2022年03月29日:金星和火星：在夜空擦身而过-（Venus and Mars: Passing in the Night） [2022年03月29日:金星和火星：在夜空擦身而过-（Venus and Mars: Passing in the Night）--原图下载](https://apod.nasa.gov/apod/image/2203/VenusMars_Fairbairn_1433.jpg"onMouseOver="if (document.images)document.imagename1.src='image/2203/VenusMars_Fairbairn_960_annotated.jpg';"onMouseOut="if (document.images)document.imagename1.src='image/2203/VenusMars_Fairbairn_960.jpg';){mtitle title="金星和火星：在夜空擦身而过"/}Image Credit & Copyright: Carlos Kiko Fairbairn说明: 当两颗行星在夜空擦身而过时，通常在一周或更长时间里，它们彼此都很接近。例如在上面这例行星近合里，金星和火星在本月稍早的这段期间，二者相隔不到4度。数天前在巴西的Teresópolis小镇，拍下这幅由4张照片组合而成的主题影像时，当时金星在黎明前的天空中缓慢升起，而夜过一夜，火星则缓缓西沉。除了金星和火星之外，目前清晨的天空还可见到更遥远的土星。当然，它们只是在视角上发生近合，金星、火星和土星仍持续在我们太阳系的不同区域绕太阳运行。在下星期，土星和火星之间的视间距将降至四分之一度以下。{lamp/}原文：{mtitle title="Venus and Mars: Passing in the Night"/}Image Credit & Copyright: Carlos Kiko FairbairnExplanation: When two planets pass on the night sky, they can usually be seen near each other for a week or more.In the case of this planetary conjunction, Venus and Mars passed within 4 degrees of each other earlier this month.The featured image was taken a few days prior, when Venus was slowing rising in the pre-dawn sky, night by night, while Mars was slowly setting.The image, a four-part mosaic, was captured in Brazil from the small town Teresópolis.Besides Venus and Mars, the morning sky now also includes the more distant planet Saturn. Of course, these conjunctions are only angular -- Venus, Mars, and Saturn continue to orbit the Sun in very different parts of our Solar System. Next week, the angle between Saturn and Mars will drop to below a quarter of a degree.

2020年10月04日:氧、氢和硫等原子发光波段的猎户大星云-（Orion Nebula in Oxygen, Hydrogen, and Sulfur） 2020年10月04日:氧、氢和硫等原子发光波段的猎户大星云-（Orion Nebula in Oxygen, Hydrogen, and Sulfur）--原图下载{mtitle title="氧、氢和硫等原子发光波段的猎户大星云"/}Image Credit & Copyright: César Blanco González说明: 鲜少有天文景观，能像着名的猎户座星云这个邻近的恒星育婴室，这么善于激发着人们的想像。这个星云的辉光云气，环拱着座落在一个庞大星际分子云里的炽热年轻恒星。而在这幅主题影像里的许多丝状云气结构，其上是激波前沿，在该处，高速移动的物质撞击慢速移动的气体。跨幅约40光年、距离约1,500光年的猎户座大星云，和太阳都位在银河系的同一旋臂上。座落在着名猎户座腰带三星左下方、轻易可辨的猎户座大星云，是个肉眼可见天体。上面这幅主题照片，呈现猎户星云在氢、氧与硫原子气体个发光波段 的面貌。包括 马头星云在内的整个猎户星云複合体，在接下来的100,000年之内，会慢慢的消散匿迹。{lamp/}原文：{mtitle title="Orion Nebula in Oxygen, Hydrogen, and Sulfur"/}Image Credit & Copyright: César Blanco GonzálezExplanation: Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud. Many of the filamentary structures visible in the featured image are actually shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula spans about 40 light years and is located about 1500 light years away in the same spiral arm of our Galaxy as the Sun. The Great Nebula in Orion can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. The image shows the nebula in three colors specifically emitted by hydrogen, oxygen, and sulfur gas. The whole Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years.

