我們與星星的距離

星空守護聯盟
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2019 / 6月

文‧鄧慧純 圖‧莊坤儒


“Space, the final frontier.”(宇宙,人類最後的疆界)

1966年美國科幻影集《Star Trek》,艦長Kirk以帶著詩韻的口吻述說這段全球科幻迷都熟悉的口白。靠著想像,我們早已在科幻電影中遊走各星際間,甚至接納外星人在地球定居了。但對太空的追尋、對天文的認識,源出自每位天文愛好者,無數個徹夜不眠的觀察,一個星點、一個星點地勾勒出天體的位置,一點一滴解開星空的奧秘。


鄰近玉山國家公園,座落在鹿林前山、海拔2,862公尺的鹿林天文台,隸屬於國立中央大學,擁有台灣口徑最大(1公尺)的天文望遠鏡,除了是台灣天文觀測研究重地之外,亦參與多項國際天文計畫。

台北出發,從國道3號下名間交流道,經台16線轉台21線(新中橫公路),進入玉山國家公園區域,到達鹿林前山的登山口,車行需6小時。卸下裝備,還需步行約六百公尺,才到達白色的天文台基地,是國際間少數車子到不了的天文台。

仰望星空的每一天

一路與我們同行的是天文台台長林宏欽。這一帶他熟門熟路,除了是工作場所,1990年,還是研究生時,林宏欽跟著指導教授蔡文祥參與天文台選址。走遍各地,候選地點包括大雪山、合歡山、阿里山、墾丁等地,「北台灣易受東北季風影響,南部有西南氣流,所以選在中台灣比較適合。另外,天文台通常會蓋在高山上,避開一兩千公尺低層雲氣的干擾。」林宏欽釋疑。

決定落腳在鹿林前山後,接續還有實地天文觀測調查,林宏欽回想,當初他們定期揹水揹油揹望遠鏡設備上山,觀測一周再把資料帶回分析,那是年輕時才有的衝勁。畢業後,他到竹科工作,再轉職台北市立天文科學教育館,2002年,鹿林天文台一公尺望遠鏡(LOT)正式落成,他再回到中央大學與天文台再續前緣,因此,他笑稱自己是替自己製造工作機會的案例。

天文台的生活規律且單純,除了台長林宏欽外,還有兩位觀測員林啟生和蕭翔耀,及4位原住民助理負責天文台的維運,確保一年365天只要天氣好就能觀測。

夜間觀測時間寶貴,天文台望遠鏡的使用時間是開放給國內外天文研究提交觀測計畫,經評選後分配使用觀測時段。但天候天註定,也曾碰過排定了日期,卻因為天候不佳無法觀測。溼度會損壞望遠鏡及儀器,當戶外濕度達95%便須中止觀測(國外標準為80%),我們笑稱這一行是標準的「看天吃飯」。

林宏欽解釋,台灣的天文觀測地點雖不如美國夏威夷、智利等天文台址優越,但整體來說不算太差,平均一年約有一半的天數能進行天文觀測。且位在低緯度地區,可以觀測到大部分南天區域,較高緯度國家具有優勢。此外,我們位居太平洋西側第一道觀測站點,如果美國、夏威夷的大天文台群發現某特殊目標時,鹿林天文台均能及時在第一時間確認與觀測。

觀星任務啟動

接連幾日的雨,晴空總算偷了個檔期出現。傍晚,觀測員蕭翔耀正打開天文台的天窗,準備晚上的觀測工作。

台灣的天文發展最早可追溯至日治時期,但直到中央大學天文所在鹿林前山建置一公尺望遠鏡,台灣的天文觀測有了重大突破,也多了機會加入國際合作計畫。如中美掩星合作計畫(TAOS)、美國夏威夷大學天文所及美國空軍合作的泛星計劃(Pan-STARRS)、超新星巡天計畫、EAFoN-東亞 Gamma Ray Burst (GRB)觀測網等。

