南半球下午的日行迹

南半球下午的日行迹

ByNASA中文

2023年9月23日 Afternoon Analemma Image Credit & Copyright: Ian Griffin (Otago Museum) Explanation: An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day for one year. To make this one, a 4×5 pinhole camera was set up looking north in southern New Zealand skies. The shutter was briefly opened each clear day in the afternoon at 4pm local time exposing the same photosensitized glass plate for the year spanning September 23, 2022 to September 19, 2023. On two days, the winter and summer solstices, the shutter was opened again 15 minutes after the main exposure and remained open until sunset to create the sun trails at the bottom and top of the curve. The…

11公里高空的南天

11公里高空的南天

ByNASA中文

2021年01月30日 Southern Sky from 38,000 Feet Image Credit & Copyright: Ralf Rohner Explanation: Celestial sights of the southern sky shine above a cloudy planet Earth in this gorgeous night sky view. The scene was captured from an airliner’s flight deck at 38,000 feet on a steady westbound ride to Lima, Peru. To produce the sharp airborne astrophotograph, the best of a series of short exposures were selected and digitally stacked. The broad band of the southern Milky Way begins at top left with the dark Coalsack Nebula and Southern Cross. Its expanse of diffuse starlight encompasses the the Carina Nebula and large Gum Nebula toward the right. Canopus, alpha star of Carina and second brightest star in Earth’s night is easy to spot below the…