• A. 天氣資訊
• B. 天文資訊
• C. 熱帶氣旋
• D. 本站活動
• E. 其他資訊
• F. 搜尋本站

主頁 現時生效警告 分區天氣 雨量 紫外線指數 華南海域天氣報告 香港天氣預測 天氣照片 天氣圖 衛星 / 雷達圖像 華南天氣要素圖

香港天文資料 世界時間 世界各大城市太陽資訊 特別天文事件 日食日期和數字 月食日期和數字 日月食問與答 日食計算機

最新熱帶氣旋資訊 天文台之熱帶氣旋資訊 官方熱帶氣旋路徑資料 熱帶氣旋信號機率 各站預測路徑圖 熱帶氣旋資料庫 熱帶氣旋尋找工具 重要熱帶氣旋回顧 影響香港氣旋之風速數據 厄爾尼諾-南方濤動動態 西北太平洋: ASCAT 風場圖 西北太平洋: 風 / 分析 西北太平洋: 駛流圖 參考資料: 熱帶氣旋名稱 參考資料: 蒲福氏風級 參考資料: 熱帶氣旋分類 參考資料: 熱帶氣旋發佈機制 有關熱帶氣旋之連結

實時天氣資訊圖 本站選舉 * 一觸即發遊戲 * 月氣候展望比賽

其他氣象連結 合作網站 關於我們 本站聲明 * 網誌 "望天打卦"

Astronomical Info / 天文資訊 > Special Events / 特別項目 > Partial Lunar Eclipse of November 19th, 2021 | 2021 年 11 月 19 日之月偏食 [Refresh 更新]

Quick info 快速資訊: Eclipse time (partial phase) at Hong Kong 香港可見月食 (偏食) 時間 : 2021/11/19 17:38 - 18:47 HKT

Live webcast 網上直播

Please click on the links below for live webcast and descriptions of the event. All links (on the left panel) redirect you to external websites and open in new windows.

請按下列連結以觀看網上直播及相關資訊。所有 (左方) 連結連至第三者網站並以新視窗開啟。

<Back to Top 返回頁頂>

Information about the eclipse 是次月食資料

A partial lunar eclipse will occur on November 19. Viewers in North America and extreme eastern Asia at higher latitudes will be able to observe the eclipse in its entirety. Viewers in the rest of Asia and Oceania will experience the event at moonrise, while those in South America, western Africa and western Europe will see the eclipse at moonset. The eclipse is not visible at all in western Asia, eastern Europe or central/eastern Africa.

The umbral magnitude of this eclipse is in excess of 0.97, making it almost a total event. As most of the Moon will enter Earth's umbra, the partial phase of this eclipse lasts almost 3.5 hours.

一次月偏食將於 11 月 19 日發生。北美洲及亞洲東端的高緯度地區將可見整個月食過程；亞洲其餘大部分地區及大洋洲將見帶食月出，而南美洲、西非及西歐則可見帶食月落。是次月食於亞洲西部、東歐及非洲中東部並不可見。

是次月食的本影食分達 0.97，幾乎成為一次全食。由於月球絕大部分於月食期間進入地球本影，因此偏食時間達接近 3.5 小時之久。

The following shows some general details about the eclipse:

下表列出是次月食的一般性資料 :

All places at which this eclipse can be observed (i.e., with the moon above the horizon) will experience the aforementioned events at the times indicated above.

所有可以看見月食的地點 (即月球於地平線上) 均會在上述時間看見該等事件。

<Back to Top 返回頁頂>

Local (HK) circumstances 本地 (香港) 情況

Unfortunate to the observers in Hong Kong, the eclipse will have passed its greatest point by moonrise. At locations completely free of obstacles to the east-northeast, observers will be able to see an eclipse magnitude of approximately 0.7 to 0.8. The moon will gradually recede from the Earth's umbra as it rises above the horizon, and will only be at an altitude of 14 degrees when partial eclipse ends.

For optimal viewing, observers are advised to select a location with no obstacles to the east and east-northeast.

對香港的觀測者而言，較可惜的是當晚月出時已過食甚時間。在東北偏東方完全沒有阻擋的位置，觀測者可見食分約為 0.7 至 0.8。隨著月球上升，它將逐漸移離地球本影，至偏食完結時月球仰角只得 14 度。

是次月食的最佳觀賞位置為東及東北偏東方完全沒有阻擋的地區。

The details are summarized in the following table:

詳細資料整理如下 :

<Back to Top 返回頁頂>

Future lunar eclipses 未來月食

Lunar eclipses in the next five years (click on the date to see the visible areas for that eclipse):

未來五年的月食資料 (請按下日期以觀看月食可見範圍) :

* P represents penumbral magnitude while U represents umbral magnitude.
* P 和 U 分別代表半影食分和本影食分。

There will be two total lunar eclipses in 2022, with the one in November visible in Hong Kong.

2022 年將出現兩次月全食，其中 11 月的一次於香港可見。

<Back to Top 返回頁頂>

Lunar eclipse basic knowledge 月食基礎知識

The following information is quoted from Wikipedia. 以下資料摘自維基百科。

A lunar eclipse occurs whenever the Moon passes through some portion of the Earth's shadow. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, there is always a full moon the night of a lunar eclipse. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes.

