! crude registration and mosaic construction
rd 1 red/1r
rd 2 red/2r
rd 3 red/3r
rd 4 red/4r
rd 5 red/5r

create 101 n=3*512 sr=1 sc=1
do i=1,5
  copy $i+10 $i
  bin $i+10 bin=4
end_do

! Make rough mosaic for star identification
add 101 11 dr=512 dc=512
add 101 12 dc=512
add 101 13 dc=512 dr=2*512
add 101 14 dc=2*512 dr=512
add 101 15 dr=512

do i=2,5
  tv 101
  printf 'Mark stars common between 1 and %i' i
  printf 'image 1: '
  tv 1
  mark 1 new ref
  printf 'Image %i: ' i
  tv $i
  mark color=2 exit
  mark $i new ref

  register 1 $i load header trans
  dc={i:x(01,1)}
  dr={i:x(01,2)}
  printf '%i %2f10.3' i dc dr >>./car.shift
end_do

! Now create the final mosaic using the derived shifts
open input ./car.shift
create 101 n=3*512 sr=-512 sc=-512
create 102 n=3*512 sr=-512 sc=-512
skytot=0
do i=1,5
  copy $i+10 $i
  if i>1
    read input
    dc=@input.2 dr=@input.3
  else
    dr=0 dc=0
  end_if
  bin $i+10 bin=4
  sky $i+10
  sub $i+10 c=sky
  skytot=skytot+sky
  fixhead $i+10 origin
  shift $i+10 dr=dr/4-0.75 dc=dc/4-0.75 bilinear
  add 101 $i+10
  div $i+10 $i+10
  add 102 $i+10
end_do
 
div 101 102
div 102 102
mul 102 c=skytot/5
add 101 102
 
end