Blue hour — a timeframe Soon just before dawn (or right after sunset), when the sky turns intensive blue, as a consequence of which saturated blue shades begin to prevail in normal light-weight. The end with the astronomical evening is The instant if the sun is less than eighteen degrees underneath the horizon. Winter Solstice — would be

Nadir (Antizenith) — is a point while in the celestial sphere located under the horizon, reverse the zenith. In relation towards the Sunlight, This is actually the cheapest place arrived at by the Sunlight in its orbit, relative for the observer. The Sun's transition region taken by Hinode's Photo voltaic Optical Telescope Earlier mentioned th