2017年11月29日:M42：猎户座大星云-（M42: The Great Orion Nebula） 2017年11月29日:M42：猎户座大星云-（M42: The Great Orion Nebula）--原图下载{mtitle title="M42：猎户座大星云"/}Image Credit & Copyright: Francesco Battistella说明: 鲜少有天文景观能像着名的猎户座星云，这个邻近的恒星育婴室这么善于激发着人们的想像。这个星云的辉光云气，环拱着位在一个庞大星际分子云里的炽热年轻恒星。而在这幅主题影像里的许多丝状云气结构，事实上是激波前沿，在该处，高速移动的物质遇到慢速移动的气体。跨幅约40光年、距离约1,500光年的猎户座大星云，和太阳都位在银河系的同一道旋臂上。座落在着名猎户座内、轻易可辨的腰带三星左下方之猎户座大星云，是个肉眼可见天体。上面这幅主题照片，是在上个月使用2小时长曝光拍摄的三色影像。包括马头星云在内的整个猎户座星云複合体，在接下来的100,000年之内，会慢慢的散开来。{lamp/}原文：{mtitle title="M42: The Great Orion Nebula"/}Image Credit & Copyright: Francesco BattistellaExplanation: Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud. Many of the filamentary structures visible in the featured image are actually shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula spans about 40 light years and is located about 1500 light years away in the same spiral arm of our Galaxy as the Sun. The Great Nebula in Orion can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. The featured image, taken last month, shows a two-hour exposure of the nebula in three colors.The whole Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years.

2016年03月18日:仙后座的W形-（The W in Cassiopeia） [2016年03月18日:仙后座的W形-（The W in Cassiopeia）--原图下载](https://apod.nasa.gov/apod/image/1603/RBA_Cassiopeia_2405.jpg"onMouseOver="if (document.images)document.imagename1.src='image/1603/RBA_Cassiopeia_1024_Labeled.jpg';"onMouseOut="if (document.images)document.imagename1.src='image/1603/RBA_Cassiopeia_1024.jpg';){mtitle title="仙后座的W形"/}Image Credit &Copyright:Rogelio BernalAndreo (Deep Sky Colors)说明: 在这张彩色的併接大视野影像里，北天仙后座内的熟悉曲折W型是由5颗亮星所构成。此外，这张横跨15度富星场的天体影像，也呈现了沿着银河分布的暗云、亮星云和星团。影像中，最耀眼的是仙后座的最亮星王良四(α)；这颗橘黄巨星的温度比太阳低，但是直径却是太阳的40倍以上。它的光度是如此之高，远在240光年之外的地球夜空中看起来仍然很明亮。位在W中心、距离约550光年远的策，是一颗高速自转的大质量恒星。泛蓝的策远比太阳炽热，它发出了强烈但不可见的紫外光，电离了周围星际云气里的氢原子，当这些原子再度和电子结合时就发出了红色的Hα辐射。对位在南门二系统里的夜空观察者来说，仙后座亮星所排列成的形状依然可辨，但在4.3光年之外的他们，会认为我们的太阳是仙后座的第六亮星，更把曲折的亮星排列延伸到这张影像的左缘外头。(Shedar 王良四; Gamma Cas 策; Alpha Centauri star system 南门二系统){lamp/}原文：{mtitle title="The W in Cassiopeia"/}Image Credit &Copyright:Rogelio BernalAndreo (Deep Sky Colors)Explanation: A familiar, zigzag, W pattern in northernconstellation Cassiopeiais traced by five bright stars in this colorful and broad mosaic.Stretching about 15 degrees across rich starfields,the celestial sceneincludesdark clouds,bright nebulae, andstar clusters along the Milky Way.In yellow-orange hues Cassiopeia'salpha starShedar is a standout though.The yellowish giant star is cooler than the Sun, over 40 times thesolar diameter, and so luminous it shines brightly inEarth's night from 230 light-years away.A massive, rapidly rotating star at the center of the W, brightGamma Casis about 550 light-years distant.Bluish Gamma Cas is much hotter than the Sun.Its intense, invisible ultraviolet radiation ionizes hydrogen atoms innearby interstellar clouds to producevisible red H-alpha emission as the atoms recombine with electrons.Of course, night skygazersin the Alpha Centauri star systemwould also see the recognizable outline traced byCassiopeia's bright stars.But from theirperspective a mere 4.3 light-years away they would seeour Sun as a sixth bright star in Cassiopeia, extending the zigzagpattern just beyond the left edge of this frame.

