星像迹线与春分日出
影像来源与版权:Juan Carlos Casado (TWAN, Earth and Stars), Andrea Rodriguez Anton

说明:这幅拍摄于3月19日的昼夜合成全景影像呈现了星像迹线与日出。这一景象是从西班牙拉纳瓦德圣地亚哥朝着东方地平线眺望所看到的。为了制作该影像,大约用了两个小时持续记录了这一系列数字照片,组合起来后追踪到了恒星在夜空中的同心圆运动。作为地球自转的一种映射,星像迹线向左上方的北天极和右下方的南天极弯曲。当然,那一天太阳位于天赤道附近,也就是在广角投影的一条对角线上。利用一台密集的调光滤波器每隔两分钟捕捉一次太阳的影像,并将它叠加在星像迹线上,而太阳则在黎明天空的正东方升起。然而,在这幅影像中,前景地景和当地的一座史前纪念碑被月光照亮。纪念碑的走廊几近面向正东和春分日出。
翻译:北京天文馆

Star Trails and the Equinox Sunrise
Image Credit & Copyright: Juan Carlos Casado (TWAN, Earth and Stars) Acknowledgement: Andrea Rodriguez Anton

Explanation: Stars trail and the Sun rises in this night and day composite panorama made on March 19. The view looks toward the eastern horizon from La Nava de Santiago, Spain. To create it, a continuous series of digital frames was recorded for about two hours and combined to trace the concentric motion of the stars through the night sky. A reflection of the Earth’s rotation, star trails curve around the north celestial pole toward upper left and the south celestial pole toward the lower right. Of course on that day the Sun was near the celestial equator, a diagonal straight line in the wide-angle projection. A dense dimming filter was used to capture the Sun’s image every two minutes. Superimposed on the star trails it rose due east in the morning sky. In the scene, foreground landscape and a local prehistoric monument were illuminated by full moonlight, though. The monument’s corridor faces nearly to the east and the equinox sunrise.
Astronomy Picture of the Day 03/21/2019