2025年9月13日
Star Trails over One-Mile Radio Telescope
Image Credit & Copyright: Joao Yordanov Serralheiro
Explanation: The steerable 60 foot diameter dish antenna of the One-Mile Telescope at Mullard Radio Astronomy Observatory, Cambridge, UK, is pointing skyward in this evocative night-skyscape. To capture the dramatic scene, consecutive 30 second exposures were recorded over a period of 90 minutes. Combined, the exposures reveal a background of gracefully arcing star trails that reflect planet Earth’s daily rotation on its axis. The North Celestial Pole, the extension of Earth’s axis of rotation into space, points near Polaris, the North Star. That’s the bright star that creates the short trail near the center of the concentric arcs. But the historic One-Mile Telescope array also relied on planet Earth’s rotation to operate. Exploring the universe at radio wavelengths, it was the first radio telescope to use Earth-rotation aperture synthesis. That technique uses the rotation of the Earth to change the relative orientation of the telescope array and celestial radio sources to create radio maps of the sky at a resolution better than that of the human eye.
Tomorrow’s picture: tilts and spins
一英里射电望远镜上空的星轨
影像提供与版权: Joao Yordanov Serralheiro
说明: 在这幅令人回味的夜空景像中，英国剑桥马拉德射电天文台一英里望远镜的可操纵60英尺直径碟形天线正指向天空。为了捕捉这一戏剧性的场景，摄影师在90分钟内连续拍摄了30秒的曝光影像。这些曝光影像合成后，优雅地显示出反映地球每日自转的弧形轨迹。北天极是地球自转轴在太空的延伸，指向北极星附近。这颗明亮的星星在同心圆弧的中心附近形成了短短的轨迹。然而，这座历史悠久的一英里望远镜阵列也依赖地球的自转来运作。在射电波长下探索宇宙，它是第一个使用地球自转孔径合成技术的射电望远镜。这项技术利用地球的自转来改变望远镜阵列与天体射电源的相对方向，以创建解析度优于人眼的天空射电图。
明日的图片: tilts and spins
