Visibility of Luna and Lunar Crescent

moden (Reingold & Dschowttz, 2OO1). A numbor otorhor rutnors navo contrtbur.d
on rcrai€d tssle. (atr.3hk, 1993, y.s, 1997, Odeh, 2oo4 etc.). A. ,ghr from rhe
beginnlng the c6tenda6 rE 6s$ctated wirh th. cyct€s ot rh€ heavens, rhe eme
.re Evi*ed atongvilh tno a$ociated catendaB in the nen anbb oi thts chapter
wlth speclal emphasts on the tst.mic Lunar catendai
Durlng the mod€rn rims tt wa3 onty in rhe tasl quaner of the 19rh century
lh.l weslem askorom66 stangd erpto,ing the pbblem of ea l6sr sigh trg o, new
lunar the tast antcte is a bnot luruoy 'oscent.
of lrorature that delcribed and
ttweropod vaious c,ire.t. o, models for lhe $tulto. ot probt€m ot d.t.rmining th€
day or lh€ fl6t vlslblltty ot tun.r crescont at any ptac€ on th6 Elobe du nE 2olh
Ll
PARAMETERS FOR VISIlIILITY OF NEW LUNAR
CRf,SCDNT
The Moon. the ody natunt sateuirc oflhe Eanh. is eoiog ound lhe [anh h an
orbit thot is a hiShly iftgrlar ellipe Thc i resutariries in lhe pd$ of rhe M@n a€ duc lo
llrc facl Et its norion is govemed by not onty tbe gEln ional pu oflhe Eanh. bur is
also aaf.clcd by toan) of rhe ncishholiing cetestial objecN (Danby, 1992). \\,nh r
Hadh s varying dhr&ce fron lhc Sun, thc e,Iecioa $e Sun,s gnvnodonat pull v,rics
srbstmti ly snh rheElarile posnionsofthe Eanh and the Moon. Moreov.!,lhe afcors
orthe confisur.lion oflheshole Sotrsrslem (losirions ofa| lhe major ptMcrs a.d $c
major ar.rcid9 on rhc morion oflhe Moon is oor nesligibte, Thus, accoding ro rhc
''Eplremirid€s Lun,irs Prisiemcs,, popularly tnoh d Chapont,s tuM tho,y ELp,
2000/82 (Chapronl-Touze & Chapronr. t 983, Cluprcnr-Touzc & Chaprcnt, t99l), tor lhe
b.sl possible plecision iD te lonSirude, hdnde md lhe disrance (bclsen lhc Mon and
the Eonh), dere aE equired as nany as 15i227 p€riodic r€rms. On lbe othf hand, for
dcteminhg 6e position ofrhe Sun b r simile d.8E of acc@cy one rqdB 2,425
periodic rems in vicw olrhe ,Variarions S.culair€s des Orbnes plandaiet, rhe Fiench
pr.netary th€ory lnoM as VSOP87 (B&raSnon & Fl!Bo!, t988, Meus' 1998). The