Twilight

You beaudy.  I learned something.
I regularly do a cleansing thing where I go without food for the day.  I make a day like they do in the middle east from sundown to sunup.  Sundown is the start of a new day. 
So if you want to know when sunset is, I am your man.  Right now it is 5.12.  Not long ago it reached its earliest point which was 5.01.  Now the days are getting longer again.
Anyway, I was wanting to determine when sunset was.   (I actually like that as it means I have a meal in the evening.)  While I was looking into it, I saw stuff talking about twilight.  I really thought twilight is twilight.  But no.  There are three stages of twilight.  I had no idea.
The stages of twilight are determined by the distance of the sun below the horizon. (I take their word on this one)  Civil, Nautical and Atmospherical. 
​Civil is when the sun has gone below the horizon, but artificial light is not needed. (the sun is up to 6 degrees below the horizon).  At sunset it is the first part of twilight (it is opposite in the morning.)  The next stage is the Nautical twilight.  (the sun is between 6 and 12 degrees below the horizon) The horizon is faintly visible as are some of the brighter stars.  Sailors could use the position of the stars in relation to the horizon to navigate successfully.  That is why it is called nautical twilight.
I confess this one I find harder to distinguish.  I wandered into the yard and said to myself “this is civil twilight.”  Not so for nautical twilight.  All I know is outlines of things can be seen but I need artificial light to clearly distinguish things closer up.
I think I can tell when Astronomical twilight is on. (the sun is between 12 and 18 degrees below the horizon) It is defined as a period of twilight when astronomical observations of sources of sky light are visible and can be studied.  If there are other light sources they can interfere with observations.  This is why in the city the sky seems less habited.  (there is too much light)
Anyway all this because I wanted to know when sunset was.  I found out what I wanted and a lot more besides.