An introduction to astronomy: designed as a text-book for the use of students in college. By Denison Olmsted ...

LUNAR RlElIcGUILA ITII FlS. 1385
Fig. fi60.
A
to~ - d f f
to:N"/tf, and tlhe inlclination is diminiser d as at N". In gencral,
while thle )moo1n is receding' from ooe of t1he nodes, its incllinuation is diminishing while it is approaclling a node, tlhe incelination is increasing.<'*
233.'lte )period occupliced by the sun in passing fi'om oto
of thie oon's nodes until it comes round to the same node
agalin, is called tihe synoieal i revolzttion qff t he nofde.'.Tlis
period is slhorter ttan the sdereal year, being only atbout 3.tG4,
days. For since the node sltifts its place to the wvestward 19~
35' p1er annum, tile stunll ill his annual revolutionl, comnes to it
so mln.uch before he completes his entire Circuit; and sinco tho
unt moves laboult a degree a day, tte synodical revoluttion of
th.e node is 365..19..... - 346, or more exactly, 34G6.619851. Tl
tilme fi'rom one new m0oo1n, or from one fuill moon, to anotlher,
is 29.530588 tday3s. i^o\ 1 synlodical revolutions of the iodes
contain very nearly 223 of thtcse peiiods.
For 346.619851x:19 J...585.8,
And 29.530588'( x 2.23-:...585.32.
HIeonce, if the sull and moon wereL' to leave the 1moo1's node
togcther, after the ll sun ]ad bl)ee round to the same node 1
timtes) the mlloonl would have performed very nearly 223 synodiceal revolutions, and would, thterfore, tat the end of tlhis:)eriod
meet at the same node, to repeat the same circuit. A-nd since
eclipses of the sun and mioon depend 1l)On the relative position
of thle sill, the 111oo11, and no(de, tlhcse p1)hmomnllt are rel)eated
in nearly the same older, in eacll of thlose periods. 111lonce,
o Francoutr, Uranog., p. 158; Robison's l'hys. Astronomy. Art, 261.