Super Total Lunar Eclipse 21st January 2019

A total lunar eclipse is when the Moon passes into the Earth’s total shadow, or umbra. Lunar eclipses occur on a full Moon night when the Sun, Earth and Moon are aligned in a straight line or almost straight line in space. Anyone on the night-side of the Earth at the time of the eclipse can see it.

Can I see the Lunar Eclipse in the UK?

Yes, but you will need favourable weather, and be able to get up from around 3:30am until 5:45am on Monday morning. Below is a chart showing where the total lunar eclipse is visible, shaded in red. The lighter the shading denotes a partial eclipse.

In the UK, the Moon will rise on Sunday afternoon at about 4pm GMT in the North Western sky. From about 3:30am on Monday morning, the Moon will gradually dim as the Moon falls into the shadow of the Earth with totality at about 5:15am, depending on your location.

During the total phase of the eclipse, those under otherwise dark skies away from city lights should notice a distinct darkening of their surroundings as more stars emerge in the sky. The dimming of the Moon should present a beautiful photo opportunity as the Moon will have dimmed from -12Mag to -6. Dim stars around the Moon will be visible and the Milky Way should appear in the sky.

A lunar eclipse can be enjoyed with the naked eye, but optical aids, like binoculars or a telescope, offer the chance to better investigate craters on the Moon and the subtle shading and colouring of the eclipse.

If you plan to watch more than just a few minutes of the eclipse, seasoned observers recommend dressing warmer than you think necessary and bringing food and hot drinks. A chair or blanket will make the experience more enjoyable.

Why is this a Super Lunar Eclipse?

While early January is when the Earth is closest to the Sun in its annual journey, the Moon is also closer to Earth and will be 7.5% bigger than the Moon’s average, angular size in the sky. That makes this Super Eclipse particularly helpful for photographers and observers.

Diagram of the various stages of a lunar eclipse

The various stages of a total lunar eclipse, fully described

1. Moon enters penumbra – The shadow cone of the Earth has two parts: a dark, inner umbra, surrounded by a lighter penumbra. The penumbra is the pale outer portion of the Earth’s shadow.
   • Although the eclipse begins officially at this moment, this is in essence an academic event. You won’t see anything unusual happening to the Moon — at least not just yet. The Earth’s penumbral shadow is so faint that it remains invisible until the Moon is deeply immersed in it. We must wait until the penumbra has reached roughly 70 percent across the Moon’s disk. For about the next hour the Full Moon will continue to appear to shine normally although with each passing minute it is progressing ever deeper into the Earth’s outer shadow.
2. Penumbral shadow begins to appear – Now the Moon has progressed far enough into the penumbra so that it should be evident on the Moon’s disk. Start looking for a very subtle light shading to appear on the Moon’s left portion. This will become increasingly more evident as the minutes pass, the shading appearing to spread and deepen.
   • Just before the Moon begins to enter the Earth’s dark umbral shadow the penumbra should appear as an obvious smudge or tarnishing of the Moon’s left portion.
3. Moon enters umbra – The Moon now begins to cross into the Earth’s dark central shadow, called the umbra. A small dark scallop begins to appear on the Moon’s left-hand (eastern) limb. The partial phases of the eclipse begin; the pace quickens and the change is dramatic. The umbra is much darker than the penumbra and fairly sharp-edged.
   • As the minutes pass the dark shadow appears to slowly creep across the Moon’s face. At first the Moon’s limb may seem to vanish completely inside of the umbra, but much later, as it moves in deeper you’ll probably notice it glowing dimly orange, red or brown.
   • Notice also that the edge of the Earth’s shadow projected on the Moon is curved. Here is visible evidence that the Earth is a sphere, as deduced by Aristotle from lunar eclipses he observed in the 4th Century BC. Almost as if a dimmer switch was slowly being turned down, the surrounding landscape on Earth and deep shadows of a brilliant moonlit night begin to fade away, at least for viewer’s away from bright lights.
4. 75 percent coverage – With three-quarters of the Moon’s disk now eclipsed, that part of it that is immersed in shadow should begin to very faintly light up, similar to a piece of iron heated to the point where it just begins to glow.
   • It now becomes obvious that the umbral shadow does not involve complete darkness. Using binoculars or a telescope, its outer part is usually light enough to reveal lunar seas and craters, but the central part is much darker, and sometimes no surface features are recognizable. Colours in the umbra vary greatly from one eclipse to the next, Reds and grays usually predominate, but sometimes browns, blues and other tints are encountered.
5. Less than five minutes to totality – Several minutes before (and after) totality, the contrast between the remaining pale-yellow sliver and the ruddy-brown coloration spread over the rest of the Moon’s disk may produce a beautiful phenomenon known to some as the “Japanese Lantern Effect.”
6. Total eclipse begins – When the last of the Moon enters the umbra, the total eclipse begins. How the Moon will appear during totality is not known. Some eclipses are such a dark gray-black that the Moon nearly vanishes from view. At other eclipses it can glow a bright orange.The reason the Moon can be seen at all when totally eclipsed is that sunlight is scattered and refracted around the edge of the Earth by our atmosphere. To an astronaut standing on the Moon during totality, the Sun would be hidden behind a dark Earth outlined by a brilliant red ring consisting of all the world’s sunrises and sunsets.
   • The brightness of this ring around the Earth depends on global weather conditions and the amount of dust suspended in the air. A clear atmosphere on Earth means a bright lunar eclipse. If a major volcanic eruption has injected particles into the stratosphere during the previous couple of years, the eclipse is very dark.
7. Middle of totality – The Moon is now shining anywhere from 10,000 to 100,000 times fainter than it was just a couple of hours ago.
   • Since the Moon is moving well to the south of the centre of the Earth’s umbra, the gradation of colour and brightness across the Moon’s disk should be such that its upper portion should appear darkest, with hues of deep copper or chocolate brown. Meanwhile, its lower portion — that part of the Moon closest to the outer edge of the umbra — should appear brightest, with hues of reds, oranges and even perhaps a soft bluish-white.
   • Observers away from bright city lights will notice a much greater number of stars than were visible before the eclipse began. The Moon will be the constellation of Aries, the Ram, with the beautiful little Pleiades Star Cluster, shining 25 degrees to the Moon’s east (left). Your fist on an outstretched arm covers about 10 degrees of sky.
   • The darkness of the sky is impressive for those in the countryside. The surrounding landscape takes on a somber hue. Before the eclipse, the Full Moon looked flat and one-dimensional. During totality, however, it will look smaller and three-dimensional, like some weirdly illuminated ball suspended in space.
   • Before the Moon entered the Earth’s shadow, the temperature on its sunlit surface hovered at 130 degrees Celsius. Since the Moon lacks an atmosphere, there is no way that this heat can be retained from escaping into space as the shadow sweeps by. Now, in shadow, the temperature on the Moon has dropped to 99 degrees below zero Celsius. That’s a drop of 229 degrees Celsius in less than 90 minutes!
8. Total eclipse ends – The emergence of the Moon from the shadow begins. The first small segment of the Moon begins to reappear, followed again for the next several minutes by the Japanese Lantern Effect.
9. 75 percent coverage – Any vestiges of coloration within the umbra should be disappearing now. From here on, as the dark shadow methodically creeps off the Moon’s disk it should appear black and featureless.
10. Moon leaves umbra – The dark central shadow clears the Moon’s right hand (western) limb.
11. Penumbra shadow fades away – As the last, faint shading vanishes off the Moon’s right portion, the visual show comes to an end.
12. Moon leaves penumbra – The eclipse “officially” ends, as it is completely free of the penumbral shadow.

