Visibility of Luna and Lunar Crescent

visibihy cws inii.lly corceived by BNin, Thb clss includes Bruin's lidit, Yallop\
a-EIu€ cnt€rion md th. s-value cilerion th.l is d.velop€d in dis work
w. hdc ucd Schaf€ls algo.nhn ro cxploE rhe Epoaed ob$natoN out do
not cone uder ftc "Edily visible ' @ndition duc io YolloP md when $. cEse m
r€ponedly sen, AnohSsl th€s ob$palio$ ces lhal have ufavouiablc ha8litude
cont6l are critically exoined md some sft Gjccted (esp4iallv obs.nation nlnbcts
389 od 455) s $ey de lol consislent wnh.ny of lhe visibililv ctit rion consideEd in
rbis work. Bo$ lhce rcponed cses m nol .oDsi.lercd Fliable as .ven undq niehlv
exrgeerated .hosphdic t nFEtw md Glativ. humidny rhc magiudc contrdt is
foud ro b. unfavoubL for cE$ent visibilily ve foud al lcdl onc ob*oation wh€n
ile crc*enr sd Gpon€dly *n wi$olt.ny oflhal oid (obs. no. 274) ed thal is nol
co.sistent wilh any cilcrion bul havc 6 lalourable nagnifude co 6t fo! tlalivc
humidiry less than 50% and atnospheric lefrpcrature aound l0 deglee centiSBde
Apan fron obervarion nDmb.6 389 sd 455 1nee e ll olh.r caes shen the
cEse w4 r.poncdly s@ without oPlical .id but ihe ma8lilud. .ont6l ws not
favowbt.. Howvcr,olee m ofFsitiv. ob$nado$ re consined wilh ar lcsl on€
oder crilerion consitleed in 6is sork A3 the brighhess model tE still nol pedecl
rneEfore thcs. I I obsenalio.s ce nol bc dl.d out .s umliable.
The models $at @ dedued Iioh rh€ Bruin's isibilitv cud6 ud liniling
visibility cud6, th. Bruin's linil md YalloP s single p&meter (it .ion drc found to be
consisr.d qith.{h other. Bolh hav. stmosl.quivaldt succGs Frc€ntagc br Bruin s
We ha!. developed new visibihy curves and limiting visibililv curlcs using the
brid nss mod.h due 10 schaeler md o$es O. the basis ofthese n'* cuBes a new
dara *t ad a ncw sinsle pmetei cril.rion b d.duced The .s liniting visibililv
cufl* havc lcad lo a slishdy nodifi.d "h.st lime of cE$nt visibilnv Our nw
visibiliry cril..ion, thc r-value ;ilaion, is found lo be norc succ6sful fot posnive
168