astronomical twilight

Astronomical twilight is from the end of nautical twilight until the Sun is 18[degrees] below the horizon.

Venus is first in the night's parade, setting at the end of astronomical twilight. Jupiter glows far upper left of Venus while Saturn shines in the south.

Astronomical twilight ranged from 27 to 35 min, and averaged 28:53 (min:s).These averages correspond to the twilight times labeled in Figures 4 and 5.

We then used sunrise-sunset data from the National Oceanic and Atmospheric Administration and astronomical twilight data from the U.S.

So much so that the skies never get truly dark at this time of year, and the sky remains in an astronomical twilight for what little of the night we have.

Before sunrise, as the sun reaches a point 18[degrees] below the horizon, astronomical twilight begins.

In fact astronomical twilight (when the Sun is less than 18[degrees] below the horizon) lasts all night from May 24 to July 22 for those observing from the latitude of London (51[degrees] 30').

In the north of the country, 82 percent of the suicides occurred during the daylight months (including astronomical twilight)."

EDT April 28th), just before the end of astronomical twilight for Florida.