There are three twilights for each end of the day. Most people only know about one.
Civil twilight is the one most people call “twilight.” It is the time, morning and evening when the sun is 6 degrees below the horizon. In decent weather, you can see the brightest stars, the horizon, and objects on the ground quite clearly. During this twilight, you can see well enough outdoors to not need artificial light.
During nautical twilight, the sun is 12 degrees below the horizon. General outlines of objects on the ground are discernable, but the horizon is indistinct, and you really need additional light to do anything with any detail, such as checking your camera settings.
The third twilight, astronomical twilight, is the period when the sun is 18 degrees below the horizon. You can barely see any evidence of light from the sun, and it does not lessen the brightness of the stars. Flashlights or auxiliary light are definitely useful during this time.
We often photograph during nautical twilight as we did last night.
When people join us on the Outer Banks, the Cape Hatteras Lighthouse is often on their wish list, and this group was no exception. We got down there early enough to …