Visibility of Luna and Lunar Crescent

Chapter No. 3
ANCIENT, MEDIryAL & EARLY
2OTH CENTURY MODEU;
For calendarlcar purposes .s we as an Interes0n8 and chalte.ging
aslbnonlc.l p,obleh, jn rhe hbrory ofmanktnd there have ben constsrenr efiorts
ro delermano when and whererhe nek tunarcro@nt wll be lrst seen, t]e,esutrs
of these ealons have boen numeroG 6nd have been based on dtlle.ent technlques
6nd tools.lhose results can be temed as 't odets/Crireria tor the oadtest vtltbi|lry
or n€w runar cfescenr,. Most ot the earty modets are de ved dtioc y trom the
obs€oations of the new tunar crescent and are enDnjc.tin natlre. Some are based
on th€orellcalconslderations. MGI tmpon.nt of these eftons hctud6:
The Aabyroni.n rule of thumb .when the age ot the .ew Moon is 24
hooB only then the crescent can be seen,. fte redlscovery of the
more mrrhematrc.lly lnvolv6d crfte on ot Etong. on + LAG > 21.
lhal w6senunciatedw€ beforechisrian or. (Fatooht et at, 1999).
)
Tho cdena deveroped In ihe medtevat periods by Mus ms/Adbs
ba*d on obsenarion, sph6ri6t vtgonom€try and lhe ephemerid of
lhs Moon and the Sun (8rutn, 1977). This happen.d as earty .s rhe
llr)
The exploration or Foth€ ngham (1910), Maunda (1911) and orheF
ln the fi6l quarter ot the twontl6th @ntury. These effort! were moG
ot slallsti€l in natur€ based on th€ obseda ons mos y in Room by
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