恒星、云气与尘埃后方的星系

2022年10月19日

A Galaxy Beyond Stars, Gas, Dust
Image Credit & Copyright: Howard Trottier; Text: Emily Rice

Explanation: Do we dare believe our eyes? When we look at images of space, we often wonder whether they are “real”, and just as often the best answer varies. In this case, the scene appears much as our eyes would see it, because it was obtained using RGB (Red, Green, Blue) filters like the cone cells in our eyes, except collecting light for 19 hours, not a fraction of a second. The featured image was captured over six nights, using a 24-inch diameter telescope in the Sierra Nevada Mountains, in California, USA. The bright spiral galaxy at the center (NGC 7497) looks like it is being grasped by an eerie tendril of a space ghost, and therein lies the trick. The galaxy is actually 59 million light years away, while the nebulosity is MBM 54, less than one thousand light years away, making it one of the nearest cool clouds of gas and dust — galactic cirrus — within our own Milky Way Galaxy. Both are in the constellation of Pegasus, which can be seen high overhead from northern latitudes in the autumn.

Tomorrow’s picture: open space

恒星、云气与尘埃后方的星系
影像提供与版权: Howard Trottier; 文稿: Emily Rice

说明: 我们能信任自己的眼睛吗？当我们观看太空影像时，我们经常想知道它们是否“真实”，然而，真实的答案也经常依情况而异。在此例证里，影像所呈现的和我们肉眼所能见的一致，因为使用 的RGB（红、绿、蓝）滤镜，其感光特性和我们眼睛的锥细胞一样，只不过，集光时间不再是几分之一秒，而是长达19小时。这幅摄于6个晚上的主题影像，是使用座落在美国加州内华达山脉的61公分口径望远镜所拍摄。影像中心处的明亮螺旋星系（NGC 7497），看似被太空幽灵的怪异卷须所捕获，而这正是解谜的关键。这个星系离我们5900万光年远，而星云则是离我们不到1千光年的MBM 54，因此，它是近在我们银河系之内的银河卷云，也是最邻近我们的气体和尘埃冷云之一。影像中的这二个天体，都位在秋季高悬在北半球高纬度地区头顶的飞马座之内。

明日的图片: open space