Visibility of Luna and Lunar Crescent

visibility curve. So fd th. mod€l due to Y.llop b lhe morl oulhfltic and dep€ndable
slronohi€l cri|€na for cxper.d ali.sl visibilily ol new l$m ccenl. The modct due
10 Yallop isa smi-empirical model based on $e lheor€dcal considedions of Bruin and
.ftiteriononthebasisofabusicd.tadeduccdfonBrui. svisibilitycurvcs.
Tnc mosr extctuive r.atm6t of rhe physicat dp<l3 eciared wit th. pDblm
is due lo SchNld (schacftr, 1988(a). I988(b)) who has considercd tlt Poblem of
bidtn€ss contEl isoroudt. He ale rcali2ca jnpoitance ofthe physiolosicol aspecrs
like $e abilirt oahunan.yc ro eoe th. limili4 co.kast. Soh&reas nodel is ! pdrel!
lhoerical n\odcl. Recntlt Odeb (2004) hls claim€d to harc dev€loPed a nc* ctnenon
for the.arli.sr vnibihr oineq luffi cle$ent bur his cinqion isjust ano$o lom ol
Olh.r authoE have contributed on cloted nsues (Ashbrcot, lt7!a. I97lb.
Cald$ell a|]d t-anct.2000. I0loohi c. al.. l99lt. lltas. l98l!. l98lb. l9li'll, l93lb
1985. 1988. 199,1r. 1994b, M.N5l1r_. 1983, Schaefler, 1988r. 1988b, 1996- Sch!{ffcr er'
!l 1991, Suhan.2005, Queshi& Khan.2005.2007 elc) ln fih \ork. €och ancior Md
nodciD halhc'hadcrl mod.l aor detmnrnB $e day ofltu fi6l siehing ofne* lunar
cEsce h cNploied A comparative study oi lhes nodch is canicd out and each
crncrion is rrlsfornrd in(o a one pdamcter visibilily crilcriotr like th.t duc lo Yall.p
Th€ resulrinS cllendaricdl imp licariohs .rc aho cxplorcd
lr hos been poinlcd our in lhe bLSinnine of $e chlpld thar the prublem ol
determinihg $e dat when the nes luar (esc€nl $onld bc \isible has its calcndarical
inplicarion. The earli$t siShtine of new luMr calcnde is ale a cballmging l.st lor bolh
maleuB and Dlolessional ashhoncB. In \ic$ olrhis rhc chafler hd niehli8hled:
Paranere6 on which visibiliry of new lunar cescent depends
Thc cfons ofrhe 6tro&meB iD lhc lncie.l and lhe n di€ul tlnes.
22