Astronomical Info / 天文資訊 > Special Events / 特別項目 > Total Lunar Eclipse of May 26th, 2021 | 2021 年 5 月 26 日之月全食 [Refresh 更新]

Quick info 快速資訊: Eclipse time (total and partial phases) at Hong Kong 香港可見月食 (全、偏食) 時間 : 2021/05/26 18:56 - 20:52 HKT

Quick links 快速連結:
- Live webcast 網上直播 - Information about the eclipse 是次月食資料
- Local (HK) circumstances 本地 (香港) 情況 - Future lunar eclipses 未來月食
- Lunar eclipse basic knowledge 月食基礎知識 - More eclipse info 更多日月食資訊

The eclipse has ended. 月食已結束。

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。

Provider 提供者 Channel / Notes 頻道 / 備註
- HKO and others [Click for more locations in HK] 香港天文台與其他機構 [按此顯示香港更多地方]

Below video from HK Space Museum 以下顯示的為香港太空館頻道

- Griffith Observatory
- Central Weather Bureau (Taiwan) 台灣中央氣象局
- Weather News Japan (in Japanese 日文網頁)
- Vixen
- Virtual Telescope

<Back to Top 返回頁頂>

Information about the eclipse 是次月食資料

The total lunar eclipse on May 26 is the first one in more than two years. In this episode, viewers in eastern and central Oceania will be able to observe the eclipse in its entirety. Viewers in most of Asia will experience the event at moonrise, while those in the Americas will see the eclipse at moonset. The eclipse is not visible at all in Europe or Africa.

This time, the moon will just be deep enough in Earth's umbra to produce a total eclipse. As a result, the total phase is rather short and will only last for less than 15 minutes. The partial phases extend the eclipse by about 1.5 hours, each before and after totality.

5 月 26 日的月全食是超過兩年來首次。是次月食中,大洋洲東部及中部將可見整個月食過程;亞洲大部分地區將見帶食月出,而美洲則可見帶食月落。是次月食於歐洲及非洲並不可見。

月全食期間月球只僅僅完全進入地球本影中,因此全食時間頗短,只維持少於 15 分鐘。月偏食則於全食前後各約 1.5 小時間可見。

Map courtesy of NASA 月食圖由美國太空總署提供

The following shows some general details about the eclipse:

下表列出是次月食的一般性資料 :

Eclipse series and characteristics
Saros series number 沙羅序列號碼 121 (occurring at descending node 降交點月食)
Member in the series 序列中次數 56 out of 84 | 84 次中的第 56 次
Gamma 伽馬數 0.4774 earth radii 地球半徑
Time in UTC/HKT on May 26
5 月 26 日時間 (世界協調時 / 香港時間)
P1 - Moon enters Earth's penumbra (penumbral eclipse starts)
P1 - 月球進入地球的半影 (半影月食開始)
08:47 UTC; 16:47 HKT
U1 - Moon enters Earth's umbra (partial eclipse starts)
U1 - 月球進入地球的本影 (初虧,月偏食開始)
09:44 UTC; 17:44 HKT
U2 - Moon fully enters Earth's umbra (total eclipse starts)
U2 - 整個月球進入地球的本影 (食既,月全食開始)
11:11 UTC; 19:11 HKT

Greatest eclipse

11:18 UTC; 19:18 HKT
U3 - Moon starts to leave Earth's umbra (total eclipse ends)
U3 - 月球開始離開地球的本影 (生光,月全食結束)
11:25 UTC; 19:25 HKT

U4 - Moon fully leaves Earth's umbra (partial eclipse ends)
U4 - 整個月球離開地球的本影 (復圓,月偏食結束)

12:52 UTC; 20:52 HKT
P4 - Moon fully leaves Earth's penumbra (penumbral eclipse ends)
P4 - 整個月球離開地球的半影 (半影月食結束)
13:49 UTC; 21:49 HKT
Information at greatest eclipse
食甚 (食分最大) 時資料
Time 時間 11:18 UTC; 19:18 HKT
Penumbral Magnitude (P) and Umbral Magnitude (U) 半影食分 (P) 和本影食分 (U) P: 1.9540; U: 1.0095

All places that can observe this eclipse (i.e., with the moon above the horizon) will experience the aforementioned events in 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

It will be rather difficult to observe the total phase of this eclipse In Hong Kong, as the Moon will have been almost completely obscured by the Earth's shadow by moonrise. Due to the short duration of the totality, the lunar altitude will only be at 5 degrees when total eclipse ends. The moon will continue to pick up altitude after totality, and will be at around 22 degrees from the horizon at the end of the partial phase.

