Dawn of a New Day
Comments
Basically, astronomical dawn is about 1 hour 4 minutes before the sun comes up on the horizon. (More if you’re not on the equator).
Astronomical twilight is the period from 1 hr 4 minutes before dawn, to 52 minutes before dawn (again, these are for somebody near the equator). And the same for times after sunset.
So, is it darker 1 hr 4 minutes before dawn, or 52 minutes before dawn?
References :
March 18th, 2010 at 6:08 pm
What is the difference between Astronomical dawn and Astronomical twlight ?
1.What is the difference between Astronomical dawn and Astronomical twlight ?
2. Which is more darker of the two?
Additional Information
Astronomical dawn is the time at which the sun is 18 degrees below the horizon in the morning. Astronomical dawn is that point in time at which the sun starts lightening the sky. Prior to this time, the sky is completely dark.
Astronomical twilight is defined as the time when the center of the Sun is more than 12° below the horizon but less than 18°. Most casual observers would consider the entire sky already fully dark at the limit of astronomical twilight, and astronomers can easily make observations of point sources such as stars, but faint diffuse objects such as nebulae and galaxies can only be properly observed beyond the limit of astronomical twilight.