數量多且定時出現,是雙子座流星雨得以名列年度大流星群之一的最大特色,也讓它幾乎年年都成為臺北天文館天象指數★★★的「精彩級」天象。
雙子座流星雨概況
雙子座流星雨一般活動時間是在12月7日至17日,今年極大期預計落在12月15日凌晨0:45,但有前後2~3小時的誤差,預測之每小時數量最多可達120顆左右。此群流星速度慢(~每秒35公里),亮度中等,偶爾會出現火流星。
因雙子座屬冬季黃道星座,於12月中旬的天黑後已在東邊地平附近,午夜時升至天頂,天亮前才移到西方天空中,整夜均可見到。此外因逢眉月,因此臺灣地區最佳觀測時間約為12月14日21時眉月西沈後至12月15日凌晨天亮前的這段時間,恰好涵蓋極大期預測時間,觀測條件相當棒。
欣賞流星雨不需任何特殊器材,只要挑選視野開闊、光害稀少的地方,用肉眼觀賞即可。另12月已入冬,天氣寒冷,在室外,尤其是高山上觀賞流星雨要小心保暖,並提防露水或結霜。並注意觀賞時盡量勿開啟明亮燈光,以免打擾他人欣賞。
除了雙子座流星雨本身外,雙子座中的紅色戰神—火星、獅子座中有著美麗光環的土星、英仙座中體積已比太陽還大的荷瑪彗星(17P/Holmes),以及四季中最燦爛的冬季星空,都是不錯的觀測目標,不妨順便欣賞一下吧!
http://www.tam.gov.tw/forecast/2007/h07120701.htm
How to observe the 2007 Geminids
To maximize the chances of seeing meteors, choose a dark site. "'Dark' means at least 40 miles from a major city," Bakich says. And you can leave your telescope home. "You don't need optical aid (a telescope or binoculars) to observe the Geminids. Your eyes alone work best for meteor showers because they don't restrict your field of view." That said, binoculars will help you follow any long-lived smoke trails.
Suggested gear includes a lawn chair, lots of warm clothing, cookies or fruit, and a warm, non-alcoholic beverage. Alcohol interferes with the eye's dark adaptation as well as the visual perception of events.
After sunset, a meteor watcher should face generally east and look halfway up. Looking east before moonset also places the Moon behind you. Glancing around won't hurt anything. Once the Moon sets, move your gaze to straight overhead.
http://www.astronomy.com/asy/default.aspx?c=a&id=6374
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