Home > General Astronomy > Total Lunar Eclipse 15 June 2011

Total Lunar Eclipse 15 June 2011

The first total eclipse of the Moon of 2011 occurs this Wednesday evening, 15 June 2011, and it will be the longest lunar eclipse in over a decade. However the views from the UK (and Europe) will be constrained by the fact that the Moon will be below the horizon for much of the eclipse, and will rise fully eclipsed, or in some cases even coming out of eclipse. It’s still worth having a look though: just try to find somewhere with a very low and clear SE horizon, as this will be the direction in which the Moon will rise, and it will be in eclipse only while it is VERY low (only a few degrees above the horizon).

Lunar Eclipse, December 21, 2010, by Jiyang Chen

A lunar eclipse occurs when the Moon, in its orbit around the Earth, passes into the Earth’s shadow, as cast by the Sun. You might imagine that this would happen once every lunar orbit, or once a month. That it does not is due to the fact that the Moon’s orbit around the Earth is tilted by around 5 degrees compared with the Earth’s orbit around the Sun. So in most orbits the Moon passes above or below the Earth’s shadow.

However, once in a while (there are at least two lunar eclipses each year) the orbital planes will align so that the Moon passes through the Earth’s shadow, sometimes just grazing it, in which case we get a partial lunar eclipse, and at other times passing right through the shadow, when we get a total lunar eclipse.

The Earth’s shadow has two distinct regions, forming two concentric circles [correction, the shadow is two cones, not circles – need to think in 3D! (see comments)]: the inner, darker, part of the shadow is called the umbra, and objects within this part of the shadow receive no direct light from the Sun. The outer, lighter, part of the shadow is called the penumbra, and objects within this part of the shadow can receive direct light from the Sun, but part of the Sun’s disk will be obscured by the Earth, and so less light than normal falls on the object.

The umbra and the penumbra

For the lunar eclipse of 15 June 2011 the Moon will pass very deeply into the darker umbra, making this an especially dark – and long – eclipse.

There are several distinct phases of a lunar eclipse, as the Moon travels through the penumbra and umbra. For this lunar eclipse the total time during which the Moon is at least partially in the Earth’s shadow is 219 minutes, and 100 minutes of this is spent entirely within the umbra, i.e. in total eclipse.

The phases of the 15 June 2011 total lunar eclipse (via NASA's eclipse website)

These phases are given the names: P1, the time when the Moon’s disk enter the penumbra; U1, the time when the Moon’s disk enters the umbra; U2, the time when the entirety of the Moon’s disk is within the umbra; U3, the last time when the entirety of the Moon’s disk is within the umbra; U4, the last time when part of the Moon’s disk is within the umbra; and P4, the last time when part of the Moon’s disk is within the penumbra.

The timings for these instances are well known. In the following table are: the timings for P1, U1, U2, U3, U4, and P4; the time of greatest eclipse (i.e. where the Moon is closest to the centre of the umbra); and the local times of moonrise for a variety of places around the UK

Eclipse Contact Contact Description Time (UT) Time (BST) Moonrise Time (BST) (UK Location)
P1 Penumbral Eclipse Begins 17:24:34 UT 18:24
U1 Partial Eclipse Begins 18:22:56 UT 19:22
U2 Total Eclipse Begins 19:22:30 UT 20:22
Greatest Eclipse 20:12:37 UT 21:12 21:12 (Channel Islands)
21:14 (London)
21:26 (Cardiff)
21:33 (Manchester)
21:56 (Belfast)
21:58 (Glasgow)
U3 Total Eclipse Ends 21:02:42 UT 22:02
22:19 (Orkney)
21:23 (Shetland)
U4 Partial Eclipse Ends 22:02:15 UT  23:02
P4 Penumbral Eclipse Ends 23:00:45 UT  00:00

UT = Universal Time = GMT
BST = British Summer Time = GMT+1

As you can see, the UK is far from ideally placed to view this total lunar eclipse, but the further south and east you are the better your chances of seeing something. The Moon will rise well past U2 across the UK, and everywhere except the Channel Islands and SE England it will rise well past greatest eclipse. Indeed in the north of Scotland the Moon will rise after the total eclipse phase ends (i.e. past U3).

Observers in the Channel Islands and in the SE of England will have around 50 minutes of total eclipse to observe although the Moon will still only be a few degrees above the horizon at U3), and here in Glasgow I’ll have about 4 minutes between moonrise and U3!

