Visibility of Luna and Lunar Crescent

Chapter No. I
INTRODUCTION
Slnce rhe anclent ttmes rh. 6preaEn@ ot n€w tunar cr6cent marked lhe
beginningofa new monlh. With the d€votopment ot ctv zarions org.ntrtng lme tor
e(ended pe ods lnto weeks, months snd teaE, the tlnar phase cyctes tead to tho
evolutio. ot calendaB. lh6refore the pobtem ot dotermining the day of tiFt
sEhtingol n€w crescent moon arlbcted hlman betngr tt Invotves con stderatio n or
a nuhber of astronomlcat es wett as other facto6. On the orher hand th6 probtem
ol obserylng the new tunar cres.6nt at an eaniesr posstbte momenl ts chalenging
for bolh amateuE and professtonat .5tonome6. Th6 .st,onomtcat paEmetets on
whlch thesolution olthlsprobtem ts bas6d are b eflydtscussed in the ftsl .iicte ot
The circudstarces and parameteE assciated with th€ problem of sighting
new runar cresce.t Sreatty vrry wirh th€ v.rytng post o. or obseder on rhe globe.
The atfecls ot the geographicat tocation on the probtem ls briefiy discussed in rhe
next 6rtlcle. Atempts to determlne crle a tor the delermintngthe flrst ltslbitity ot
new runar c@scenr ai..y ptac€ rpp.ared as €any as the Babytonian ers (Faroohier
al, 1999, Bruin, 197?, tty.s, 19946). Signncanr adrances were made by Mustims
and AEbs during medlevgt perlod. A brt€l nccount ot thes6 ancient aid medieval
effons b discu$ed ln thtd.dtcte ofthts chapter.
Srnce anliqolty changing phas6 o, the Moon and a comptete cyct€ or rhese
vrriallorc has been ured a3 meansot k€€ptnEaccount ofcatendaG. |yas hasgiven
a delailed accounr of the history of ihe sci€nce of lunar crescent vlstblity and the
lslahic Calenda. (rryas, 1994.), Dogger h6 di$ussed lhe history and rhe
deveropn. of calenda6 (oo€get,1992), Fetngold &o€rshowitz hav. presenred a
(omparEllvesludy or morethan rw€nry catendaG or vsrtous (ypes both sncien, a;d