Timings for the lunar eclipse of 21st January 2019

(Courtesy of CalSky).

How to take photos of the Lunar Eclipse

1. The first thing to do is to find a suitable location to view the eclipse. It is unlikely that just looking out your window or standing in your back garden will be suitable, especially for urban areas. Check where the Moon will be in the sky at the beginning and end of the eclipse and choose a location where you can see the Moon, without obstruction.
2. Charge your camera batteries fully, and format your memory card, check for dust on the lens you will be using and the sensor.
3. If using a telephoto/zoom lens, the more you zoom in to view the Moon the faster the Moon will appear to move in the sky, this will limit how slow a shutter speed you can use and continue to get a sharp image. On the night before the eclipse, test your setup by photographing the Moon at your preferred location, and adjust your ISO, shutter speed and focal length to suit your lens, and the brightness of the Moon.
4. Many photographers like to do a time lapse of the lunar eclipse using a wide angle lens, a sturdy tripod and a beautiful background location. There are a number of apps, like PhotoPills, that can help you frame your shot and know where the Moon will start and finish in the frame for a good composition.
5. A dew heater for your lens is highly recommended to avoid the lens fogging up while you are outside at night. These can be purchased from any local telescope dealer and will require an independent power source to run them.
6. Wrap up warm with gloves, a warm hat and coat, with windproof trousers too. It can get cold standing around outside for long periods.
7. Check the weather forecast!
8. If you are using a tripod, turn off your lens or camera image stabilisation. Leaving the IS on can result in blurry images as the IS can jump around.
9. Your focusing point should be set to infinity if you have that option on your lens, otherwise, set your focus point very carefully using a zoomed in Live View as any accidental adjustment can result in out of focus background stars.
10. When you have a focus you are happy with, set the focus to manual mode and do not adjust the focus or zoom.
11. Use a self timer of 3 seconds or a remote control to take the photo, to reduce any camera shake. You can also turn on mirror lock up mode in the settings.
12. Review your images after your take them. The beauty of digital photography is that you can adjust and fine tune your photos as the eclipse happens. You will need to increase the exposure time or ISO as the Moon reaches totality and gets quite dark in comparison to a full Moon.

Webcasts of the Lunar Eclipse of 21st January 2019

Slooh Situation Room

Greenwich Observatory