Four observations per day, standard approach day observation sequence source days observed note twice once 1 A B A C a A 1 3 fiducial 2 A B C D - B 1 3 fiducial 3 A B C D - C 0 3 primary 4 A B D B - D 0 3 secondary . A C D day observation sequence source days observed note twice once 1 A B A C a A 1 4 fiducial 2 A B D E - B 0 5 fiducial 3 A B C D - C 0 3 primary 4 A B E D - D 0 3 secondary 5 A B C E - E 0 3 secondary . A B A day observation sequence source days observed note twice once 1 A B A C a A 2 4 fiducial 2 A B D E - B 1 5 fiducial 3 A B C B b C 0 3 primary 4 A B D E - D 0 3 secondary 5 A B D E - E 0 3 secondary 6 A B A C a . B D A day observation sequence source days observed note twice once 1 A B A C a A 1 6 fiducial 2 A B D E - B 1 6 fiducial 3 A B D F - C 0 3 primary 4 A B C E - D 0 3 secondary 5 A B D F - E 0 3 secondary 6 A B E F - F 0 3 tertiary 7 A B C B b . A D E day observation sequence source days observed note twice once 1 A B A C a A 1 7 fiducial 2 A B D E - B 0 8 fiducial 3 A B F G - C 0 3 primary 4 A B C D - D 0 3 secondary 5 A B E F - E 0 3 secondary 6 A B G D - F 0 3 tertiary 7 A B E F - G 0 3 tertiary 8 A B C G - . A B A day observation sequence source days observed note twice once 1 A B A C a A 2 7 fiducial 2 A B D E - B 1 8 fiducial 3 A B F G - C 0 3 primary 4 A B D E - D 0 3 secondary 5 A B C B b E 0 3 secondary 6 A B F G - F 0 3 tertiary 7 A B D E - G 0 3 tertiary 8 A B F G - 9 A B A C a . B D A day observation sequence source days observed note twice once 1 A B A C a A 1 9 fiducial 2 A B D E - B 1 9 fiducial 3 A B F G - C 0 3 primary 4 A B D H - D 0 3 secondary 5 A B C E - E 0 3 secondary 6 A B F G - F 0 3 tertiary 7 A B D H - G 0 3 tertiary 8 A B E F - H 0 3 tertiary 9 A B G H - 10 A B C B b . A D E day observation sequence source days observed note twice once 1 A B A C a A 1 10 fiducial 2 A B D E - B 0 11 fiducial 3 A B F G - C 0 3 primary 4 A B H I - D 0 4 secondary 5 A B D E - E 0 3 secondary 6 A B C F - F 0 3 tertiary 7 A B G H - G 0 3 tertiary 8 A B D I - H 0 3 tertiary 9 A B E F - I 0 3 tertiary 10 A B G H - 11 A B C I - . A B A day observation sequence source days observed note twice once 1 A B A C a A 2 10 fiducial 2 A B D E - B 1 11 fiducial 3 A B F G - C 0 3 primary 4 A B H I - D 0 3 secondary 5 A B D E - E 0 3 secondary 6 A B F B b F 0 3 tertiary 7 A B C G - G 0 3 tertiary 8 A B H I - H 0 3 tertiary 9 A B D E - I 0 3 tertiary 10 A B F G - 11 A B H I - 12 A B A C a . B D A day observation sequence source days observed note twice once 1 A B A C a A 1 12 fiducial 2 A B D E - B 1 12 fiducial 3 A B F G - C 0 3 primary 4 A B H I - D 0 3 secondary 5 A B D J - E 0 3 secondary 6 A B E F - F 0 3 tertiary 7 A B C G - G 0 3 tertiary 8 A B H I - H 0 3 tertiary 9 A B D J - I 0 3 tertiary 10 A B E F - J 0 3 tertiary 11 A B G H - 12 A B I J - 13 A B C B b . A D E day observation sequence source days observed note twice once 1 A B A C a A 1 13 fiducial 2 A B D E - B 0 14 fiducial 3 A B F G - C 0 3 primary 4 A B H I - D 0 3 secondary 5 A B J K - E 0 3 secondary 6 A B D E - F 0 3 tertiary 7 A B C F - G 0 3 tertiary 8 A B G H - H 0 3 tertiary 9 A B I J - I 0 3 tertiary 10 A B K D - J 0 3 tertiary 11 A B E F - K 0 3 tertiary 12 A B G H - 13 A B I J - 14 A B C K - . A B A