2025年8月2日
Fireflies, Meteors, and Milky Way
Image Credit & Copyright: Daniel Korona
Explanation: Taken on July 29 and July 30, a registered and stacked series of exposures creates this dreamlike view of a northern summer night. Multiple firefly flashes streak across the foreground as the luminous Milky Way arcs above the horizon in the Sierra de Órganos national park of central Mexico, The collection of bright streaks aligned across the sky toward the upper left in the timelapse image are Delta Aquariid meteors. Currently active, the annual Delta Aquarid meteor shower shares August nights though, overlapping with the better-known Perseid meteor shower. This year that makes post-midnight, mostly moonless skies in early August very popular with late night skygazers. How can you tell a Delta Aquariid from a Perseid meteor? The streaks of Perseid meteors can be traced back to an apparent radiant in the constellation Perseus. Delta Aquariids appear to emerge from the more southerly constellation Aquarius, beyond the top left of this frame. Of course, the bioluminescent flashes of fireflies are common too on these northern summer nights. But how can you tell a firefly from a meteor? Just try to catch one.
Tomorrow’s picture: or …
萤火虫、流星与银河系
影像提供与版权: Daniel Korona
说明: 这幅梦幻般的北方夏夜，是由一系列在7月29日与30日拍摄的曝光影像，经过配准与堆叠后所呈现的。前景中多道萤火虫的闪光划过，而光辉的银河拱桥则横跨在墨西哥中部奥尔加诺斯山脉国家公园（Sierra de Órganos）的地平线之上。在这张缩时影像中，画面左上方排列整齐的亮线为「宝瓶座δ流星雨」（Delta Aquariid）所划出的轨迹。这场年度流星雨目前正处于活跃期，它与更广为人知的「英仙座流星雨」（Perseid meteor shower）时间重叠，共同点亮了八月的夜空。今年，八月上旬的午夜过后将是观星的黄金时段——月光微弱甚至无月，极适合观测流星。如何区分宝瓶座δ流星与英仙座流星？英仙座流星的轨迹可回溯至英仙座内的一个「辐射点」；而宝瓶座δ流星则看似从更南方的宝瓶座（画面左上方以外）射出。当然，在这样的北半球夏夜里，萤火虫生物发光的闪烁也相当常见。那要如何分辨萤火虫与流星呢？——试着抓住一只看看就知道了。
明日的图片: or …
