2024年的日行迹
See Explanation. Clicking on the picture will download the highest resolution version available.
请参阅说明。单击图片将下载可用的最高分辨率版本。
十二月的仲夏夜
2023年12月23日 A December Summer Night Image Credit & Copyright: Ian Griffin (Otago Museum) Explanation: Colours of a serene evening sky are captured in this 8 minute exposure, made near this December’s solstice from New Zealand, southern hemisphere, planet Earth. Looking south, star trails form the short concentric arcs around the rotating planet’s south celestial pole positioned just off the top of the frame. At top and left of center are trails of the Southern Cross stars and a dark smudge from the Milky Way’s Coalsack Nebula. Alpha and Beta Centauri make the brighter yellow and blue tinted trails, reflected below in the waters of Hoopers Inlet in the Pacific coast of the South Island’s Otago Peninsula. On that short December summer night, aurora australis also…
阳光下的183天
2023年12月22日 183 Days in the Sun Image Credit & Copyright: José Zarcos Palma Explanation: A single 183 day exposure with a pinhole camera and photographic paper resulted in this long-duration solargraph. Recorded from solstice to solstice, June 21 to December 21, in 2022, it follows the Sun’s daily arcing path through planet Earth’s skies from Mertola, Portugal. On June 21, the Sun’s highest point and longest arc represents the longest day and the astronomical beginning of summer in the northern hemisphere. The solstice date with the fewest hours of daylight is at the beginning of winter in the north, corresponding to the Sun’s shortest and lowest arc in the 2022 solargraph. For 2023, the northern winter solstice was on December 22 at 3:27 UTC. That’s…
南半球下午的日行迹
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…
三条日轨
2023年6月21日 Three Sun Paths Image Credit & Copyright: Marcella Giulia Pace & Giuseppe De Donà Explanation: Does the Sun follow the same path every day? No. The Sun’s path changes during the year, tracing a longer route during the summer than the winter. Pictured here, the Sun’s arc was captured from noon to sunset on three days, from highest in the sky to lowest: summer solstice, equinox, and winter solstice. The images were taken near Gatto Corvino Village in Sicily, Italy in 2020 and 2021. The path and time the Sun spends in the sky is more important in determining the season than how close the Earth is to the Sun. In fact, the Earth is closest to the Sun in January, during northern winter….
北纬63度的日晕
2022年12月21日 Sun Halo at Sixty-three Degrees North Image Credit & Copyright: Goran Strand Explanation: Happy Solstice! Today is the December solstice, marking an astronomical beginning of summer in the southern hemisphere and winter in the north. On its yearly trek through planet Earth’s skies, at this solstice the Sun reaches its southern most declination, 23.5 degrees south, at 21:48 UTC. About 4 days ago the Sun was near this seasonal southern limit and so only just above the horizon at local noon over Ostersund in central Sweden. This view looking over the far northern lakeside city finds the midday Sun with a beautiful solar ice halo. Naturally occurring atmospheric ice crystals can produce the tantalizing halo displays, refracting and reflecting the sunlight through their hexagonal…