To identify unique targets on the sky I use the "onksy" codes.

NOTE:   Use ./S/RUN1 to process 20191018 to get to this point. 
% cd /home/sco/ACM_work_Sep2019/red_20191018
% ./S/RUN1 

# Run iset finder and automatically build EX1 table 
% table_onsky_sets.sh ACMDAT A N   

Creates important files: 
  EX1.parlab,images,table 
  table_onsky_sets.out
  table_onsky_sets.RADEC

% cat table_onsky_sets.out
Summary of targets sets from table_onsky_sets.sh run
Number of images in input list      =     587
Number of unique targets identified =       8
Number of images with target values =      76
      1      28
      2      16
      3       1
      4      14
      5       1
      6       1
      7       1
      8      14

# Review the 28 images for iset=1  
% onsky_set EX1 1 Y N  
Create important files: 
   List.AllTargets, List.AllTargets.Text     (all targets) 
   List.FINAL_ISET  == the 3 image I manually selected in the onsky_set run.