rw king and rj cappallo    august 1978   subroutine mtide
interface between vetide and pep.  mtide sets up
various vectors, calls vetide to calculate the solid body
tide raised by the earth and sun on the moon and alters the
appropriate spot coordinates .

mtide1 = 0  first call of mtide for a given spot:
calculate tides and correct spot coordinates
= 1  calls of mtide on successive iterations for a
given spot:  correct spot coordinates but do
not recalculate tides

etide requires that the relative coordinates of the
earth, sun, and moon be available in /coord/ arrays
xem and xm, and that the unit vectors from site to
source be available in xsitp0 or ysitp0 of /coord/
or /radcrd/, respectively, for kobj= 1,2.