Due to the low lunar altitude during the eclipse, it is best viewed in locations completely not obscured towards the east-southeast.

是次月全食較難於香港看到。月出時,月球已幾乎完全進入地球的本影;而由於全食時間短暫,至全食完結時月球仰角只得 5 度。其後月球會繼續上升,偏食完結時月球仰角約為 22 度。


The details are summarized in the following table:

詳細資料整理如下 :

Event for Hong Kong
Time in HKT on May 26
5 月 26 日香港時間
Lunar Altitude and Azimuth
Moonrise (partial eclipse in progress)
月出 (月偏食進行中)
18:56 Altitude 高度 : -1°
Azimuth 方位角 : 112° (ESE 東南偏東)
Moon fully enters Earth's umbra (total eclipse starts)
整個月球進入地球的本影 (食既,月全食開始)
19:11 Altitude 高度 : 2°
Azimuth 方位角 : 114° (ESE 東南偏東)
Greatest eclipse
19:18 Altitude 高度 : 4°
Azimuth 方位角 : 115° (ESE 東南偏東)
Moon starts to leave Earth's umbra (total eclipse ends)
月球開始離開地球的本影 (生光,月全食結束)
19:25 Altitude 高度 : 5°
Azimuth 方位角 : 115° (ESE 東南偏東)

Moon leaves Earth's umbra (partial eclipse ends)
月球離開地球的本影 (復圓,月偏食結束)

20:52 Altitude 高度 : 22°
Azimuth 方位角 : 126° (SE 東南)
Moon leaves Earth's penumbra (penumbral eclipse ends)
月球離開地球的半影 (半影月食結束)
21:49 Altitude 高度 : 31°
Azimuth 方位角 : 136° (SE 東南)
Information at greatest magnitude for Hong Kong
Type 類型 Total 月全食
Time 時間 19:18 HKT
Direction of shadow relative to the Moon 地球影子方向 (相對於月球)

Leaving from the top right 由月球右上方離開

<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) :

Date (UTC)
日期 (世界協調時)
Eclipse type
Eclipse type at HK
Time of greatest eclipse in HK
2021/11/19 Partial 月偏食 P: 2.0720; U: 0.9742 Partial 月偏食 17:37 (moonrise 月出)
2022/05/16 Total 月全食 P: 2.3726; U: 1.4137 --- ---
2022/11/08 Total 月全食 P: 2.4143; U: 1.3589 Total 月全食 18:59
2023/05/05 Penumbral 半影月食 P: 0.9636; U: -0.0457 Penumbral 半影月食 2023/05/06 01:23
2023/10/28 Partial 月偏食 P: 1.1181; U: 0.1220 Partial 月偏食 2023/10/29 04:14
2024/03/25 Penumbral 半影月食 P: 0.9557; U: -0.1325 --- ---
2024/09/18 Partial 月偏食 P: 1.0372; U: 0.0848 --- ---
2025/03/14 Total 月全食 P: 2.2595; U: 1.1784 --- ---
2025/09/07 Total 月全食 P: 2.3440; U: 1.3619 Total 月全食 2025/09/08 02:11
2026/03/03 Total 月全食 P: 2.1838; U: 1.1507 Total 月全食 19:33

* 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。

The partial lunar eclipse later this year will also be visible in Hong Kong at moonrise.


<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.


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.




  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。


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: Sun Oct 01 2023 13:28:36 HKT
Last Modified 最近修訂日期: Mon Jul 24 2023