While in total eclipse no direct sunlight will fall on the Moon, but we will still be able to see it illuminated a dull red colour. How can this be, if there is no sunlight shining on it to light it up? It is due to the fact that the Sun’s light is refracted, or bent, through the Earth’s atmosphere. The red light from the Sun’s spectrum is refracted the most, and so it is this light that will illuminate the Moon during a lunar eclipse. In effect, the light you will see on the Moon is the combined light from all the sunrises and sunsets on Earth, being focused onto the Moon by the lensing effect of the Earth’s atmosphere.

A detailed information sheet for this eclipse (and others) is available (pdf) on the NASA Eclipse website.

  1. June 14, 2011 at 20:45

    Russia – Moscow
    Eclipse Begins at 21:23 hrs on June 15, 2011 (Local Time) – Visible
    Total Lunar Eclipse begins at 22:22 hrs – Visible
    Total Lunar Eclipse ends at 00:03 hrs – Visible
    Eclipse Ends at 01:02 hrs on June 16, 2011 – Visible

    • June 14, 2011 at 21:15

      A small correction to your times. Moscow is on MSD which is UT+4 (or GMT+4), and so the following are the correct timings for Moscow:

      Eclipse begins P1 = 17:24:33 UT = 21:24 MSD
      Proper darkening begins U1 = 18:22:55 UT
      Full eclipse begins U2 = 19:22:29 UT = 23:22 MSD
      Full eclipse ends U3 = 21:02:41 UT = 01:03 MSD
      Last instant of proper darkening U4 = 22:02:14 UT = 02:02 MSD
      Eclipse ends P4 = 23:00:44 UT = 03:01 MSD

      You’re right though, it is visible from Moscow :-)

  2. steve
    June 15, 2011 at 10:49

    The shadow is a (two) cones not circles.

    • June 15, 2011 at 12:05

      You’re quite right, I was thinking too 2D!

  3. ash
    June 15, 2011 at 15:56

    Is it visible from the middle east?

    • June 15, 2011 at 16:21

      The middle east is the best place to see it! Don’t know what time zone you’re in but the timings above are GMT so you can work it out from there.

  4. clo
    June 15, 2011 at 17:42

    will i be able to see it from the coast in east anglia

    • June 15, 2011 at 18:00

      Yes! One of the best places in the UK to see it (assuming you’ve got clear skies). Look SE just after 21:00 when the Moon will be rising in greatest eclipse. You’ll have about an hour to see it in full eclipse. However it’ll be very low on the horizon (no more than a couple of finger widths with you hand held at arms length) so you’ll need a very clear (ideally coastal) SE horizon, which you may well have! Good luck, it’s cloudy here…

  5. Anton
    June 15, 2011 at 19:21

    What time will you we able to see the eclipse in South Africa?

    • June 15, 2011 at 19:27

      Hi Anton, SA is GMT+2 at the moment, isn’t it? So just add 2 hours on to each of the times above for the times with you. i.e. total eclipse begins 21:22SAST, ends 23:02SAST. You’ll get good views, but remember to look NE not SE like my article says; I was adopting a northern hemisphere bias!

      • June 15, 2011 at 20:47

        the times above are in BST. (GMT+1)..South Africa is in GMT+2

  6. June 15, 2011 at 19:54

    when is the best time for me to see the eclips in glasgow

    • June 15, 2011 at 20:24

      I’m in Glasgow and I think the clouds will thwart us! Even if it clears the Moon doesn’t rise till 2158, with only four minutes remaining of the total eclipse. Got another hour or so as it comes out of eclipse when it’ll be a partial eclipse, but you’ll need a v good SE view.

  7. Annelize
    June 15, 2011 at 20:40

    Where can I find the moon in the sky from Cape Town, at this moment?

  8. June 15, 2011 at 20:41

    wow this was amazing saw it, i thought omg the world is definately coming to an end tonight. i was totally unaware of this. it looked different from my expected image of an ECLIPSE. however it was nice and amazing, funny thing is when i saw it i was on ma way to the LAN and i had felt ma room, i kept staring at it untikl i was far from ma room at res. and i had to buzz ma sister to tell her that her that there is an eclipse, and the first thing that came to my mind was TWILIGHT the movie.

