At what time does evening officially become night?

Question

At what time does evening officially become night?

Answer 1

When the planets rise and the stars begin to shine, then it's the beginning of night.  Evening and night are overlapping notions.  Late in the evening can somethimes be indistinguishable from early at night.  

True night, though, is when the Milky Way dominates the sky.

Answer 2

right now its like at 12am to be consider

Answer 3

According to my Pokémon Pearl game, about 7 PM.  But, it's not always the best indicator of reality.

Answer 4

In mathematics (e.g., celestial mechanics) it is when the centre of the Sun's disk's true position is exactly 90 degrees from the observer's zenith (theoretical horizon).  If your are at sea, the Sun will still appear a full degree above the horizon.  The difference is due to the refraction caused by Earth's atmosphere.

In astronomy, sunset is when the top of the image of the Sun's disk is 90 degrees from the zenith.  This could be as much as 5 to 10 minutes after the first one (takes into account the apparent radius of the Sun's disk, and the refraction due to Earth's atmosphere)

If you are at sea (where the apparent horizon is very close to the theoretical horizon), that is when the last bit of Sun disappears over the horizon.

This is the beginning of the Civil twilight.  During civil twilight, there is enough light to go about your business as if it were still day.

When the Sun is 6 degrees below the theoretical horizon, it is the end of the Civil twilight and the beginning of the Nautical twilight.  

It is dark enough to see a few stars (the brightest ones), yet light enough to see the horizon.  Navigators can measure the angle (with a sextant) from the horizon to the navigation stars.

When the Sun is 12 degrees below the theoretical horizon, it is the end of the Nautical twilight and the beginning of the Astronomical twilight.  

Too dark to see anything on the ground, but there is just enough light in the upper atmosphere to interfere with deep sky observations and astrophotography.

When the Sun is 18 degrees below the horizon, it is the end of Astronomical twilight.  It is now night for astronomers.

The symmetrical sequence (in reverse) precedes sunrise.

Answer 5

Cold hearted orb that rules the night,

Removes the colours from our sight,

Red is gray and yellow white,

But we decide which is right.

And which is an illusion?

Answer 6

When the sun has completely set. I think

Answer 7

Raymond's answer is correct and gives you all the steps that precede the event of night... I can not add to his asnwer, and

it would be wasteful of both of our time for me to repeat it in this paragraph space.

Answer 8

that's just a matter of perception... you could call it when sun sets, or when darkness actually befalls the land.... there is a considerable diffrence..