Visibility of Luna and Lunar Crescent

lo bc -50 N sords on aveas. f6r rlc Su, 0Ei itulud.s ihc affet of dE Ef4clion
and thc sni dian.ter bo$. For a mor€ accwtc valuc the &rul s.mi dimet r SD,
rhould be calculal.d fmo dE didea of1h. Su ed suh.actcd tioh d..veagc afi*l
of Glhction, fte chag. in l.hp€dl@ in ihe niddle laritDd.s my lary thjs by @ud
20 seconds of tinc ed tbe baromctric pres6res nay caue a veiaion of dother 12
*con& of time. Ho{€v.r 6 rhcse varia{otu cd nol LE d.temired a priori the avcEgc
afects m co.nd.ed in crlculalions. Unog fte $..drd slrjM. ?01h. hou anqlc oflh.
object is then eloluared as:
(21.t 4
Thus rh€ liBr dppro\,maion for lhe rhe ofrisng of$e obled h:
T, =UTO - E.
12.1tJ)
And $at ofrhe s. in8 isl
T, =Wtr+ Ho
(2.7.t4\
Thes. e only !h. n6t app,oxinarion3 for lh€ tines of swise ahd the sunsel
Esp.ctirely. Fomularing ihe lin a8unors for €.ch of fien Fpaan.l, rh. c@rdinar.s
of lbe Su ha\e b be catculared aglin. The
Grecrwich sid.El rinc orrcspondjns ro
borh t &d I h6 ro be obained as:
r-Ta+J6O.98564TTy'15
12.7.\5)
,1 or I e rlEr l@at lFu ogte
4d ihc &imurh of th. obj..t is
12.1.t6)