多年來,天文研究的熱點之一是小行星的觀測與發現。小行星大多數分布在木星與火星之間的小行星帶,林宏欽比喻,小行星是太陽系形成過程中所剩下的一些碎屑,就像做完麵包會有很多殘餘的麵粉一般。1994年彗星撞木星的事件,讓天文學者意識到天體撞擊地球不無可能。科學家推論,恐龍滅絕的主因恐亦是小行星撞擊地球,導致全球氣候劇變所致,由此天文學家才開始關注這太空中未知的威脅。

鹿林天文台加入巡天的行列,從2002年開始,已經發現八百多顆小行星。林宏欽解釋,小行星一經發現回報給國際小行星中心,經軌道確認後,發現者可有命名權,迄今鹿林山天文台的努力,已在浩瀚的星空中留下許多關於台灣的名字,如「陳樹菊」(第 278986 號小行星)、「吳大猷」(第256892號)、「鄧雨賢」( 第255989 號)、「嘉義」( 第147918號)、「鄒族」( 第175586號)、「合歡山」(第207661號)。

命名之外,尋找小行星更重要的意義在於,未雨綢繆地防範地球遭天體撞擊。目前直徑超過一公里、可能造成致命毀滅的小行星已經有九成以上被發現,未來的任務將聚焦在數百公尺大小的小行星,這般尺寸雖不至造成人類物種絕跡,卻可能造成城市的毀滅,科學家們正集思廣益、創意發想解決的方案,蕭翔耀笑說:「所以你也可以稱我們是『地球防衛隊』。」

人與星星的連結

仰望著同一片天空,著迷於星際的無垠,還有一群業餘的天文愛好者,合歡山鳶峰是他們的聖地,每逢朔日,總能見著他們卸下車上數箱裝備,再細心組裝,等著天黑由眾星主演的星際大戲。

劉志安是當中的一員,也是台北市天文協會常務理事、臉書社團「台灣星空守護聯盟」創辦人暨版主。從小就喜歡看星星,他對星空的認識靠著跑圖書館自學而來,為了看星星,他到光學公司工作,學到許多關於望遠鏡與光學方面的知識與技術,也存錢買了自己的第一台望遠鏡。三十餘年的觀星經歷,他是亞洲第二個完成「梅西爾馬拉松」110個星體觀測者,同伴們稱他是「人體GOTO」(GOTO是望遠鏡自動導航程式),星圖都在他腦海中,「只要星星出現,我就找得到它。」

「人類對於星空的著迷是與生俱來的。」劉志安說。看著他架起望遠鏡,不借助任何輔助工具,轉個向就找到美麗的球狀或是疏散星團。透過天文望遠鏡,看到數萬光年外的星體,還可見月亮上的坑洞、木星的橫紋、土星的環,真是讓人連連驚呼的神奇體驗。劉志安還樂於分享自己的所學、所識,在鳶峰採訪時,遇到來自新加坡的朋友,他熱情地遞過鏡筒,邀請他們一窺管中的天文世界。

守護星空聯盟

星空成了劉志安生命中不可或缺的一張地圖,但從觀星意外轉向光害防制,是地圖上另一條路徑。

2013年,南投縣政府在合歡山鳶峰設置LED紀念碑,卻讓一群追星同好集結搶救岌岌可危的觀星環境。

劉志安舉紐西蘭的迪卡波小鎮為例,這個僅三、四百人的小鎮,透過光害防制,保存下美麗的星空,成為世界第一個星空保護區。認證一通過,全球的追星人都追到迪卡波,帶動當地的星空旅遊。

仿效迪卡波小鎮的思維,劉志安和同伴們從觀光切入,遊說清境當地民宿光害防制的概念,並號召觀星同好義務上山舉辦星空導覽的教育訓練,希望讓觀星旅遊的知識在當地自主發展。

劉志安帶我們拜訪了清境地區率先響應的兩間民宿:佛羅倫斯山莊和觀星園,民宿使用的燈具各有不同,但他們各自發揮巧思,如將庭園燈上方塗黑,燈具內加鋁箔,遞減燈具的瓦數,汰換燈具為霧面玻璃等等,避免光線上溢,造成天空的光害。清境地區業者也相約晚上9點後關閉戶外大型的發光體,把夜晚的舞台讓給星空。

