on lhe bsis of a rmi_enpnical modcl and th'
Nasnitudc conlras oodel -fhe sisnific.nce of such a stat€s) hN b€cn highlignred 4s
rherc ae found d nuob.r of authenric ne\r cG$c risibihv claims thlt are nol
coosisienr wnh a *ni-cmpilical nodel tn lhcse ces a semi'copnical nodel des not