月食，又作月蝕，是當月球運行進入地球的陰影（本影部份）時，原本可被太陽光照亮的部份，有部份或全部不能被直射陽光照亮，使得位於地球的觀測者無法看到普通的月相的天文現象。月食發生時，太陽、地球、月球恰好或幾乎在同一條直線上，因此月食必定發生在滿月的晚上（農曆十五、十六、或十七）。地球陰影位於地球公轉軌道面（黃道面）內，此平面與月球軌道面（白道面）並不重合，黃白道面交角約5度；大多數滿月時，月球不在黃道面內，而是或偏北或偏南，不在地球陰影內，因此並不是每個滿月時，都發生月食。每年發生至少兩次月食。

The shadow of the Earth can be divided into two distinctive parts: the umbra and penumbra. Within the umbra, there is no direct solar radiation. However, as a result of the Sun's large angular size, solar illumination is only partially blocked in the outer portion of the Earth's shadow, which is given the name penumbra.

A penumbral eclipse occurs when the Moon passes through the Earth's penumbra. The penumbra does not cause any noticeable darkening of the Moon's surface, though some may argue it turns a little yellow. A special type of penumbral eclipse is a total penumbral eclipse, during which the Moon lies exclusively within the Earth's penumbra. Total penumbral eclipses are rare, and when these occur, that portion of the Moon which is closest to the umbra can appear somewhat darker than the rest of the Moon.

A partial lunar eclipse occurs when only a portion of the Moon enters the umbra. When the Moon travels completely into the Earth's umbra, one observes a total lunar eclipse. The Moon's speed through the shadow is about one kilometer per second (2,300 mph), and totality may last up to nearly 107 minutes. Nevertheless, the total time between the Moon's first and last contact with the shadow is much longer, and could last up to 3.8 hours. The relative distance of the Moon from the Earth at the time of an eclipse can affect the eclipse's duration. In particular, when the Moon is near its apogee, the farthest point from the Earth in its orbit, its orbital speed is the slowest. The diameter of the umbra does not decrease much with distance. Thus, a totally-eclipsed Moon occurring near apogee will lengthen the duration of totality.

The Moon does not completely disappear as it passes through the umbra because of the refraction of sunlight by the Earth's atmosphere into the shadow cone; if the Earth had no atmosphere, the Moon would be completely dark during an eclipse. The red colouring arises because sunlight reaching the Moon must pass through a long and dense layer of the Earth's atmosphere, where it is scattered. Shorter wavelengths are more likely to be scattered by the small particles, and so by the time the light has passed through the atmosphere, the longer wavelengths dominate. This resulting light we perceive as red. This is the same effect that causes sunsets and sunrises to turn the sky a reddish colour; an alternative way of considering the problem is to realise that, as viewed from the Moon, the Sun would appear to be setting (or rising) behind the Earth.

The amount of refracted light depends on the amount of dust or clouds in the atmosphere; this also controls how much light is scattered. In general, the dustier the atmosphere, the more that other wavelengths of light will be removed (compared to red light), leaving the resulting light a deeper red colour. This causes the resulting coppery-red hue of the Moon to vary from one eclipse to the next. Volcanoes are notable for expelling large quantities of dust into the atmosphere, and a large eruption shortly before an eclipse can have a large effect on the resulting colour.

月食有三種類型：

• 月全食：當整個月球進入地球的本影內時，在其前後均會發生月偏食與半影月食。
  
• 月偏食：當月球只有部份進入地球的本影時，在其前後均會發生半影月食。
  
• 半影月食：此時月球只是掠過地球的半影區，造成月面的光度極輕微減弱，所以較不易為人注意。
  

由於地球的本影比月球大得多，這也意味著在發生月全食時，月球會完全進入地球的本影區內，所以不會出現月環食這種現象。

月食過程：

1. 半影食始：月球剛剛和半影區接觸，這時月球表面光度略為減少，但肉眼較難覺察。
   
2. 初虧：月球由東緣慢慢進入地影，月球與地球本影第一次外切。
   
3. 食既：月球進入地球本影，並與本影第一次內切。
   
4. 食甚：月圓面中心與地球本影中心最接近的瞬間，此時前後月球表面呈紅銅色或暗紅色。（原因：大陽光經過地球大氣層時發生折射，使光線向內側偏折，但每種光的偏折程度不一樣（色散），紅光偏折程度最大，最接近地球陰影，映在月球上；此外，由於大氣層的灰塵及雲的含量與位置不同，光線偏折程度會有不同，因此月全食時的月球是暗紅、紅銅、或橙色的。同樣的道理，由於大氣層的折射，朝陽與夕陽不是白色的，而根據高度因為大氣折射程度不同，呈現橙色或紅色。）
   
5. 生光：月球在地球本影內移動，並與地球本影第二次內切。
   
6. 復圓：月球逐漸離開地球本影，與地球本影第二次外切。
   
7. 半影食終：月球離開半影，整個月食過程正式完結。

月偏食沒有食既、生光過程，食甚也只表示最接近地球陰影的時刻。

Please read the Wikipedia article for more. 欲得到更多資料，請瀏覽相關條目。

<Back to Top 返回頁頂>

More eclipse info 更多日月食資訊

For more information on eclipses, visit our "Eclipse Q&A" section (total 3 pages) and "Eclipse Dates and Numbers - Lunar Eclipse".

如欲得知更多有關日月食的資訊，請到本網的 "日月食問與答" 一節 (共三頁) 和 "月食日期和數字"。

Eclipse times and information are based on Eclipse Predictions by Fred Espenak, NASA's GSFC. NASA's lunar eclipse page: here.

Last Accessed 最近訪問日期: Sat Mar 22 2025 14:04:12 HKT
Last Modified 最近修訂日期: Mon Jul 24 2023