  9. Nicola
    June 15, 2011 at 20:56

    Hi Steve! Just been reading up on the lunar eclipse. I’m in Kirkwall so I’m guessing the moon will rise after the full eclipse? It’s quite cloudy at the moment, but I’ll aim to have a look around 22:20 to see if I can catch a glimpse of the partial. Hope you’re well!

    • June 15, 2011 at 21:03

      Hey Nicola! Yes, pretty poor chance of seeing much up in Orkney, but you never know!

  10. A D Seetohul
    June 15, 2011 at 20:57

    Very fine view here in Mauritius!!!!! Really fabulous….impressive…..dramatic!!!!!!!!!!!!

  11. serdar
    June 15, 2011 at 21:18

    hi..from turkey…ı love obscuration

    • June 15, 2011 at 21:20

      You’re getting a great view from Turkey! Perfect location for observing this lunar eclipse

  12. jennifer
    June 15, 2011 at 21:49

    i was waiting very much indeed but i missed it i feel sad..am in a area with high mountains(turkey.fethiye)n i didnt think i need to go out to the sea for a view…just learnt that very late..
    time to sleep though am sad:(

  13. ronnie
    June 15, 2011 at 22:10

    helo im from glasgow :D did anyone in glasgow see it ??? all i saw was red sky :/

    • June 15, 2011 at 22:29

      No sign of it, I’m afraid. Clouds and a poor horizon spoiled my chances of seeing anything.

  14. moses magadza and andra
    June 15, 2011 at 22:15

    fabulous view from katutura in namibia in southern africa

    • June 15, 2011 at 22:29

      Wonderful: Namibia is one of my very favourite places!

  15. June 15, 2011 at 22:46

    hi..from Indonesia…Perfect location for observing this lunar eclipse….-_-

  16. allison
    June 16, 2011 at 01:26

    will you be able to see it in the u.s and what time will the peak be if i live in indiana

    • allison
      June 16, 2011 at 01:47

      nvr mind, i looked on another website and the us will not be able to see it. now im bummed. :( (teary face)

    • June 16, 2011 at 07:56

      Unfortunately the eclipse was all over by the time the Moon rose over the US. There’s another total lunar eclipse on 10 December but that’s an early morning one just before sunrise. The next one after that (and it’s a good one for the Americas) is 15 April 2014!

  17. Missy
    June 16, 2011 at 01:43

    can’t see it from my place….its raining!!

  18. Ashley
    June 16, 2011 at 02:40

    i missed it tonight….. i live in the U.S. can you see it from here? and i heard there is another lunar eclipse on December 10, 2011…… what time would that be for that lunar eclipse? (in December in NY)

  19. Joanna
    June 16, 2011 at 03:40

    can you see it in New Mexico tonight??

    • June 16, 2011 at 07:56

      No, unfortunately the eclipse was all over by the time the Moon rose over the US. There’s another total lunar eclipse on 10 December but that’s an early morning one just before sunrise. The next one after that (and it’s a good one for the Americas) is 15 April 2014!

  20. Sait
    June 16, 2011 at 15:24

    it was gr8 yestday Steve, i really watched the whole scene, from the partial up to the total eclipsed. The sky was very clear here in Botswana and was in a gr8 angle, my bed is just on the window so i just moved the curtain and enjoyed the view from bed.

  21. June 16, 2011 at 16:15

    hello.
    I watched the eclipse in the Poland, Biala Podlaska. I have not seen the beginning, but the end was about 23:50 local time. It was very dark. In maximum phase the moon wasn’t visible.

  22. June 16, 2011 at 17:23

    remarkable event in light of what is also happening now on the sun.

  23. June 16, 2011 at 18:32

    It was the first full-fledge eclipse I saw. Before that eclipses werent so visible in our region

  24. June 17, 2011 at 00:37

    Nice, love your diagrams!

  25. June 17, 2011 at 02:15

    go girl :
    wow this was amazing saw it, i thought omg the world is definately coming to an end tonight. i was totally unaware of this. it looked different from my expected image of an ECLIPSE. however it was nice and amazing, funny thing is when i saw it i was on ma way to the LAN and i had felt ma room, i kept staring at it untikl i was far from ma room at res. and i had to buzz ma sister to tell her that her that there is an eclipse, and the first thing that came to my mind was TWILIGHT the movie.

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