社會輿論常認為有光才安全,劉志安舉證,過亮的燈反而容易造成炫光及視覺死角,他們並非要關掉所有的燈,重點是「適切的照明」。路燈的燈面只要垂直面下,就能減少30~40%的光線射向天空,照明也該有夜間模式,調整亮度,不僅節能,還能保護眼睛。

官方看見這群觀星人的決心,也投入相關戶外照明公約規範制定。2018 年 7 月,由南投縣政府、清境觀光協會及天文團體合作,向國際暗天協會( International Dark-Sky Association, IDA )遞出申請,規範從鳶峰前兩公里處至合歡北峰登山口,長度約15公里的範圍,為「合歡山國際暗空公園」。

其實清境的星空早已吸引鄰近香港、澳門、東南亞等國的朋友定期到台灣報到。台灣的地利之便,一下飛機,只需兩個多小時車程,就能到達海拔2,000公尺以上的高山觀星,是光害嚴重的香港、新加坡追星人所欣羨的。

去年年底,國際暗空組織IDA已來台灣考察,台灣有望繼韓國永陽螢火蟲保護區、日本西表石垣國家公園,成為亞洲第3個國際暗空公園。

今年4月1日,劉志安在臉書上宣告自工作退休,這不是愚人節的玩笑,才53歲的他早早退休,要全心守護星空,為孩子保留住一片美麗的星空;他擔心現有的成果,若少了人繼續添柴火,「火滅了,要再起就很難了。」他說。

仰望著繁星,與我們相距如此遙遠的光年,它們的美麗身影,成為人類文明綺麗的神話;人類對其無盡的好奇,也開啟了我們宇宙的旅程。走一趟觀星的旅程,我們發現,我們與星空的距離,不如想像的遠。                                           

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EN

Between Us and the Stars

The Taiwan Dark-Sky Preservation Alliance

Cathy Teng /photos courtesy of Chuang Kung-ju /tr. by Phil Newell

“Space, the final frontier.” These are the words, familiar to science fiction fans the world over, that opened each epi­sode of the TV show Star Trek, poetically intoned by Captain James T. Kirk. Through the power of imagination, in science fiction films we have long traveled among the stars and even accepted aliens who settle on planet Earth. But the explor­ation of space and an understanding of astronomy really start with individual amateur astronomers, who have spent countless sleepless nights observing the universe. One star at a time, they have pieced together the positions of heavenly bodies, and bit by bit they have uncovered the mysteries of space.


The Lu­lin Observatory stands at an altitude of 2862 meters on Front Mt. Lu­lin, just outside the boundary of Yu­shan National Park. Operated by National Central University, it has Taiwan’s largest-diameter optical telescope—the Lulin One-meter Telescope (LOT). Besides being a bastion of astronomical observations in Taiwan, it is also involved in many international astronomy programs.

It takes a six-hour drive from Taipei to reach the trailhead for the observatory. After unloading our gear, we still have to hike about 600 meters to get to the white observa­tory buildings; this is one of the few observatories in the world that cannot be reached by motor vehicle.

Stargazing year round

Observatory director Lin Hung-chin accompanies us ­every step of the way. He is deeply familiar with this locale not only because it is his current workplace, but also because in 1990, while still a graduate student, Lin worked with his faculty advisor, Professor Tsay Wean-shun, on the search for an observatory site. “Northern Taiwan is strongly impacted by the northeasterly seasonal monsoons, while in southern Taiwan there are southwesterly airflows, so we decided that the most appropriate site would be in central Taiwan,” explains Lin. “In addition, observatories are normally built on high mountains, to avoid inter­ference from clouds at 1000 to 2000 meters.”

