;+
; NAME:
;       BSC_LRANGE
; PURPOSE:
;       extract wavelength ranges from BSC spectra for fitting
; CALLING SEQUENCE:
;       lrange=bsc_lrange(ww,ff)
; INPUTS:
;       ww = wavelength array
;       ff = flux array
; OUTPUTS:
;       lrange = [w1,w2,w3,w4...w2n-1,w2n] 
;              = n pairs of selected wavelength ranges
; KEYWORDS:
;       over   = use existing plot
; HISTORY:
;    15-Feb-94, D. Zarro (ARC), Written
;    21-Jun-94, DMZ , improved point selection via PCURSE
;-

  function bsc_lrange,ww,ff,over=over

  if not keyword_set(over) then begin
   bcs_spec_plot,ww,ff,psym=10
  endif

  mess=['USE CURSOR TO MARK FIT REGIONS','PRESS RIGHT BUTTON WHEN DONE']

  pcurse,lrange,xl=.6,yl=.9,new=mess
  np=n_elements(lrange)
  if np le 1 then begin
   message,'insufficient points selected - using whole range',/cont
   if not keyword_set(over) then lrange=[min(ww),max(ww)] else lrange=!x.crange
  endif 

  np=n_elements(lrange)
  if (np mod 2) ne 0 then lrange=lrange(0:np-2)

  message,'# of ranges selected = '+string(np/2),/cont

  return,lrange & end