Search the FAA for normal hours of operation under Part 107, you can find this: "You can fly during daylight or in twilight (30 minutes before official sunrise to 30 minutes after official sunset, local time) "
I applied for and have received approval via Airspace Authorization permit to fly up to 100' AGL in class C airspace for one day (thank you FAA!). The second page includes the Special Provisions of the permit, and in part says
a. This Certificate of Waiver or Authorization and the Special Provisions shall be in effect between civil sunrise and civil sunset local time. [ underlines added by me. ]
Of course, if you search anywhere within the FAA, (or anywhere for that matter) you will not find any definitions for civil sunrise or civil sunset , but only references to official sunrise or sunset. There are many places that refer to civil twilight, as previously defined above. I believe that the folks who created the Certificate probably meant to say civil twilight, not civil sunset/sunrise.
If you're confused already, here is what the National Weather Service has to say about things:
Civil Twilight:
I applied for and have received approval via Airspace Authorization permit to fly up to 100' AGL in class C airspace for one day (thank you FAA!). The second page includes the Special Provisions of the permit, and in part says
a. This Certificate of Waiver or Authorization and the Special Provisions shall be in effect between civil sunrise and civil sunset local time. [ underlines added by me. ]
Of course, if you search anywhere within the FAA, (or anywhere for that matter) you will not find any definitions for civil sunrise or civil sunset , but only references to official sunrise or sunset. There are many places that refer to civil twilight, as previously defined above. I believe that the folks who created the Certificate probably meant to say civil twilight, not civil sunset/sunrise.
If you're confused already, here is what the National Weather Service has to say about things:
Civil Twilight:
- Begins in the morning, or ends in the evening, when the geometric center of the sun is 6 degrees below the horizon. Therefore morning civil twilight begins when the geometric center of the sun is 6 degrees below the horizon, and ends at sunrise. Evening civil twilight begins at sunset, and ends when the geometric center of the sun is 6 degrees below the horizon. Under these conditions absent fog or other restrictions, the brightest stars and planets can be seen, the horizon and terrestrial objects can be discerned, and in many cases, artificial lighting is not needed.
- Begins in the morning, or ends in the evening, when the geometric center of the sun is 12 degrees below the horizon. In general, the term nautical twilight refers to sailors being able to take reliable readings via well known stars because the horizon is still visible, even under moonless conditions. Absent fog or other restrictions, outlines of terrestrial objects may still be discernible, but detailed outdoor activities are likely curtailed without artificial illumination.
- Begins in the morning, or ends in the evening, when the geometric center of the sun is 18 degrees below the horizon. In astronomical twilight, sky illumination is so faint that most casual observers would regard the sky as fully dark, especially under urban or suburban light pollution. Under astronomical twilight, the horizon is not discernible and moderately faint stars or planets can be observed with the naked eye under a non light polluted sky. But to test the limits of naked eye observations, the sun needs to be more than 18 degrees below the horizon. Point light sources such as stars and planets can be readily studied by astronomers under astronomical twilight. But diffuse light sources such as galaxies, nebula, and globular clusters need to be observed under a totally dark sky, again when the sun is more than 18 degrees below the horizon.
