Context: CREATE TABLE table_name_86 (ngc_number VARCHAR, declination___j2000__ VARCHAR, constellation VARCHAR, object_type VARCHAR)
Question: Name the total number of NGC number for sagittarius and diffuse nebula with declination of °02′
Answer: SELECT COUNT(ngc_number) FROM table_name_86 WHERE constellation = "sagittarius" AND object_type = "diffuse nebula" AND declination___j2000__ = "°02′"