2013年06月04日:氢原子、氧原子、硫原子光谱的猎户座大星云-（Orion Nebula in Oxygen, Hydrogen, and Sulfur） 2013年06月04日:氢原子、氧原子、硫原子光谱的猎户座大星云-（Orion Nebula in Oxygen, Hydrogen, and Sulfur）--原图下载{mtitle title="氢原子、氧原子、硫原子光谱的猎户座大星云"/}Image Credit & Copyright: C�sar Blanco Gonz�lez说明: 一些天文景观激发人的无限想像，像是邻近着名的孕育恒星的温床─猎户座大星云。星云里色彩鲜明的气体，围绕着位于广大星际分子云边缘的炙热年轻恒星。影像中，许多可见的细微结构实际是冲击波造成的，前端移动速度快的物质推挤移动速度慢的气体。猎户座大星云的跨幅约40光年，离我们约1500光年远，和太阳系一样，位在银河系相同的螺旋臂上。肉眼可见的猎户座大星云，在着名的猎户座腰带的左下方，可以找到它的蹤迹。上面这张影像，是根据发射三种不同颜色的氢原子、氧原子、硫原子光谱而合成。在未来十万年，包含马头星云的猎户座分子云複合体，将慢慢散开。{lamp/}原文：{mtitle title="Orion Nebula in Oxygen, Hydrogen, and Sulfur"/}Image Credit & Copyright: C�sar Blanco Gonz�lezExplanation: Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud. Many of the filamentary structures visible in the above image are actually shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula spans about 40 light years and is located about 1500 light years away in the same spiral arm of our Galaxy as the Sun. The Great Nebula in Orion can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. The above image shows the nebula in three colors specifically emitted by hydrogen, oxygen, and sulfur gas. The whole Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years.

2010年01月13日:宇宙中的蜘蛛及苍蝇-（The Spider and The Fly） 2010年01月13日:宇宙中的蜘蛛及苍蝇-（The Spider and The Fly）--原图下载{mtitle title="宇宙中的蜘蛛及苍蝇"/}Credit &Copyright: Troy Tsounis说明: 北天的御夫座(Auriga)拥有明亮的星云星团，包含了疏散星团M38、发射星云IC 410的蝌蚪、御夫座火焰星云IC 405、以及由IC417(偏左)和NGC1931所组成的有趣组合。扩展的IC 417看似有双眼睛，而NGC 1931细微结构，两者就像是宇宙中的蜘蛛与苍蝇。整幅影像包含了从星际云中诞生的年轻疏散星团与发光的氢气云，约莫是10,000光年。相对于较緻密NGC 1931，则是仅仅10光年宽。{lamp/}原文：{mtitle title="The Spider and The Fly"/}Credit &Copyright: Troy TsounisExplanation: Bright clusters and nebulae abound in the ancient northernconstellation ofAuriga.The regionincludes the open star clusterM38, emission nebulaIC 410 withTadpoles, Auriga's ownFlaming Star Nebula IC 405, andthis interesting pairIC 417 (lower left) and NGC 1931.An imaginative eye toward the expansiveIC 417and diminutiveNGC 1931suggests a cosmicspider and fly.About 10,000 light-years distant,both represent young, open star clusters formed in interstellarclouds and still embedded inglowing hydrogen gas.For scale, the more compact NGC 1931 is about 10 light-years across.