Sunrise and sunset are two of the most captivating moments of the day, when the sky is painted with exquisite shades of pinks and oranges. But what happens before and after these stunning displays? Recently, GBH meteorologist Dave Epstein shared his insights with Morning Edition co-hosts Jeremy Siegel and Paris Alston about the science behind these natural wonders.
According to Epstein, civil twilight is a period that occurs just before sunrise or after sunset when the sun is situated between zero to six degrees below the horizon. This time of day is particularly popular among people because it still provides light without the sun being visible. During this time, you can witness some truly breathtaking sunrises and sunsets that are approximately 30 minutes before or after their respective times.
Nautical twilight follows civil twilight and occurs when the sun is positioned between six to twelve degrees below the horizon. During this time, some of the brightest planets and stars become visible in our sky. As an added bonus, animals like deer become more active during nautical twilight, so you might catch sight of them as they forage for food or frolic in their natural habitat. Epstein humorously referred to this as “coyote time,” due to increased activity from crepuscular animals like deer that could sometimes lead to accidents with cars.
Finally, astronomical twilight takes place when the sun is located between twelve to eighteen degrees below the horizon. During this time, faint objects such as galaxies can be observed in our sky, but it’s not yet considered nighttime. In June months like June, astronomical twilight occurs very early and late due to its position in northern New England where true nighttime may not begin until late evening or even early morning hours during astronomical twilight.
