C+
C NAME:
C	sidereal.f
C PURPOSE:
C	Calculate sidereal time from the time of the vernal equniox. 
C CATEGORY:
C	Abnalu=ysis
C CALLING SEQUENCE:
C	call sidereal(JDX,iyrveq,doyveq8,alonx,st)
C
C INPUTS:
C	JDX         real*8            Julian date of the observation
C	iyrveq	integer	      Year of the vernal equinox of the observation
C	doyveq8	real*8	      day of year of the observation at the vernal eguinox in UT time
C     alonx       real              longitude of the observation (ASHI)
C
C OUTPUTS:
C	st		real		      sidereal time at ASHI in degrees since the beginning of the day
C
C FUNCTIONS/SUBROUTINES:
C     julian8
C
C MODIFICATION HISTORY:
C	April-2022, Bernard Jackson (UCSD)
C-
	subroutine sidereal(JDX,doyveq8,alonx,st)
	  integer   iyrveq            ! Year of the vernal equinox of the observation
        real      alonx             ! longitude of the observation (ASHI)
        REAL*8    JDX               ! Input time of the ASHI observation in Day of Year in UTC
	  real*8    doyveq8,	      ! day of year of the observation at the vernal equinox in UTC
     &            caveqdoy,         ! calendar days since the vernal equinox
     &            daytidif,         ! difference in sidereal days from calendar days
     &            sidays            ! sidereal days since the vernal equinox

          print*, ' Into sidereal',JDX,doyveq8,alongx

          daytidif = 1.0d0 - 0.00273032407d0
          caveqdoy = (JDX-doyveq8)+(alonx/360.0d0)   ! calendar days since the vernal equinox plus offset for longitude
          print*, ' caveqdoy =',caveqdoy
          sidays   = caveqdoy/daytidif
          isidays  = sidays
          st       = (sidays-isidays)*360.0          ! time since the beginning of the sidereal day in degrees
C          write(*,'(3F14.8,I5,F14.8)') daytidif, caveqdoy, sidays, isidays, st

	  return
	end