c-----------------------------------------------------------------------
c  04-09-04
c  Ruth A. Juarez
c  Independent Study Spring 2004
c  Dr. Bill Ryan
c  Program to convert data collected from Patterson_jan04 into a light 
c  curve
c  Input: results.dat 
c                                from image processing using IRAF
c Output: lightcurve.dat
c                               to generate lightcurve using gnuplot
c                               uses light.gplot to get gnuplot to plot this
c                                 and plrint.plt to print out a copy of the plot
c  LightCurves.f

      implicit none
c-----------------------------------------------------------------------
c  Parameters
c-----------------------------------------------------------------------
      integer maxobjs
      parameter (maxobjs = 20)
c-----------------------------------------------------------------------
c  Variables
c-----------------------------------------------------------------------
      character*11 chartime
      character*5 imagename
      real exptime, time, obstime,deltamag,avg
      real sigavg, sigdeltamag, sum
      real mag(maxobjs),merr(maxobjs)
      integer nobj, i, j, k, iobject,image,itemp
      integer iplot, idel, ncomps

c-----------------------------------------------------------------------
c  Data to be read into program
c-----------------------------------------------------------------------
      open (21, file='results.dat')
      open (22, file='lightcurve.dat')
c-----------------------------------------------------------------------
c  Getting input from the user re: how many objects they observed per 
c  screen in 'read' the '5' refers to reading the input from the 
c  keyboard (screen)
c-----------------------------------------------------------------------
      print *,"Enter the number of objects per screen"
      read(5,*) nobj

      print *,"Enter the object number to plot"
      read(5,*) iplot

      print *, "Enter the object number to delete or 0 not to delete"
      read(5,*) idel
c-----------------------------------------------------------------------     
c  Read in the data from the results.dat file
c  Print objects to the screen so that I know they are being read in 
c  correctly. Perform calculations on each image
c-----------------------------------------------------------------------

      do 200 image = 1, 200
        print *, "  "        
	do 190 iobject = 1, nobj
            read(21,*, end = 300) 
     &          imagename,chartime,exptime,mag(iobject),merr(iobject)
            print *,
     &      imagename, "   ",chartime,exptime,mag(iobject),merr(iobject)

 190    continue

c-----------------------------------------------------------------------
c  Call to subroutine to get change the time to a decimal string
c-----------------------------------------------------------------------
        call decimaltime(chartime,exptime,0.0,obstime)
  
c-----------------------------------------------------------------------
c  Do calculation for this image 
c-----------------------------------------------------------------------       
          sum = 0.0
	  sigavg = 0.0
	  avg = 0.0
	  ncomps = 0
	  do 40 itemp = 2, nobj
	    IF (itemp .ne. idel) THEN
	      ncomps = ncomps + 1;
	      sum = sum + mag(itemp)
	      sigavg = sigavg + merr(itemp)**2
	    END IF 
 40       continue
            avg = sum/real(ncomps)      
	    sigavg = sqrt(sigavg/real(ncomps))
	    deltamag = mag(iplot) - avg
            sigdeltamag = sqrt((merr(iplot)**2 + sigavg**2)/2.0)
	write(22,195), obstime,deltamag,sigdeltamag
        print *, obstime, deltamag, sigdeltamag 
 195    format (f12.4, 3x, f8.3, 3x, f8.3)        
 
 200  continue
 300  continue 

      stop 
      end

c%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
c this subroutine reads the time and converts it to time in decimal form
c this subroutine used with permission of author Carlos T. Martinez
c***********************************************************************
c
      subroutine decimaltime (ctime,timeint,corrtime,time)
c
c***********************************************************************
c
c calculate time in decimal form
c    
c      Input:
c       ctime   : the characters read in by readimg
c       timeint : integration time    (seconds)
c       corrtime: the corcection time (minutes)
c     Output:
c       time    : the decimal time the image was taken (hours)
c
c
      character*11 ctime
      real corrtime, timeint, time
c
c  read and calculate time from filelist info

c  hours
      kbegin = 1
      kend = index (ctime(kbegin:),':') - 1
      read (ctime(kbegin:kend),*) hour

c minutes
      kbegin = kend + 2
      kend = index (ctime(kbegin:),':') - 2 + kbegin
      read (ctime(kbegin:kend),*) min

c  seconds
      kbegin  = kend + 2
      read (ctime(kbegin:),*) sec

c
c  calculate decimal time
c
      time = real(hour) + real(min)/60.0 + real(sec)/3600.0 

c
c Add the correction for the integration time
      time = time + timeint /(2.0 * 3600.0)

c          
c option to correction of  time  
c       
               time = time + corrtime/60.0             
c
c

      return 
      end
c
c%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
c