function norh_gt_expdur,index

;+
; NAME:
;       norh_gt_expdur
;
; PURPOSE:
;       Return the exposure duration in units of sec.
;
; CALLING SEQUENCE:
;       expdur=norh_gt_expdur(index)
;
; INPUTS:
;       index: index structure
;
; HISTORY:
;       Writtern 1999-11-23 T. Yokoyama
;       Modified 2000-04-19 TY based on V. Grechnev's suggestion
;-

return,index.norh.expdur
end