Visibility of Luna and Lunar Crescent

sin rr'r _ rh&
sn(e+a) @s(e+a)
erhlr (3.1.t) rs = sili(sin r!.r..(e + 6r+,L -,rr
0.l_6)
I. sphoical iridglc ABS:
stnaD . stn 4r @eP
(1.1.7)
and in spherial lridgle HCS:
sinfls=-l]1gll
co(@ + a)
l].l.8l
:l
glj!
".(
(:
t::!
!
;
!.
)
:9:.q
+a)
-t
[.
(3.3.9)
laegles Hs dd ss @ snall cqua$ons (3.3.6) lnd (1.3.9) yhld alnost sme lesutB s
thos by (1.3.1) ad (1.1.4). If the valuc of 9 b lege. then Hs dd as ae nol shalland
th€ spherical trisonoderric rsults (3.3.5) and (3.3.9) should be ned for doF Muale
11'e sienificdce of (3.3-6) is thlt if th. cphcme€des of both rh€ Su and the
Moor m tnoM @uErdy (aj th.y c rcw) ud rhe &gl. 900 (p + A) = v of etipri.
{irh ihe honan €lculalcd fom (1.2.7) rh. !.lE of HS @ bG aal@ted for rbc tire of
sUM for dt day of lhe yw !trd psrti.uldly for rh. dlt or rt y .Rc UE bnh ot ncq
92