FUNCTION ymdh2jdf,year,month,day,hour

; This function is basically a wrapper for ymd2jd.pro from the
; JHU/APL IDL library.  It includes the specification of a (possibly
; fractional) hour of the day, and returns a (possibly fractional)
; Julian date.

ijd=ymd2jd(year,month,day)
RETURN,DOUBLE(ijd)+(hour-12.)/24.
END