Visibility of Luna and Lunar Crescent

@l@) of lhb wolk lb@ e 33 .M our of which 18 @ potiliv. sidines
with binoculd or 1el.$op6 dd th@ extra otdinary ces of unaid.d sidli.g
(ob$flalion no. 189,455 add 2?4) lh.t is dillcral fren fi. @ @sidercd bv
Yallop, Al lhe tine of Yallop {1998) lhis wG thc linil helow shich n ws
NW.d that il is nol Posible 10 c thc lhin .t snl n@n .v.n vilh a lel4oF
Alloeing I' for hoiienlal panllax of lhc Moon, and ienoring th' eff'cl of
rcfa.liol\ fo. & aptent .longadon of ?q5, ,'{XC, = 8c5 lf ,'lZ = 0p rhis
coresponds to . lowr linit of I = -{ 2l2 Wilhout good fidding lgles@p* md
posidoml infomation, obsne6 aa unlikelv [o w lhc crc$"t helow this limn
(E)
(r)
TheE is a lheoEical cul{fi Point *hen th. appatcnl elonSdlion of lhe Moo'
frem the sm is ?", knom 6 lhe Ddjon linir (Ddjon l9l2 1936, llvas' l98lb
nabohi el al, l99S) This limit is obtained bv extlapolatine obedalions nade al
lager elongtions. Allowing t" for hori@nul p@lld ofth' Moon a'd i8f,olrng
rhe effect ofrefEcion, ah.ppor€nr elongarion o' 70 is eqnivalent 1o
''{'R'1 = 8'
Wirh ,,llcl, = 8'ed D,42 = O! the corespondine low€r linil on I is -O 291'
However, in Yallopt lable 4 th€E tte 2l enfiies witl onlv ] posilive sightine
with a bin@uld fot I < 4 212 ed no sighting claim wilh s_aided cve ln lable
in apFndix-lll (se@nd lst colw) th* ae l8 c*s ir the mse -0 212 2 4
>
-0 299 oulofwhich there atc 7 sishdng snh binocuhr ot tlescopes and onlv 2
claims of un_aided siShdngs (obsdation los 389 and 455) Both the*
obfdrtio.s dcviak from all the crit.ria considered up b lns po'nl
The table in .ppendixlll G4ond last cotumn) or this wod( shoss 66 cases wtrr
-0 299 > q ed therc is one.xtra ordiMry claim of sishtins
opti*l aid (obs .o. 189) Ap&t fron $is lheE is no posilive siehting silb o!
wilhoul opdcal sid. In lable 4 of Yatlop tnee is no clain of €Esce sisblins $
A@oding |o the visibilitv dNifiorion shos
divid.d into 5 tgions bv four consi&t_q val@s As lne
abovc, rhc suf4 of E nb b
aclual visibihY of lhe crescent