带食的日行迹
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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…
日轨摄影术与日行迹
2022年7月2日 Solargraphic Analemmas Image Credit & Copyright: Dawid Rycabel (Pinholove) Explanation: For the northern hemisphere June 21 was the summer solstice, the Sun reaching its northernmost declination for the year. That would put it at the top of each of these three figure-8 curves, or analemmas, as it passed through the daytime sky over the village of Proboszczow, Poland. No sequence of digital exposures was used to construct the remarkable image though. Using a pinhole camera fixed to face south during the period June 26, 2021 to June 26, 2022, the image was formed directly on a single sheet of photographic paper, a technique known as solargraphy. The three analemmas are the result of briefly exposing the photo paper through the pinhole each day at…
台北上空的日行迹
2022年6月21日 Analemma over Taipei Image Credit & Copyright: Meiying Lee Explanation: Does the Sun return to the same spot on the sky every day? No. A better and more visual answer to that question is an analemma, a composite of images taken at the same time and from the same place over the course of a year. The featured analemma was compiled at 4:30 pm many afternoons from Taiwan during 2021, with the city skyline of Taipei in the foreground, including tall Taipei 101. The Sun’s location in December — at the December solstice — is shown on the far left, while its location at the June solstice is captured on the far right. Also shown are the positions of the Sun throughout the rest…
落日时分的日行迹
2019 June 21 落日时分的日行迹 影像来源及版权: Marcella Giulia Pace 说明：今天世界时间15点54分夏至来临之时，太阳在其每年穿过地球天空的旅程中会到达赤纬最北的位置。在天文学上，夏至标志着北半球夏季和南半球冬季的开始。今天也是北半球日出到日落之间白昼最长的一天。实际上，夏至的太阳位于这幅合成影像的顶部附近，也就是由太阳位置绘制的日行迹或8字曲线最北点。这道日行迹是由从2018年6月21日到2019年6月7日，每十天在同一时间拍摄的影像构建而成。拍摄时间被选择为一年中日落时间最早的冬至附近，因此日行迹的最低点正好与影像左侧一览无余的海平面相接。沿地平线向右（北）分布的落日以秋分的落日为中心，以夏至的落日结束点。 Sunset Analemma Image Credit & Copyright: Marcella Giulia Pace Explanation: Today, the solstice is at 15:54 Universal Time, the Sun reaching the northernmost declination in its yearly journey through planet Earth’s sky. A June solstice marks the astronomical beginning of summer in the northern hemisphere and winter in the south. It also brings the north’s longest day, the longest period between sunrise and sunset. In fact the June solstice sun is near the top, at the most northern point in the analemma or figure 8 curve traced by the position of the Sun in this composite photo. The analemma was created (video) from images taken every 10 days at the same time from June 21, 2018…