秋分: 卡拉尼什巨石阵上空的日行迹

秋分: 卡拉尼什巨石阵上空的日行迹

ByNASA中文

2022年9月18日 Analemma over the Callanish Stones Image Credit & Copyright: Giuseppe Petricca Explanation: If you went outside at the same time every day and took a picture that included the Sun, how would the Sun’s position change? A more visual answer to that question is an analemma, a composite image taken from the same spot at the same time over the course of a year. The featured analemma was composed from images taken every few days at noon near the village of Callanish in the Outer Hebrides in Scotland, UK. In the foreground are the Callanish Stones, a stone circle built around 2700 BC during humanity’s Bronze Age. It is not known if the placement of the Callanish Stones has or had astronomical significance. The…

西西里上空的获月

西西里上空的获月

ByNASA中文

2022年9月15日 Harvest Moon over Sicily Image Credit & Copyright: Dario Giannobile Explanation: For northern hemisphere dwellers, September’s Full Moon was the Harvest Moon. Reflecting warm hues at sunset it rises over the historic town of Castiglione di Sicilia in this telephoto view from September 9. Famed in festival, story, and song Harvest Moon is just the traditional name of the full moon nearest the autumnal equinox. According to lore the name is a fitting one. Despite the diminishing daylight hours as the growing season drew to a close, farmers could harvest crops by the light of a full moon shining on from dusk to dawn. Harvest Full Moon 2022: Notable Submissions to APOD Tomorrow’s picture: pixels in space 西西里上空的获月 影像提供与版权: Dario Giannobile 说明: 对于北半球的住民来说，9月的满月是丰收的获月。在这幅摄于9月9日的长焦镜头里像里，它在日落时，带着温暖的色调从历史悠久的西西里堡小镇后方升起。以节日、故事和歌曲而著称的获月，是最接近秋分的满月之传统名称，而它显然是这轮满月很贴切的称号。因为随着生长季节接近尾端，白昼渐短，但农民仍然可以在黄昏到黎明彻夜普照的月光下收割庄稼。 2022年获月:…

2021年的天空

2021年的天空

ByNASA中文

2022年3月21日 The Sky in 2021 Image Credit & Copyright: Cees Bassa (Netherlands Institute for Radio Astronomy) Explanation: What if you could see the entire sky — all at once — for an entire year? That, very nearly, is what is pictured here. Every 15 minutes during 2021, an all-sky camera took an image of the sky over the Netherlands. Central columns from these images were then aligned and combined to create the featured keogram, with January at the top, December at the bottom, and the middle of the night running vertically just left of center. What do we see? Most obviously, the daytime sky is mostly blue, while the nighttime sky is mostly black. The twelve light bands crossing the night sky are caused by…

美丽的春分日落

美丽的春分日落

ByNASA中文

2022年3月20日 A Picturesque Equinox Sunset Image Credit & Copyright: Roland Christen Explanation: What’s that at the end of the road? The Sun. Many towns have roads that run east – west, and on two days each year, the Sun rises and sets right down the middle. Today is one of those days: an equinox. Not only is today a day of equal night (“aequus”-“nox”) and day time, but also a day when the sun rises precisely to the east and sets due west. Featured here is a picturesque road in northwest Illinois, USA that runs approximately east -west. The image was taken during the March Equinox of 2015, and shows the Sun down the road at sunset. In many cultures, this March equinox is taken…

南极的日出

南极的日出

ByNASA中文

2021年10月5日 Sunrise at the South Pole Image Credit & Copyright: Martin Wolf (U. Wisconsin), IceCube Neutrino Obs., NSF; ht: Alice Allen Explanation: Sunrise at the South Pole is different. Usually a welcome sight, it follows months of darkness — and begins months of sunshine. At Earth’s poles, it can take weeks for the Sun to rise, in contrast with hours at any mid-latitude location. Sunrise at a pole is caused by the tilt of the Earth as it orbits the Sun, not by the rotation of the Earth. Although at a pole, an airless Earth would first see first Sun at an equinox, the lensing effect of the Earth’s atmosphere and the size of the solar disk causes the top of the Sun to appear…

获月的迹线

获月的迹线

ByNASA中文

2021年9月23日 Harvest Moon Trail Image Credit & Copyright: Mike Cohea Explanation: Famed in festival, story, and song the best known full moon is the Harvest Moon. For northern hemisphere dwellers that’s a traditional name of the full moon nearest the September equinox. Seen from Saunderstown, Rhode Island, planet Earth, this Harvest Moon left a broad streak of warm hues as it rose through a twilight sky over the Newport Bridge. On September 20 its trail was captured in a single 22 minute exposure using a dense filter and a digital camera. Only two days later the September equinox marked a change of season and the beginning of autumn in the north. In fact, recognizing a season as the time between solstice and equinox, this Harvest…

秋分那天的地球

秋分那天的地球

ByNASA中文

2021年9月22日 Equinox on a Spinning Earth Image Credit: Meteosat 9, NASA, earthobservatory, Robert Simmon Explanation: When does the line between night and day become vertical? Today. Today is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth’s terminator — the dividing line between day and night — becomes vertical and connects the north and south poles. The featured time-lapse video demonstrates this by displaying an entire year on planet Earth in twelve seconds. From geosynchronous orbit, the Meteosat 9 satellite recorded these infrared images of the Earth every day at the same local time. The video started at the September 2010 equinox with the terminator line being vertical. As the Earth revolved…