Visibility of Luna and Lunar Crescent

(escenr $idr varying wea$cr condilions whercas Bruin s nodel h based on aleragd
brishlncssofsky dd rhe FullMooo.
As clain€d by Sctaefd th€ brightn s modcls @v b€ in mt by a mucb a 2elo
still our Drodcl yielded be .t resul$ s comPsed 1o tho* due to Bdin ad YalloP as lar
as rhe posirive observatiohs arc conemed lt is lroped rhat wilh beller models of skv
brighhcss slill beiterclitrion ior fiGt !isibility ofnew lund descent can be delclopcd
sonE of$e lpplicarions of {he cnbda of.atliesr visibililv of ne\f llod 'rc$ctrt
havc becn considered in $is $ork The fid ond $c mosl impoddnt applicalion lre ro
d€(eaniDc Nhcn tbe new lunar cresceht would b€ visible ar soDe ldalion on lhe elobc on
rhe elennrg aicr rh€ oonjundion Anolher ar.a ol appl'calion is lo deduce d
''obscNnrioMl lunar c.lcndii- tor a 'eeion
Yct anofier aBa ol apdic'tion \e hn\c
e\ploreJ '.roJdrnrine
lhe lcnslh ofne\ ldDrr crcs(nr
t( !1ay be recalled (hal lhe liret appcardnce of new llnn crcscctrt nrarlis r
b€sinning ola new monrh in obsenalional lunor calendarq rhere
'ril'ria
and models drc
siBnillcor br calendatical Purposs whefier 'n aduul o6€n:ri'nol lunar calendai likc
rlc hliNic Lunar calendar' ulilizrs tb6e cril.da for a!6nging its cltndar ot Dol lhcsc
cLirdia ptuvidcs a guidancc Ibr bolb tesing an tvidcnce oi oescenl sightirrg bv connnon
peotlcdnd tacingdowndtdtrlesofac.l€ndar inhhrorv{herc approprirle dates arc rol
\€ll Ncordcd. rhus $c frtin ililt of the pcdicrio! crileria $e carliesr visibiln)' ol
' 'or
n€rv crc$.m is lo egntalc tnc obsefl.lional lunar calendtr dd tcsrifv lh€ clainrs ol
risibility of ne\' lunar crcsccm
Although fiIsl ordc! iPporirutions like Arnh'neLic Lunar Calendtr tlrat di'
based on lle conc€pr of Le.p Yea$ md rne a!.rage oorion o' rnc Moon havt be'n nr lse
Muslims h.vc been follosin8 acoal sighing of cresc€DLs l@l lor lhe monlhs ol
'r
i6rii8 (R.maan) $d pilsinage (zil hajjah) Thc calendars if bled o' a PEdicrion
oir*ion like tbat of Yallop or dre ohe dcveloped in this work arc $e cLosest lo rnc
obervarional calendd Conpan$n of rhese criteiia wiih lhc actual obFNsdonll
201