太阳至日和银河
(原标题: Solstice Sun and Milky Way)
2021-12-21
浏览次数: 4
欢迎来到12月至日，这是北半球冬季和南半球夏季的第一天。季节、至日和春分日期的天文标记是基于太阳每年沿着黄道穿越地球天空的位置。在这个至日，太阳在UTC时间15点59分达到其最大南纬-23.5度，而它在天球上的赤经坐标是18小时。这使得位于人马座的太阳靠近银河系中心的方向。事实上，如果你能在暗淡的恒星和星云背景下看到今天的太阳（这很难做到，尤其是在白天……），你的视野可能会像这张合成全景图一样。为了拍摄这张照片，我们在纳米比亚黑暗的夜空下拍摄了美丽星系的照片，然后将它们拼接在一起，形成了全景。在2015年12月21日拍摄的一张快照中，太阳被数码叠加成一颗明亮的恒星，位于今天的北方冬至位置，靠近银河系的中心。探索+拓展：APOD研究生研究职位开放
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Welcome to December's solstice, first day of winter in the north and summer for the southern hemisphere. Astronomical markers of the seasons, solstice and equinox dates are based on the Sun's place in its annual journey along the ecliptic, through planet Earth's sky. At this solstice, the Sun reaches its maximum southern declination of -23.5 degrees today at 15:59 UTC, while its right ascension coordinate on the celestial sphere is 18 hours. That puts the Sun in the constellation Sagittarius in a direction near the center of our Milky Way galaxy. In fact, if you could see today's Solstice Sun against faint background stars and nebulae (that's really hard to do, especially in the daytime ...) your view might look something like this composited panorama. To make it, images of our fair galaxy were taken under dark Namibian night skies, then stitched together in a panoramic view. From a snapshot made on 2015 December 21, the Sun was digitally overlayed as a brilliant star at today's northern winter solstice position, close to the center of the Milky Way. Discovery + Outreach: Graduate student research position open for APOD
© Stefan Seip