A total lunar eclipse on Sunday night, 27-28 September, will coincide with a rare supermoon – and the entire event will be visible, providing skies stay clear, from the UK and much of the USA. Here is how to see it.
The Moon will pass completely into the Earth’s shadow, causing a brilliant full moon to turn dim and a deep red. After more than an hour when it gradually slides into this circular shadow, or umbra, the Moon will spend 71 minutes inside it before it begins to exit and regain its customary brightness.
Such an event is always a dramatic sight, but the Moon’s diameter will be up to 14 per cent greater than usual. This is because its orbit around the Earth is not circular but an oval, or ellipse, and this eclipse happens when the Moon is at its closest point in that orbit, called perigee. Additionally, it is commonly known as the Harvest Moon because it is the full moon closest to the autumn equinox.
The spectacle will be visible from anywhere where the Moon is above the horizon at the time. This means that the whole sequence will be seen from eastern North America, South America, the Atlantic Ocean, western Europe and western Africa. (From western parts of the USA, the Moon rises during the eclipse.) You don’t need any special equipment to view it, and it is completely safe to look at, unlike a solar eclipse.
You can check out Skymania’s guide to what causes a lunar eclipse here.
Timing of the event is particularly favourable for North American observers because it all happens from mid to late evening on Sunday night. For observers in western Europe, the time difference means that it will all take place after midnight in the early hours of Monday, 28 September. Timings on the diagram for Europe are given in GMT (also known as UT) so remember that the UK is one hour ahead of this (BST) and much of Europe is two hours ahead (CET).
For astronomers, the eclipse actually begins when the Moon enters a much lighter outer shadow called the penumbra. If you could stand on the Moon facing Earth, you would see the Sun partially blocked by our planet in this penumbra. If you want to see if you can detect the slight dimming of the Moon during this stage, watch from 12.12am GMT (8.12pm EDT) when the Moon starts to enter the penumbra.
Nearly an hour later, at 1.07am GMT (9.07pm EDT) a partial eclipse begins as the Moon starts to enter the main central umbral shadow. It will lie completely within the umbra at 2.11am GMT (10.11pm EDT), marking the commencement of the total eclipse stage of the event.
It will be fascinating to see how dark the Moon becomes and how colourful it is. Its colour during an eclipse varies from orange to deep red and even grey if there is a lot of dust in the atmosphere. The colours within the shadow can vary and you will get an even better view with binoculars.
Mid-eclipse will be reached at 2.47am GMT (10.47pm EDT) and totality will end at 3.23am GMT (11.23pm EDT) when the Moon begins to exit the dark umbra. It will have completely left this dark central shadow by 4.27am GMT (12.27am EDT) and then glide on through the lighter outer shadow, or penumbra, again, leaving it completely at 5.23am GMT (01.23am EDT).
For northern hemisphere observers, the Moon moves from right to left in its orbit, so its left edge will be first to darken. Remember that the direction of its orbit is opposite the direction it appears to cross the sky, which is entirely due to the Earth’s rotation!
Here is a checklist of the key times during the eclipse, in BST (UK summer time):
Subtract 5 hours to get EDT.
Penumbral eclipse starts 01:11:46 (Moon begins to enter shadow’s pale outer zone)
Umbral eclipse starts 02:07:12 (Moon begins to enter the darkest part of shadow)
Total eclipse starts 03:11:11 (Moon is now fully within dark shadow)
Mid eclipse 03:47:09
Total eclipse ends 04:23:07 (Moon begins to leave darkest part of shadow)
Umbral eclipse ends 05:27:06 (Moon fully leaves the darkest part of the shadow)
Penumbral eclipse ends 06:22:33 (Moon leaves Earth’s shadow altogether)
If you have a camera with a telephoto or zoom lens, you might like to try to photograph the eclipse at different stages. Place your camera on a tripod, and try a range of exposures if you have manual control to get the best result.
Sadly this eclipse will not be visible if you are in eastern Asia, Japan, Australia or New Zealand, because the Moon will be below the horizon. However you should be able to catch a broadcast of it on the web! NASA is planning a live broadcast from its Marshall Space Flight Center in Huntsville, Alabama, including views of the Moon from the Griffith Observatory at Los Angeles, California. Here is the link.