Monthly Archives: June 2011

What You Don’t Know About Gaddafi

In the Theatre of the Absurd, anything is possible. However, this latest scenario in Libya has taken absurdity to a whole new dimension. A rag-tag bunch of armed, al-Qaeda affiliated tribesmen, being referred to as a ‘pro-democracy movement’ by British State TV (BBC) and other mainstream media outlets, are now being openly armed and trained by the French, British and American governments. This same Coalition of Crusaders, with the support of the Arab League, is fighting alongside the rebels, launching continual bombing raids on targets in Tripoli and beyond, including Muammar Qadhafi’s compound, in a brazen attempt to assassinate the man and re-colonise Libya. Read the rest of this entry

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Eclipse (Lunar in Solar System)

A lunar eclipse happens at a Full Moon, when the Moon’s tilted orbit brings it into the Earth’s shadow, which can then be seen cast onto the Moon. While not as spectacular as a total solar eclipse, a lunar eclipse is much easier to see; and a total lunar eclipse is an amazing and beautiful sight.

A lunar eclipse is very different to a solar eclipse in terms of how the effects we see are created, because of our different point of view: in a solar eclipse, we stand at a particular point within the shadow of the Moon, and experience the effects of the shadow at that point; but in a lunar eclipse, we witness the whole of the Earth’s shadow falling upon the Moon.

For that reason, the types of lunar eclipses don’t correspond exactly to the types of solar eclipses. In addition, the Earth’s shadow is much larger than the Moon’s — because the Earth is larger — so it becomes possible for the whole Moon to be totally eclipsed, as this diagram shows (bear in mind that the scale is exaggerated; the Earth’s shadow doesn’t really cover a huge part of the Moon’s orbit):

The shadow cast by the Earth has two parts:

In the penumbra, the light from the Sun is partly blocked by the Earth, but not completely. An observer standing on the Moon within the Earth’s penumbra would see part of the Sun obscured; that is, they would see a partial solar eclipse. From Earth, when the Moon passes through the penumbra we see it dimming due to the reduced light, although in practice this can be hard to see with the eye.
In the umbra, the light from the Sun is completely blocked by the Earth. Our lunar observer would see a total solar eclipse; we see the Moon darkened, but glowing a dull red from light scattered by the Earth’s atmosphere.

As seen from the Earth, the penumbra and umbra form 2 concentric circles, through which the Moon passes during an eclipse. The type of eclipse seen depends on how close the Moon passes to the center of the shadow, as shown here….

 

From Nasa:

A concise summary of all lunar eclipses from 2011 through 2020 is presented in the table below. The first column gives the Calendar Date of the instant of greatest eclipse[1]. The second column TD of Greatest Eclipse is the Terrestrial Dynamical Time of greatest eclipse. The third column lists the Eclipse Type which is either Total, Partial, or Penumbral.

Eclipses recur over the Saros cycle, a period of approximately 18 years 11 days. Each eclipse belongs to the Saros Series shown in the 4th column. The Umbral Magnitude[2] (column 5) gives the fraction of the Moon’s diameter immersed in Earth’s umbral shadow at the instant of greatest eclipse. The Eclipse Duration[3] gives the length of the partial eclipse. If the eclipse is total then two durations are listed. The first is the interval between the beginning and end of the partial phases. The second value (in bold) is the duration the total phase. Finally, the Geographic Region of Eclipse Visibility[4] provides a brief description of the regions where each eclipse will be seen.

Two fields in the summary table provide links to graphics and additional information for each eclipse. A figure consisting of a diagram and map for each eclipse may be seen by clicking on the Calendar Date. The top diagram shows the Moon’s trajectory with respect to Earth’s penumbral and umbral shadows. The equidistant projection map below illustrates the geographpic region of visibility for each phase of the eclipse. These figures are described in greater detail in the Key to Lunar Eclipse Maps. Each figure is stored as a PDF file of about 110 kilobytes.

All eclipses belonging to a particular Saros Series are listed in a table linked through the Saros number.

The Key to Lunar Eclipse Decade Table contains a more detailed description of each item in the table.

For more data on lunar eclipses during this period, see Catalog of Lunar Eclipses: 2001 to 2100 .

