Visibility of Luna and Lunar Crescent

", =(^* - l- # -e4,:!.,'l) f "
v, =ltncv .lo.no - o.orn1o.tz1-
o.ooot uaz2\lto
tt =(^RCV - lrt.8311.- 6.3226tv + O]llgr2 -O.tOl8V3rttO
\t, -t5 + py rxtr+,pfl
v | = tARcv - \t2.4023 - 9.4818W + 3.9512W | - 05612Wt D t rc
vr=ARCL r !rc olscpaBlion - 21"
ln rhis {ork schactels modcl of dldritc bdshrn€$ is ale erPlond in t.ms of
nasnitud€ contrrst tnd thc dsllE aF in lsRD.nr $i$ his wo* (Schelet 1988.) -n'h
has b€en ehieved by iniplcmenrine lh. rshliqus d.r.loPed bv Schel.r and o$ets |o
ev.luarc sky brighhes (in tems of linninB mgnitud.) and r brishtocss ol lhe
cE$€nL Biglrness ofsky and that otcE$cnt dcp.nd heavilv on various ihosphenc
arsrs Amongsr ths lenpeBluE and clolivc humidnv arc lcpl \2riabl. in the
posram Hilalol in ord.r to exPlor posiblc condilions undd which claims of nlted ctc
v'sibihy m.y b. Br.d for dill€Ent condilions fhis lc.ds lo wh.t Ne h!v. r€mcd 4
Magdlude Conl6r (Amag _ maenilud. of Moon - skr's linritnl8 a!!iNdr) lf
mognnrd€ .onl6{ is n.galit n is lalour of cN*tnr visibililv o'tunvie Dol [or
cxftnEly crilical n.kcd cyc obserylrion ckn$ of Nw lunlr ce*cN lhe magnitude
co 6l lE ber dallaled nrinut lv h i5 tolnd $d $he of ftcs cdcs appear doublful
6 fie oasniude conrEst @ n.v.r in Lvout or cc*ent tisibililv cv'tr with hidlv
ex.8g.ra&d wath€r coDdnioB (v.ry tow clttivc humidnv and lcmPtdur) lor the
vhole dudtion of th. ooonsd-suet hg |inc. Using th. pogim Hilatol the tin$ have
ben evaluat d of(i) \$en $c nasnitud€ contGi is ndinn (ii) whcn rh' nasnilude
conlldr jnrl bccodc ialouEble for crcsa risibililv and (iii) {hen rhc masnirudc
conm was last in falolr or ccsenr vkibilirv Th.s. esulN .r. sinild $ whar is
de*ribed by. veniccl line ovr. liditing lisibili(y cur. ofBruin
201