南天的仙女座星系

2022年10月21日

Andromeda in Southern Skies
Image Credit & Copyright: Ian Griffin (Otago Museum)

Explanation: Looking north from southern New Zealand, the Andromeda Galaxy never gets more than about five degrees above the horizon. As spring comes to the southern hemisphere, in late September Andromeda is highest in the sky around midnight though. In a single 30 second exposure this telephoto image tracked the stars to capture the closest large spiral galaxy from Mount John Observatory as it climbed just over the rugged peaks of the south island’s Southern Alps. In the foreground, stars are reflected in the still waters of Lake Alexandrina. Also known as M31, the Andromeda Galaxy is one of the brightest objects in the Messier catalog, usually visible to the unaided eye as a small, faint, fuzzy patch. But this clear, dark sky and long exposure reveal the galaxy’s greater extent in planet Earth’s night, spanning nearly 6 full moons.

Tomorrow’s picture: light-weekend

南天的仙女座星系
影像提供与版权: Ian Griffin (Otago Museum)

说明: 从新西兰南部北眺，仙女座星系的仰角从未超出地平线5度左右。而随着春天降临南半球，仙女座星系在9月下旬的子夜时分升到最高仰角。这幅摄于约翰山天文台、以恒星为导引的30秒曝光长焦影像，就记录了这个最邻近我们的大螺旋星系，刚从南岛的高山崎岖群峰后方升起的景象。影像的前景则是倒映恒星的亚历山大湖之平静湖面。亦名为M31的仙女座星系，是梅西耶星表里最明亮的天体之一，然而在肉眼里，它通常只是一个昏暗模糊的小亮斑。然而，这幅摄于清朗幽暗天空下的长曝光影像，显示这个星系在地球夜空中的跨幅，其实将近有6个满月。

明日的图片: light-weekend