Visibility of Luna and Lunar Crescent

AII the* fout deviati.S cdes ae photogdphically Ecoded dd have the ledi
posibiliry o| obseNational ercs. Out of |he t€s1 of th. €ight ca*s anothcr six @
plDlosnphic. Thc rccords due lo Sch&fq de lhc only cag 0tar "ob$nation.l lcngrh
of .ew lunr cE$ent is @nMed ils Eladon wift elo.Salion mul nol bc sneln 6
shoq in flsuE 5. L2 as w€u 6 table 5. l2 (or nsurc 5. L7).
It is tunher nored $ar rhe rool mear square erot calculated foi lhe lhree
conputational frdhods (Ouls, Sultmt and McNally t it n found $at Suhan s melhod
h6 rhe led( cror (4.76 degr€et follosd by McNally's thal ha m .mr of 6 16 decrs
dd our model hd an eror of ? 22 degR' The najo. difer€nce h€lwen our model dd
rhN Sulbn's dd McNaUy s is that olr nodel 8iv* coosislmtlv hisher valucs ol the
lenefi oi crc$ent, wliets $e orner lNo nodcls havc bolh posidve lnd n.8flive emn
Th€functionalrel.tionbet*eenelongationardlhecrcscenll€nglhissinlilorinolrtuodcl
aDd $ar due to Srll.n s. bul lhe oneerhibi(ed by McNally's model is m.rkedly difitrcnl
McNally s mod.l is Sivins betre esuhs for larser elo.gaion but a3 $. clo.Sation
becond snaller the emr given by McNally s nod€l beconcs leser and ltrger
Tdhl. No t.1-2tth:.^r"la r'!h,lak.t L?ngths o[CrctehB
t87