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Total Lunar Eclipse, 21st December 2010
Submitted: Tuesday, 19th October 2010 by Mike Salway
The Total Lunar Eclipse on December 21st, 2010 will be visible in its entirety for all of North America, and will be in progress at Moonrise for Australians, New Zealand and east-Asia. It will be visible at Moonset for most of Europe and Africa, and will not be visible at all for South and East Africa, the Middle East or South Asia. For Australians and New Zealanders, the eclipse will be in progress during Moon rise (after sunset on the 21st December). Generally, the further East you are, the more of the eclipse you'll see. The further west you are in Australia, more of the eclipse will be finished by the time the moon rises for you. The below map shows visually where the eclipse can be seen from around the world (large version here). Read on below for what it means to you, more information, local timings, and hints and tips for viewing and photographing the eclipse. We'd love you to register at the IceInSpace Forums and don't be afraid to ask if you have any questions. To see images and read reports after the event (and to post yours too!), check regularly in the Observational Astronomy and Solar System sections.
Use the links below to find the information you're after:
What is a Lunar Eclipse?A Lunar Eclipse occurs when part or all of the Moon passes into Earth's shadow. This doesn't happen every Full Moon though, because the Moon's orbit is actually tipped about 5° with respect to Earth's orbit around the Sun. This means that during most Full Moon's, the Moon is actually above or below the Earth's plane and therefore not in the shadow of the Earth. The diagram below shows the basic geometry of a Lunar Eclipse. The Earth's shadow has two parts - the Umbra, which is the darker inner shadow, and the Penumbra, which is the fainter outer shadow. Please contact me if you'd like a larger version of the diagram below.
Two to four times per year, the Moon passes through some or all of Earth's penumbral and umbral shadow, causing one of the three types of Lunar Eclipse: Penumbral Lunar EclipseA Penumbral Lunar Eclipse is when the Moon passes into the Earth's penumbral shadow. This type of eclipse accounts for 35% of all Lunar Eclipses. The difference in visibility on the moon during this phase is very subtle and difficult to observe. Partial Lunar EclipseA Partial Lunar Eclipse is when only a part of the Moon passes into the Earth's umbral shadow. This type of eclipse accounts for 30% of all Lunar Eclipses. During this phase, a "chunk" or portion of the moon goes into shadow. Total Lunar EclipseA Total Lunar Eclipse is when the Moon passes completely into the Earth's umbral shadow, described as "Totality". Total Lunar Eclipses account for the other 35% of all lunar eclipse. These are the most spectacular type of Lunar Eclipse, as during totality the moon can take on a range of striking colours. Scattered sunlight passes deep through the Earth's atmopshere which filters out most of the blue light. The remaining light renders the Moon in shades of red, orange, yellow and brown - depending on the amount of dust and volcanic ash in the Earth's atmosphere. All Total Lunar Eclipses start with a Penumbral, followed by a Partial and then the Total Lunar Eclipse. Finally, a Partial followed by a Penumbral completes the event. All types of Lunar Eclispe are completely safe to observe with the unfiltered and unaided eye. The images below show what each of the types of Lunar Eclipse can look like.
When and Where Can I See it?The Total Lunar Eclipse on December 21st, 2010 will be visible in its entirety for all of North America, and will be in progress at Moonrise for Australians, New Zealand and east-Asia. It will be visible at Moonset for most of Europe and Africa, and will not be visible at all for South and East Africa, the Middle East or South Asia. For Australians and New Zealanders, the eclipse will be in progress during Moon rise (after sunset on the 21st December). Generally, the further East you are, the more of the eclipse you'll see. The further west you are in Australia, more of the eclipse will be finished by the time the moon rises for you. Use the table below to find the city closest to you, which shows the timings for the various phases of the Eclipse. The times are given in local time for that city. The altitude of the moon at that phase is shown, and if it's in red, it means it's below the horizon and that phase will not be visible in that city.
