Main Difference – Dawn vs Twilight
Dawn and twilight are two time periods which are closely related to the movement of the sun. The time of the two phenomena depends on the time of sunset and sunrise. Twilight is the period between light and darkness when the sun is below the horizon. Dawn is the period between the beginning of morning twilight and sun rise. The main difference between dawn and twilight is that dawn occurs in the morning whereas twilight occurs during both sunset and sunrise.
What is Dawn
Dawn is the time of day when light first appears. It is the beginning of twilight, before sunrise. At this time, the sun is still below the horizon, but there is weak sunlight.
The start of the dawn have different phases, and it is the degree of the sun and the amount of sunlight that differentiate these three phases. They can be classified into three types:
- Astronomical dawn is the time period where the Sun is 18 degrees below the horizon in the morning. At this time, the sky is not completely dark.
- Nautical dawn is the time period where the Sun is 12 degrees below the horizon in the morning. At this time, some objects can be distinguishable.
- Civil dawn is the time period where the Sun is 6 degrees below the horizon in the morning. There is enough light to see objects, and this is the time for the outdoor activities to begin.
What is Twilight
Twilight is the time period where the sun is below the horizon, yet there is light on the outside. This is produced by the diffusion of sunlight in the upper atmosphere, illuminating the lower atmosphere so that the surface of the Earth is neither completely lit nor completely dark. Twilight occur before the sunrise and after the sunset. Dawn is the beginning of the twilight before sunrise and dusk is the end of twilight after sunset. Like dawn, twilight too can be categorized into three phases: civil twilight, nautical twilight, and astronomical twilight. The image below explains the difference between these phases.
The duration of the twilight period also varies to a great extent depending on the latitude; it can last from a few minutes in equatorial regions to many hours in Polar Regions.
Difference Between Dawn and Twilight
Time Period
Dawn is the beginning of twilight, before sunrise.
Twilight is the time period between dawn and sunrise, and sunset and dusk.
Occurrence per Day
Dawn occurs once per day.
Twilight occurs twice per day.
Connection
Dawn is the beginning of twilight.
Twilight starts with the dawn.
Image Courtesy:
“Twilight subcategories” By TWCarlson – Own work, (CC BY-SA 3.0) via Commons Wikimedia
“Amanhecer nos Portais” By Carlos Perez Couto – Own work (CC BY-SA 3.0) via Commons Wikimedia