Lunar Eclipses: 2011 – 2020
Calendar Date TD of Greatest Eclipse Eclipse Type Saros Series Umbral Magnitude Eclipse Duration Geographic Region of Eclipse Visibility
2011 Jun 15 20:13:43 Total 130 1.700 03h39m
01h40m
S.America, Europe, Africa, Asia, Aus.
2011 Dec 10 14:32:56 Total 135 1.106 03h32m
00h51m
Europe, e Africa, Asia, Aus., Pacific, N.A.
2012 Jun 04 11:04:20 Partial 140 0.370 02h07m Asia, Aus., Pacific, Americas
2012 Nov 28 14:34:07 Penumbral 145 -0.187 Europe, e Africa, Asia, Aus., Pacific, N.A.
2013 Apr 25 20:08:38 Partial 112 0.015 00h27m Europe, Africa, Asia, Aus.
2013 May 25 04:11:06 Penumbral 150 -0.934 Americas, Africa
2013 Oct 18 23:51:25 Penumbral 117 -0.272 Americas, Europe, Africa, Asia
2014 Apr 15 07:46:48 Total 122 1.291 03h35m
01h18m
Aus., Pacific, Americas
2014 Oct 08 10:55:44 Total 127 1.166 03h20m
00h59m
Asia, Aus., Pacific, Americas
2015 Apr 04 12:01:24 Total 132 1.001 03h29m
00h05m
Asia, Aus., Pacific, Americas
2015 Sep 28 02:48:17 Total 137 1.276 03h20m
01h12m
e Pacific, Americas, Europe, Africa, w Asia
2016 Mar 23 11:48:21 Penumbral 142 -0.312 Asia, Aus., Pacific, w Americas
2016 Sep 16 18:55:27 Penumbral 147 -0.064 Europe, Africa, Asia, Aus., w Pacific
2017 Feb 11 00:45:03 Penumbral 114 -0.035 Americas, Europe, Africa, Asia
2017 Aug 07 18:21:38 Partial 119 0.246 01h55m Europe, Africa, Asia, Aus.
2018 Jan 31 13:31:00 Total 124 1.315 03h23m
01h16m
Asia, Aus., Pacific, w N.America
2018 Jul 27 20:22:54 Total 129 1.609 03h55m
01h43m
S.America, Europe, Africa, Asia, Aus.
2019 Jan 21 05:13:27 Total 134 1.195 03h17m
01h02m
c Pacific, Americas, Europe, Africa
2019 Jul 16 21:31:55 Partial 139 0.653 02h58m S.America, Europe, Africa, Asia, Aus.
2020 Jan 10 19:11:11 Penumbral 144 -0.116 Europe, Africa, Asia, Aus.
2020 Jun 05 19:26:14 Penumbral 111 -0.405 Europe, Africa, Asia, Aus.
2020 Jul 05 04:31:12 Penumbral 149 -0.644 Americas, sw Europe, Africa
2020 Nov 30 09:44:01 Penumbral 116 -0.262 Asia, Aus., Pacific, Americas

Geographic abbreviations (used above): n = north, s = south, e = east, w = west, c = central


[1] Greatest Eclipse is the instant when the distance between the axis of Earth’s umbral shadow and the center of the Moon’s disk reaches a minimum.

[2] Umbral magnitude is the fraction of the Moon’s diameter obscured by Earth’s umbral shadow at the instant of greatest eclipse. For total eclipses, the umbral magnitude is always greater than or equal to 1. For partial eclipses, the umbral magnitude is always greater than 0 and less than 1. For penumbral eclipses, the umbral magnitude is always negative (i.e., less than 0).

[3] Eclipse Duration is the duration of the partial phase of a partial eclipse. For total eclipses two values are given. The first is the period between the beginning and end of the partial phases, while the second value (in bold is the duration of the total phase.

[4] Geographic Region of Eclipse Visibility is the portion of Earth’s surface where some portion of the eclipse can be seen.

 

Solar Eclipses: 2008 – 2015
Calendar Date TD of Greatest Eclipse Eclipse Type Saros Series Eclipse Magnitude Central Duration Geographic Region of Eclipse Visibility
(Link to Global Map) (Link to Animation) (Link to Google Map) (Link to Saros) (Link to Path Table) (Link to RASC Observers Handbook)
2008 Feb 07 03:56:10 Annular 121 0.965 02m12s Antarctica, e Australia, N. Zealand
[Annular: Antarctica]
2008 Aug 01 10:22:12 Total 126 1.039 02m27s ne N. America, Europe, Asia
[Total: n Canada, Greenland, Siberia, Mongolia, China]
2009 Jan 26 07:59:45 Annular 131 0.928 07m54s s Africa, Antarctica, se Asia, Australia
[Annular: s Indian, Sumatra, Borneo]
2009 Jul 22 02:36:25 Total 136 1.080 06m39s e Asia, Pacific Ocean, Hawaii
[Total: India, Nepal, China, c Pacific]
2010 Jan 15 07:07:39 Annular 141 0.919 11m08s Africa, Asia
[Annular: c Africa, India, Myanmar, China]
2010 Jul 11 19:34:38 Total 146 1.058 05m20s s S. America
[Total: s Pacific, Easter Is., Chile, Argentina]
2011 Jan 04 08:51:42 Partial 151 0.858 Europe, Africa, c Asia
2011 Jun 01 21:17:18 Partial 118 0.601 e Asia, n N. America, Iceland
2011 Jul 01 08:39:30 Partial 156 0.097 s Indian Ocean
2011 Nov 25 06:21:24 Partial 123 0.905 s Africa, Antarctica, Tasmania, N.Z.
2012 May 20 23:53:54 Annular 128 0.944 05m46s Asia, Pacific, N. America
[Annular: China, Japan, Pacific, w U.S.]
2012 Nov 13 22:12:55 Total 133 1.050 04m02s Australia, N.Z., s Pacific, s S. America
[Total: n Australia, s Pacific]
2013 May 10 00:26:20 Annular 138 0.954 06m03s Australia, N.Z., c Pacific
[Annular: n Australia, Solomon Is., c Pacific]
2013 Nov 03 12:47:36 Hybrid 143 1.016 01m40s e Americas, s Europe, Africa
[Hybid: Atlantic, c Africa]
2014 Apr 29 06:04:32 Annular 148 0.987 s Indian, Australia, Antarctica
[Annular: Antarctica]
2014 Oct 23 21:45:39 Partial 153 0.811 n Pacific, N. America
2015 Mar 20 09:46:47 Total 120 1.045 02m47s Iceland, Europe, n Africa, n Asia
[Total: n Atlantic, Faeroe Is, Svalbard]
2015 Sep 13 06:55:19 Partial 125 0.788 s Africa, s Indian, Antarctica