千年等一回—日環(huán)食歸來(lái)

Ring of fire' solar eclipse to occur Sunday, May 20

日環(huán)食將于5月20日出現(xiàn)

A partial solar eclipse photographed by the joint Japanese-American Hinode satellite. (Hinode/XRT)

被日美聯(lián)合衛(wèi)星“日之出”所拍攝到的一顆日偏食

(Space.com) Skywatchers in East Asia and the western United States should circle Sunday (May 20) on their calendars. That's when a solar eclipse will block out most of the sun, leaving a spectacular "ring of fire" shining in the sky for observers located along the eclipse's path.

東亞和美國(guó)西部的觀測(cè)者應(yīng)該在日歷上圈上周日(五月20日)這天。這一天日食會(huì)遮住太陽(yáng)的大部分，只留下一個(gè)壯觀的“火環(huán)”在天空閃爍，位于日食運(yùn)行軌跡上的觀測(cè)者都有機(jī)會(huì)觀測(cè)到這一景象。

The event is what's known as an annular solar eclipse -- from the Latin "annulus," meaning "little ring" -- and its full glory should be visible from much of Asia, the Pacific region and some of western North America, weather permitting. At its peak, the eclipse will block about 94 percent of the sun's light.

這一景象就是我們所說(shuō)的日環(huán)食，拉丁語(yǔ)“annulus”意思為“小環(huán)”。如果天氣條件允許，位于亞洲，太平洋地區(qū)及西北美一些地區(qū)的觀測(cè)者將有幸目睹這一壯觀景象。日食最大時(shí)會(huì)遮住94%的太陽(yáng)光。

Other parts of the United States and Canada will still see a partial solar eclipse, without being treated to the ring of fire effect, though the East Coast will miss the event since the sun will have set before it begins. The eclipse will occur in the late afternoon or early evening of May 20 throughout North America, and May 21 for observers in Asia.

雖然東海岸的觀測(cè)者會(huì)因?yàn)樘?yáng)在日食開始前就日落而錯(cuò)過(guò)這次日食，但美國(guó)和加拿大其他地區(qū)的觀測(cè)者仍然可以看到日偏食，只不過(guò)不是火環(huán)狀。日食將在北美5月20日的傍晚時(shí)分或晚上出現(xiàn)。

Solar eclipses occur when the moon comes between Earth and the sun, casting a shadow on our planet. When the moon lines up perfectly with the sun and blots out all of its light, the result is a total eclipse. Partial eclipses cover only part of the sun's face.

當(dāng)月亮運(yùn)行到地球和太陽(yáng)之間時(shí)，日食就會(huì)出現(xiàn)，并在地球上投下月影。當(dāng)月亮和太陽(yáng)完全成一條直線并遮住太陽(yáng)時(shí)，就形成了日全食。日偏食即月亮只遮住了部分太陽(yáng)。

Annular eclipses are similar to total eclipses in that the moon lines up with the sun dead-on. But in this case, the moon is close to apogee -- the farthest point from Earth in its elliptical orbit around our planet -- so it's a smidge too small in the sky to cover the solar disk completely. As a result, a ring of bright sunlight will still blaze around the moon's circumference.

日環(huán)食與日全食的形成是相似的，即在月亮與太陽(yáng)完全成一條直線時(shí)才會(huì)發(fā)生。但在這種情況下，月亮接近最高點(diǎn)——位于它橢圓軌道上的最遠(yuǎn)點(diǎn)。而這時(shí)它的表面積太小不足以完全遮住太陽(yáng)表面，就形成了一個(gè)在月亮周圍發(fā)光的日光環(huán)。

Like other types of solar eclipses, annular eclipses are spectacular but potentially dangerous skywatching events. Care must be taken to observe them properly, or serious and permanent eye damage -- including blindness -- could result.

和其他種類的日食一樣，日環(huán)食是很壯觀的景象，但同時(shí)對(duì)觀測(cè)者來(lái)說(shuō)卻也存在潛在危險(xiǎn)。觀測(cè)者要十分注意以正確的方式進(jìn)行觀測(cè)，否則眼睛會(huì)被嚴(yán)重灼傷或?qū)е掠谰檬鳌?/p>

Warning: Never look directly at the sun, either with telescopes or binoculars without the proper filters.

提醒：不要直接用眼睛觀看，要使用望遠(yuǎn)鏡或者無(wú)過(guò)濾片雙筒鏡。

To safely observe the May 20 annular eclipse, you can buy special solar filters to fit over your equipment, or No. 14 welder's glass to wear over your eyes. Do NOT use standard sunglasses or any kind of homemade sun-shading contraption.

安全起見，為觀測(cè)5月20日出現(xiàn)的日環(huán)食，你可以購(gòu)買特殊的太陽(yáng)濾鏡并將其安裝在觀測(cè)設(shè)備上或者佩戴No. 14 welder's眼鏡。不要使用普通太陽(yáng)鏡或者任何自制的遮陽(yáng)裝置。

The safest and simplest technique is perhaps to watch the eclipse indirectly with the solar projection method. Use your telescope, or one side of your binoculars, to project a magnified image of the sun's disk onto a shaded white piece of cardboard.

最安全和最簡(jiǎn)單的方法可能就是通過(guò)太陽(yáng)投影來(lái)觀測(cè)日食。用你的望遠(yuǎn)鏡或者雙筒鏡的一面在一塊白色的紙板上投影一個(gè)放大的太陽(yáng)圖像。

The image on the cardboard will be safe to view and photograph. Be sure to cover the telescope's finder scope or the unused half of the binoculars, however, and don't let anybody look through them.

觀察和拍攝紙板上的圖像是安全的。確保要遮住望遠(yuǎn)鏡的可視范圍部分或者雙筒鏡不使用的一面，不要讓任何人通過(guò)望遠(yuǎn)鏡和雙筒鏡來(lái)觀察。