Life at the observatory is simple and highly regulated. Besides Director Lin Hung-chin, there are also two observers, Lin Chi-­sheng and ­Hsiao Hsiang-­yao, as well as four Aboriginal assistants who are responsible for maintaining operations at the observatory, ensuring that so long as the weather is good, observations can be made 365 nights a year.

Nighttime observation time is very precious. Use of the LOT is open to researchers inside and outside Taiwan, who tender observation plans; timeslots are assigned after evalu­ation of these plans. But after all, the weather is variable, so it may easily happen that someone is given a timeslot on a specific day, but observations can’t be made because of poor weather. This line of work is a classic case of “making one’s living at the mercy of the elements.”

Lin Hung-chin explains that overall, Taiwan’s conditions for astronomical observation are not bad, with observations being possible on about half the days of the year. Moreover, because the observatory is located at a low latitude, the visible area of sky includes most of the southern celestial hemisphere, which is an advantage compared to high-latitude countries. In addition, says Lin, Lu­lin is located in the first line of observation stations along the western rim of the Pacific Ocean, so if the big astronomical arrays in Hawaii detect some special target, the Lu­lin Observatory can confirm and observe it in a timely manner.

Besides observing the stars, a fringe benefit of being stationed here is that you can often see “majestic views.”

After a night of observing, the sun is just rising from behind Yu­shan. ­Hsiao Hsiang-­yao does not stop to admire the sunrise, but rather takes us to look westward into the distance. He says that when the weather is good it is possible to see the shadow of the earth, and indeed along the western horizon there appears a thin layer of indescribable blue that is intoxicatingly beautiful.

The main focus of stargazing

The development of astronomy in Taiwan can be traced back to the era of Japanese rule, but the building of the LOT by National Central University’s Institute of Astro­nomy represented a major breakthrough for astronomical observa­tion in Taiwan. It also created numerous opportuni­ties to take part in international collaborative programs, such as the Taiwan‡America Occultation Survey (TAOS), the Pan-STARRS program (in colloboration with the Institute for Astronomy at the University of Hawaii and the US Air Force), the Taiwan Supernovae Survey, and the East Asian Gamma Ray Burst Follow-up Network (EAFoN).

For many years now, the detection and observation of asteroids has been a focal point of astronomical research. Asteroids are mainly distributed in a belt between Ju­piter and Mars. Lin Hung-chin explains that asteroids are fragments left behind from the formation of the solar system, comparing them to flour left over after baking a loaf of bread. The crashing of a comet into Jupiter in 1994 alerted astronomers to the pos­sibil­ity that something in space could crash into the Earth. It was then that astronomers started to keep an eye out for unknown threats from space.

The Lulin Observatory joined the ranks of observa­tories scanning the skies for asteroids, and since 2002 has discovered more than 800 of these celestial objects. In the vast reaches of space there are already many asteroids with names related to Taiwan, such as “Chen­shu­chu” (Asteroid No. 278986), “Wu­da­you” (No. 256892), “Deng­yu­shian” (No. 255989), “Chiayi” (No. 147918), “Tsou” (No. 175586), and “Hehuanshan” (No. 207661).

Besides naming asteroids, a more important reason for searching them out is to take preventive measures in the event that Earth looks likely to be struck by an object from space. In the future, the main focus will be placed on asteroids with a diameter of 100 meters and above. Although an impact of this size would not mean the extinction of human life on Earth, it could cause the destruction of a city. Scientists are already devoting thought and creativity to devising responses to such an eventuality. ­Hsiao Hsiang-­yao laughs: “This is why you can also call us ‘guardians of Earth.’”

Links between man and the stars

There is also a community of amateur astronomers who scan the same skies and are equally fascinated by the boundlessness of interstellar space.

