Astronomy Picture of the Day——拱极星迹线
Circumpolar Star Trails
ImageCredit & Copyright: Gabriel Funes
Explanation: As Earth spins on its axis,the stars appear to rotate around an observatory in this well-composed imagefrom the Canary Island of Tenerife. Of course, the colorful concentric arcstraced out by the stars are really centered on the planet's North CelestialPole. Convenient for northern hemisphere astro-imagers and celestial navigatorsalike, bright star Polaris is near the pole and positioned in this scene to bebehind the telescope dome. Made with a camera fixed to a tripod, the series ofover 200 stacked digital exposures spanned about 4 hours. The observatory wasnot operating on that clear, dark night, but that's not surprising. The domehouses the Teide Observatory's large THEMIS Solar Telescope.
拱极星迹线
这幅精美的合成影像拍摄于加那利群岛特内里费岛，随着地球自转，这些恒星似乎围绕着一座天文台在旋转。当然，由恒星画出的彩色同心圆弧实际上是以地球的北天极为中心。对于北半球的天文爱好者和靠天体定位的航海者来说，在北极附近观测明亮北极星非常方便，它就位于这幅图像中望远镜圆顶的后方。这幅图像是由固定的照相机历时4个小时拍摄的一系列超过200张数字曝光照片叠加而成的。
参考文献：
https://apod.nasa.gov/apod/image/1901/Startrail_Funes.jpg
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Astronomy Picture of the Day——瑞典山脉远处的凸月