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 11:00, 12:00, and 13:00 CET. Groups of dashed lines on the sides show partial tracks of the Sun from daily exposures made every 15 minutes. Over the year-long solargraphic photo opportunity clouds blocking the Sun during the pinhole exposures created the dark gaps.

Tomorrow’s picture: doomed moon of Mars

日轨摄影术与日行迹
影像提供与版权: Dawid Rycabel (Pinholove)

说明: 6月21日是北半球的夏至，在一年之中，太阳抵达赤纬最北的位置。因此，当它通过波兰Proboszczow村上方的白昼天空时，夏至的太阳位在这3个8字形日行迹的顶端。然而，建构这幅精采影像并没有使用数位序列曝光成像。在横跨2021年6月26日至2022年6月26日的拍摄期间，所使用的设备是一部固定朝南的针孔相机，直接在一张相纸上成像，这种技术称为日轨摄影术（solargraphy）。影像中的这3个日行迹，在是每天分别在欧洲中部时间11:00、12:00和13:00透过针孔短暂进行相纸暴光的成果。日行迹二侧的虚线光迹组，呈现每天每15分钟进行一次曝光所记录的部分日轨。在长达一年的日轨摄影中，于针孔曝光成像期间乱入的云朵，遮住了太阳并造成影像里黝黑的间隙。

明日的图片: doomed moon of Mars