Visibility of Luna and Lunar Crescent

for visibilny thftud rel.$ope. IlE vis'bility @lul6 @.mPty if rhe cjt*nt M not
Fen and co.tains V' in an apprcpriatc colLlm if the c!.sc.nl is sen. The esl of lhe
coluens oflhe nbl€ @n!in age ofMoon, LAC, ARCL, ARCV md DAZ. Th€ lasl file
@lmns arc ior the five models coroid.rcd in this chapler, The colllm h.dded A is for
This tabl€ shows $al out of 196 daims ofopdcally unaided sighlihSs oftbe nes
cresccnl there @ only ? cbes nol saisfyjn! lhc Babylonid critmon. HoEler, oul of
267 cdes vhen 6e cc*cnt wd nor e.n wilho any opftal aid ARCV + LAC is
gleate! thdn or 6qul to 22 deg@s i. l07.ses. Thus for pdniw siehli.8s rh. crit€no.
is foutrd lob€ successlul in 96.4% c.ses dd !frongsl lhe hegalive sigbdn$ ii su@ssful
in 59.92% css The sucess of€ model in desciibihg posilile sighlings alonc is tul a
cal success ofa nodel. Thc model is not suned seu if n is nol able to dc$tibe the
negalilc sishfng 6 wcll as ir d@s the p$ilive siShtings.
SOME SPHERICAL TRIGONOMfTRIC CONSIDERATIONS
Thh hd be.n m.ntioned e&lio rhal ior rhe ploblcm ofsiglting of new lund
crescenl $e orienlation ofthe ecliplic plays md inportant lole (article 1.2). Thecfoc, il
is inportant b rrisil lhe ne|hods thai lead lo lhe ddelhimion oflhe mgle lhal the
*lipric nlkes wilh the horircn al the tinc of snel on the *$em hotian (il is
panicularly significer in view oflhe fact that the new c!e*.nt appeds close lo n). This
angle lalies as agaiNi rhe lixed celesrial equalor lhe orientation ofthe ecliPtic slowly
laries lhroueh the year. lis fislE no 3 2,I on lhe nexl pag. shovs lhe wcsrcm pan of
$e cclcnial spheE wilh impodanl points &d angles m d de$nM below:
w' the west cardinal point,
t, rh€ v€ml cquinox, inl€eclion of.cliptic dd cqulor.
P, the Nonh c.l.sti.l pol€.
82