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Monday, 13 June 2011


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BAA electronic bulletin
BAA e-bulletin, 2011 June 11

This coming Wednesday evening, on 15 June, there will be a total eclipse of
the Moon. From southern parts of the UK, the Moon will rise totally
eclipsed, and the majority of the second half of the total phase will be
visible, provided observers have a clear, unobstructed south-eastern
horizon. Sadly, from locations further north, with moonrise occurring later
in the evening, most of the total phase will be over before the Moon rises;
those in northern Scotland will miss totality entirely. Indeed, observers
throughout Europe will miss the early stages of the eclipse because they
occur before moonrise.

The Moon first enters the outer, penumbral part of the Earth's shadow at
17:25 UT, and the partial eclipse begins at 18:23 UT.  The eclipse first
becomes total at 19:23 UT, reaches maximum at 20:13 UT, and ends at 21:03
UT.  The partial eclipse ends at 22:02 UT and the penumbral phase at 23:01

You will need to add an hour to all UT times given in this e-bulletin to
obtain BST.

The entire eclipse will be visible from locations in southern, central and
eastern Africa, the Middle East and India. This is the first lunar eclipse
of 2011, and it occurs at the Moon's ascending node in southern Ophiuchus.
As the Moon passes rather deeply through the Earth's umbral shadow on this
occasion, the total phase will last 100 minutes. The last lunar eclipse to
exceed this duration was in June 2000.

Further information on this eclipse may be found at:

>From southern parts of the British Isles, the Moon will rise totally
eclipsed and the later umbral phases will be visible as twilight falls.
>From such locations, the Moon
will be very low in the south-eastern sky, close to the horizon but in a
gradually darkening sky. From London, the Moon rises at the time of greatest
eclipse (20:13 UT), and only from places in the extreme south-eastern parts
of England does the Moon rise before this time.

The table below lists the times of moonrise for various locations in the
British Isles:

         Location                  Moonrise (UT)

Whitstable                    20:07
Brighton                        20:09
London                          20:13
Southampton                20:15
Cambridge                    20:16
Bristol                           20:23
Plymouth                      20:24
Birmingham                  20:26
Swansea                       20:29
York                              20:31
Liverpool                      20:36
Newcastle-on-Tyne      20:40
Dublin                           20:49
Edinburgh                     20:54
Belfast                          20:56
Glasgow                       20:58
Aberdeen                      20:59

>From the UK, the observable part of the umbral phase will last from moonrise
until 22:02 UT. During totality, the Moon will pass slightly to the north of
the centre of the Earth's umbral shadow, so the northern parts of the
totally eclipsed Moon will most likely appear rather brighter than the
southern part. Indeed, the low brightness of the totally eclipsed Moon,
coupled with its low elevation above the horizon, will likely make the Moon
very difficult to discern at, and for a time after, moonrise. The Moon will
be best located using binoculars or a wide-field telescope at this time.  As
the Moon rises higher in the sky it will become easier to see, but even from
locations in south-eastern England there will be, at most, only about 50
minutes between moonrise and the end of the total phase.

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:

The 2011 June 15 total lunar eclipse is the 34th member of Saros 130, a
series of
71 eclipses in the following sequence: 8 penumbral, 20 partial, 14 total, 22
partial, and 7 penumbral lunar eclipses.

There will be a second lunar eclipse in 2011, on 10 December, but on this
occasion the Moon will have already started leaving the umbra before

The BAA Lunar Section will be pleased to receive observations of the lunar
eclipse.  See the Section's webpage at
for more details.

John Mason
BAA Press and Publicity Officer

51 Orchard Way, Barnham, West Sussex PO22 0HX
BAA-ebulletin mailing list
(c) 2011 British Astronomical Association
Good Clear Skies
Colin James Watling
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
More Info:

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