function norh_cen,index,roll=roll,from_imgcen=from_imgcen

;+
; NAME:
;       norh_cen
;
; PURPOSE:
;       Return the Sun center corordinate in pixel unit
;       from the left-bottom corner of an NORH Field of View
;
; CALLING SEQUENCE:
;       cen=norh_cen(index)
;
; INPUTS:
;       index: index structure
;
; OPTIONAL OUTPUT:
;       from_imgcen: from image center
;       roll: Roll angle (default is zero array for NORH)
;
; HISTORY:
;       Writtern 1998-05-29 TY
;       Modified 1999-01-04 TY added from_imgcen
;       Modified 2000-04-19 TY based on V. Grechnev's suggestion
;
;-

mx=n_elements(index)

out = index.norh.solcen

if keyword_set(from_imgcen) then out = out-fix(norh_gt_shape(index))*0.5

roll=fltarr(mx)
if mx eq 1 then roll=0.

return,out
end