Visibility of Luna and Lunar Crescent

AD 617 during $c caliph.t of Umd bin Khafiab. Whltcvcr h. thc 1in. of adoplion, lhe
lslMh cal.ndrr. or dc Hiji c.l.nd& s@ wi$ Fnday l6ri ruly 622 AD on Julitu
calends which Moding b didft{c luMr or krdrhicslddd is l" diy ofMuha]m
(1" nonth ofe klmic y.ar) ofth. tsleic I (R.in8old & ftrshowii2, 2001). The
o,ficial dar. or adoprion oflhi!.h &d cal.rdd '@ b l'' Muhtu Il AH (and HijB)
Simpl. 34heh.s or 4rolh odd appoxidlions b$cd on long Lm 3vs.gs h.d
b€.n dcvi*d to pcparc long r.d cel.nd& in vid ol incrconv.uion ol lslmic drGs
&d tne d!t6 in oth.r lei-$lo ad el& olcndr d.r.s.
blanic legd syst h cgllcd Shdia , is lh. sou@ of lsldic tn+kcping ststn.
whil. le8.l pc.pls .rc efeglnd.d by seking sisbne fom $. *i.nlilic kno*l.dge.
Till th. rin. of sking of B.ddad by Hrl.su Xhu in AD 1258, Isluic law had
cvolv.d .ldr guidclires ao. elcndriol oNidcFlio.s (llya 1994). The olcndric.l
sddelircs ftlv.d undcr thc Islmic lN qn bc outlin d a follows:
i)
it
iit
l-.nsth of a lunar month is cnhe. 29 days or l0 days.
L.nA$ ol a lumr tlar is .ith.r 154 dlts or 155 dayr.
Tn rc can be . mdimuh of 4 cor*cutiE monrh. of l0 datr @h or 3
conscutive nomhs of29 &ys each.
E4h new nonth b.sins with fiBt sightns ot ncw lu@ cGccir ovd the
k$em hori@n .n.r ft. l@l ss.i,
v) Ailcmptr rhould bc nad. on 29u of ea.h honrh for sighring of ncw crcscnr.
lf il is nol scn on the 294 duc lo any l€en (stmnohic.l condirions or
w.thd connEints) thc noi$ should bc complckd a of l0 days.
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