Viewing GuideLunar Eclipses (unlike Solar Eclipses) are completely safe to observe with the unfiltered and unaided eye - no special equipment is needed. Telescope observations can be done, however at full moon the lack of contrast due to absence of shadow regions means that visible features are limited. Binoculars can help improve the view, giving you more magnification and intensifying the colouration. A pair of 7x50 or 10x50's are best - any larger than that and you'll need a steady tripod to mount them on. Sometimes a Total Lunar Eclipse is best viewed without any optical aid, and just lying under the stars watching the change as the Moon first gets slightly darker (penumbral phase), then starts to get eaten away (partial phase), finally turning deep red as it enters totality. For something different, try predicting the Danjon Brightness Scale - a measure of the colour and brightness during totality. For Australians and New Zealanders, the Eclipse will be in progress as the Moon rises, so it will be important to find a location with a good Easterly aspect where the Moon can be viewed down low. This can also present some added challenges for photography, but can also add some fantastic foreground elements to the scene if done correctly. However you choose to view the Eclipse, we'd love to hear about your experiences! Please register and post your observing reports in the Observational Astronomy section. Photography / Imaging GuidePhotographing a Lunar Eclipse is quite easy, and doesn't need any special equipment or filters. The whole event can last quite a while as well, so you've got time on your hands. From the start of the partial phase, you have approximately an hour as the shadow gradually creeps across the Moon until it covers the whole Moon. Totality lasts approx 1.5 hours, followed by another hour of partial as the shadow moves off the Moon. But it can also depend on where you live - for Australians and New Zealanders, the Eclipse will be in progress as the Moon rises, so it will be important to find a location with a good Easterly aspect where the Moon can be viewed down low. This can also present some added challenges for photography, but can also add some fantastic foreground elements to the scene if done correctly. If you're using digital, this gives you time to preview your images and make sure your composition and exposure is correct, and to re-shoot if needed. There are many ways to photographically present a Total Eclipse of the Moon. Following are a few ideas. These ideas will be focused on digital imaging - if you still use film then the techniques will be similar, but you lose the ability to preview your shots and re-shoot if needed! 1) Short Focal Length Telescope ViewAs mentioned before, high-resolution high-magnification views through a telescope are likely to be quite disappointing due to the lack of contrast during a full moon. The same applies if you're trying to image the Eclipse using normal high-resolution imaging techniques. If you're using a telescope, the best results will be obtained where you can fit the whole Moon in the Field Of View (FOV) of your telescope and imaging device. Some examples of this could include:
You can take images during various stages of the eclipse to present a final composite showing all phases on the same image, or you could simply use a single totality image (for example) to present the Moon during a Total Lunar Eclipse. An example of both of these methods is seen in the images above. You could also take a sequence of images over the entire eclipse (for example, every 10 minutes), resize them down and present an animated gif showing a "movie" of the Moon diving into shadow, entering Totality and then coming out again. An example showing an animated gif like this, is one from Fred Espanek in January 2000. 2) Long Focal Length Camera ViewUsing a normal digital camera sitting on a tripod, choose your longest zoom setting or longest focal length lens (using a DSLR) and frame the Moon. Take test shots to check your composition and exposure. Make sure you use the histogram function on your camera to ensure that you're not clipping either end of the histogram (not overexposing or underexposing). Zoom in on the preview screen to check that your focus is sharp. Most cameras should be able to get an autofocus lock on a bright object like the Moon, so focus shouldn't be too much of an issue. If your camera is able, once you've got a focus lock, change the focus to Manual so that it doesn't change between shots. As the weather gets colder and the Moon increases in altitude, the focal point may change so it may be worth re-checking focus once every hour or two. For a normal digital camera (not a SLR/DSLR) change the focus to the "infinity" setting and leave it there. The exposure will need to change during the phases of the eclipse as the Moon dives into shadow. During totality, a longer exposure such as a few seconds may be needed while a fraction of a second is all that's needed when the Moon is not in shadow. Keep your ISO setting low (eg: ISO100) to minimise the noise. It's also worth bracketing your shots or simply check the image afterwards and re-shoot if necessary. During haze, fog or high cloud you will need to increase the exposure. You can take images during various stages of the eclipse to present a final composite showing all phases on the same image, or you could simply use a single totality image (for example) to present the Moon during a Total Lunar Eclipse. An example of both of these methods is seen in the images above. You could also take a sequence of images over the entire eclipse (for example, every 10 minutes), resize them down and present an animated gif showing a "movie" of the Moon diving into shadow, entering Totality and then coming out again. An example showing an animated gif like this, is one from Fred Espanek in January 2000. 3) Widefield Camera ViewThis technique involves a digital camera with a wife field of view or short focal length lens, and would give the most natural "eyeball view" of the Eclipse. Simply sit the camera on a tripod and take an image of the Moon in it's natural environment. The challenge is to present it with beautiful foreground interest - so put some thought into where you're going to photography from. A view of the Moon above some houses and trees might not be as spectacular as the Eclipsed Moon rising above the ocean or interesting architecture or structure. Be creative. Visit the location beforehand and take some test landscape shots so you can be sure the image will look aesthetically pleasing. Landscape photography is an art in itself, so practising will help! Use a slow focal ratio (stop down the lens), for example f/9 or higher, to ensure that both the foreground and the Moon are captured in sharp focus. Another interesting and beautiful way to present widefield images of the Eclipse is to take a sequence of images over the duration of the Eclipse (every 5-10 minutes) and make a composite of the Moon images over the foreground. It's important to keep the camera steady and make sure the tripod doesn't move throughout the night so you can ensure accurate position of the Moon when making the composite. Fred Espanek has used this technique with great success by taking multiple exposures on the same piece of film. Some of his examples of this technique are here and here. You can see his full gallery on his website to get some more ideas. I also used this technique during the August 28th 2007 Total Lunar Eclipse; you can see my result here. My Lunar Eclipse Gallery is here.
However you choose to photograph the Eclipse, we'd love to see your results posted on IceInSpace so please register and post your images to the Solar System section. Upcoming Lunar EclipsesHere's a quick listing of the upcoming Partial and Total Lunar Eclipses visible from Australia and New Zealand over the next 10 years.
Further Reading and ResourcesArticle by Mike Salway (iceman). Discuss this Article on the IceInSpace Forum.  |
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