Astronomical twilight

Aug 23, 2017

This is the time of day when the sun has either set or is about to rise, but the sky is still being lit by its rays. At SALT we start our evening shift at sunset, preparing for the night ahead, but we only start taking science observations at the end of evening twilight. There is approximately 1.5 hours between sunset and the start of the night. Our night then usually ends shortly after morning twilight begins. The telescope is closed and parked and we head to bed.