/** Time Magazine claimed that
    "the next full moon on Friday the 13th isn’t expected to happen again for
    another 30 years—on Aug. 13, 2049"

    I've found almost every claim of this sort to be wrong, especially when
    time zones are involved.  Let's see if it's right.  (Hint:  it's right
    for the continental U.S. but wrong for the "US/Hawaii" timezone.)
*/
use sun.frink
tz = "US/Mountain"
tzf = ### dd u ###
//           ^ u is day number in week
d = #2019-09-13#
do
{
   f = fullMoon[d]
   fs = (f -> [tzf, tz])
   if fs =~ %r/13 5/
      println[f -> tz]
   d = f + lunarmonth
} while d < #2099-09-13#