The time between day and night when there is light outside is called twilight. The second twilight phase is the Nautical twilight. The geometric center of the Sun's disk is between 6 and 12 degrees below the horizon during nautical twilight. The horizon is faintly visible during this twilight phase in clear weather conditions. Use the below EENT calculator which helps you to calculate the resultant value of End Evening Nautical Twilight (EENT).
Just enter the Date, Latitude (N + S -), Longitude (W + E -) and GMT in this End Evening Nautical Twilight calculator to get the EENT result.