A good number of people were successful in witnessing the final phases of the total lunar eclipse from the UK. Here are a few taken by members of the BAA.
This Saturday afternoon, on 10 December, there will be a total eclipse of the Moon. Eclipses of the Moon occur when the Full Moon passes through the cone of shadow cast by the Earth into space. The eclipse first becomes total at 14:06 UT, reaches maximum at 14:32 UT, and ends at 14:57 UT. The partial eclipse ends at 16:18 UT.
Eclipsed Moon on 21st February 2008 by Ian Halsey
Unfortunately, from the UK, the Moon will already have started leaving the umbra (the central, dark part of the Moon’s shadow) well before moonrise, and the observable part of the partial phase will last from moonrise until 16:18 UT.
From London, Moonrise is at 15:51 UT, from Norwich it is at 15:39 UT and from Sheffield at 15:46 UT. Accordingly observers in Eastern parts of the UK will be able to see just the last 30-40 minutes of the partial phase, provided they have a clear, unobstructed north-eastern horizon.
Sadly, from locations further north and west, with moonrise occurring later in the afternoon, most of the partial phase will be over before the Moon rises. Observers should go out at about the time of local Moonrise when, if the sky is clear, the partially-eclipsed Moon may be glimpsed very low down, close to the horizon, in the north-eastern sky.
One never quite knows how dark or how bright a lunar eclipse will be. Everything depends on the conditions in the Earth’s upper atmosphere through which all light falling onto the shadowed Moon has to pass. There have been eclipses when the Moon has been difficult to find even with a telescope, while at other eclipses it has remained bright red or vividly coloured.
This total lunar eclipse takes place at the Moon’s descending node in eastern Taurus, four days after apogee. The Moon’s orbital trajectory takes it through the southern half of Earth’s umbral shadow. Although the eclipse is not central, the total phase still lasts 51 minutes. Eastern Asia, Indonesia, Australia and Japan are best placed for viewing this eclipse, near midnight and with the Moon at a good altitude above the horizon.
Further information on this eclipse may be found at:
http://eclipse.gsfc.nasa.gov/OH/OH2011.html#LE2011Dec10T
At the moment it seems likely that clouds will disappoint many trying to view tonights total eclipse of the Moon from the UK.
However, BAA Member Naimul Islam Opu in Dhaka, Bangladesh is planning to Live Broadcast the eclipse. You will be able to view it at:
Early this Tuesday morning, on 21 December, the day of the winter solstice, there will be a total eclipse of the Moon. The Moon first enters the outer, penumbral part of the Earth’s shadow at 05:29 UT, and the partial eclipse begins at 06:32 UT. The eclipse first becomes total at 07:40 UT, reaches maximum at 08:17 UT, and ends at 08:53 UT.
The entire eclipse will be visible after local midnight from Canada, the USA, central America and the north-western tip of South America. The eclipse occurs at the Moon’s descending node in eastern Taurus, four days before perigee. The Moon will be full at 08:13 UT. Further information on this eclipse may be found at:
http://eclipse.gsfc.nasa.gov/OH/OH2010.html#LE2010Dec21T
From southern parts of the British Isles, the initial umbral phases will be visible, but the Moon will be dropping down into the western sky as dawn approaches. From such locations, when totality begins at 07:40 UT, the Moon will be very low in the west-north-western sky, close to the horizon and in a rapidly brightening sky. From locations in Scotland and Northern Ireland, totality will be visible in its entirety, but the Moon will be low down after the time of greatest eclipse (08:17 UT).
From London, sunrise is at 08:04 UT with moonset just seven minutes later.
The table below lists the times of moonset for various locations in the British Isles:
Location Moonset (UT)
Brighton 08:08
London 08:11
Bristol 08:21
Birmingham 08:25
Swansea 08:28
York 08:30
Liverpool 08:35
Newcastle-upon-Tyne 08:39
Dublin 08:48
Belfast 08:55
Glasgow 08:57
Aberdeen 08:58
The umbral phase lasts from 06:32 UT until 10:01 UT. During totality, the Moon tracks through the northern part of the Earth’s umbral shadow, so for those observers watching it high up in a clear sky, the southern half of the totally eclipsed Moon will most likely appear considerably darker than the northern part.
One never quite knows how dark or how bright a lunar eclipse will be. Everything depends on the conditions in the Earth’s upper atmosphere through which all light falling onto the shadowed Moon has to pass. There have been eclipses when the Moon has been difficult to find even with a telescope, while at other eclipses it has remained bright red or vividly coloured.
For observers in the British Isles, the very low elevation of the Moon during the total phase means that it is not possible to predict the exact brightness distribution in the umbra, so observers are encouraged to estimate the brightness using the Danjon scale at different times during totality. Note that it may also be necessary to assign different Danjon values to different portions of the Moon (i.e., north vs. south).
For an explanation of the Danjon scale of lunar eclipse brightness visit:
http://eclipse.gsfc.nasa.gov/OH/OHres/Danjon.html
The 2010 December 21 total lunar eclipse belongs to Saros 125, a series of 72 eclipses in the following sequence: 17 penumbral, 13 partial, 26 total, 9 partial, and 7 penumbral lunar eclipses.
There will be two total lunar eclipses in 2011, on 15 June and 10 December, but neither will be visible in its entirety from the British Isles.
The BAA Lunar Section will be pleased to receive observations of the lunar eclipse. See the Section’s webpage at http://www.baalunarsection.org.uk/ for more details.
John Mason
BAA Press and Publicity Officer
@britastro