One of these enthusiasts is Liu Chih-an, president of the Tai­pei Amateur Astronomers Association and also founder and webmaster of the Facebook group the Taiwan Dark-Sky Preservation Alliance. He has enjoyed stargazing since childhood, and taught himself about the night sky by going to the library to read about astronomy. In order to better view the stars, he took a job at an optics company, where he learned a great deal about optics and telescopes. In over 30 years of space observation, he has become only the second observer in Asia to complete the “Messier Marathon” of sighting 110 heavenly bodies in one night. His colleagues call him “a human GoTo” (a GoTo is a type of telescope mount and software that can auto­matic­ally point a telescope at a selected celestial object)—he’s got a map of the stars in his brain, and says: “So long as the star appears, I can find it.”

“Mankind’s fascination with space is human nature,” says Liu Chih-an. We watch as he sets up a tele­scope without any assistive tools, and turns it to find beautiful globular star clusters or scattered open star clusters. To the naked eye, many heavenly bodies are just points of light, but through the telescope one can see the craters on the moon, the various zones and belts of Jupiter’s atmosphere, and the rings of Saturn, while celestial objects tens of thousands of light years away become visible; it’s an amazing experience. Liu is also happy to share his know­ledge with others. When we went with him to Yuan­feng Peak on Mt. He­huan, he met some visitors from Singa­pore, and generously invited them to look into the eyepiece of his telescope and explore the astronomical realm.

Protecting the darkness

The starry skies have become an indispensable map in the life of Liu Chih-an. But it has been another road al­together on this map that has unexpectedly taken him from observing the stars to combating light pollution.

In 2013, the Nan­tou County Government placed an LED commemorative marker on Yuan­feng Peak. This led to the banding together of a group of astro­nomy afi­cion­ados to save Mt. Hehuan’s stargazing environ­ment from the imminent threat of light pollution.

Liu points to the example of the small town of Lake Te­kapo in New Zealand as a successful example of the benefits of preventing light pollution. This little town, with only 300‡400 residents, has become part of the world’s first “dark-sky reserve.” After gaining this certifica­tion, it began to receive visits from stargazers from all over the world, driving local “astro­tourism.”

Inspired by the ideas behind Lake Tekapo, in the name of promoting tourism Liu Chih-an and his colleagues began to educate local homestays in the Qing­jing area of Nan­tou’s Ren’ai Township about preventing light pollution. They also called on volunteers from the stargazer community to offer training in guiding visitors through the night sky, hoping that know­ledge related to astro­tourism would develop autonomously in the local area.

Liu Chih-an takes us to visit two homestays: Florence Resort Villa and Starry House. The two homestays use different lighting equipment, but each has devised clever ideas to reduce light pollution, such as painting the outsides of their garden lamps black or reducing the wattage of their lights, in order to leave the night stage to the stars.

Public opinion often has it that a place is safe only if it is well lit, but Liu counters that excessive lighting can cause glare and blind spots. He and his co-campaigners by no means want to turn out all the lamps: their main focus is on “appropriate lighting.”

When the Nan­tou County Government saw the determination of this group of stargazers, it also committed itself to observing norms set by relevant outdoor lighting conventions. In July of 2018 Nan­tou County, in co­opera­tion with the Cing­jing Tourism Association and astro­nomy groups, applied to the International Dark-Sky Associ­ation (IDA) for certification for a proposed He­huan Mountain Dark-Sky Park.

In late 2018 the IDA came to Taiwan for a fact-finding visit. There is hope that Taiwan will be the third country in Asia to have a dark-sky park, following on from the Yeong­yang Firefly Eco Park in South Korea and the Iriomote‡­Ishigaki National Park in Japan.

On April 1, 2019, Liu Chih-an announced on Facebook that he would retire from his job. This was no April Fools’ Day prank. He is retiring at the early age of 53 to devote himself entirely to preserving the beauty of the night sky for future generations. He is worried about the durability of current successes, for if there is no one to feed the fire in the future, “the flame will go out, and it will be very difficult to light it again,” he says.

Looking up at the vast sky filled with stars, so many light years distant from us, their beautiful forms became the focus of enchanting myths at the origins of civilization, and humans’ limitless curiosity about them has initiated our modern journey into the cosmos. But when we took a stargazing tour of our own, we discovered that the distance between us and the stars is not as far as you might imagine.                        

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