SCIENCE OF ECLIPSE ( LUNAR) AND THE JUNE 15 2011 TOTAL LUNAR ECLIPSE

ABOVE-

THE SIMULATION SHOWING HOW THE TOTAL LUNAR ECLIPSE WILL APPEAR OVER NAGPUR,INDIA

TIMES DISPLAYED ARE LOCAL = GMT + 5.30HRS

ABOVE- PHASES OF MOON

ONLINE LIVE ECLIPSE ( DURING THE EVENT)

The Central Lunar Eclipse will be shown live through WEBCAST -
By Sky Watchers Association of North Bengal(SWAN) Siliguri, West Bengal
http://www.skywatchersindia.com/
or
http://www.livestream.com/swansiliguri
By Eclipse Chaser Athaenium New Delhi
http://www.ustream.tv/user/eclipsechasers
By Astronation.net at http://www.astronation.net/webcam/10022/342/mondfinsternis-juni-2011.html

The decade's first lunar eclipse as well as the first total lunar eclipse of this year & decade shall take place on Wed 15th June 2011

The Moon shall turn Coppery Red as the scattered light due to Rayleigh's effect strikes the moon and gives the glow!

Science of Eclipse-

Like known by all an Eclipse is an obscuring of light from any celestial object as another cellestial object passes in between the source and observer or the light from the source is blocked by an object leading to visible shadow of that object on another.

Lunar Eclipse is annually occurring phenomena.

Orbital Configuration of the Moon

Since Earth-Moon form a Planet-Moon system, both of them rotate about their centre of mass referred as Barycenter. This barycentre is about 4700km from Earth's centre which

is about 3/4th of Earth's Orbit ( Apx 6400km)

( Right- The Earth as centre and the moon revolving about centre of mass shown as PLUS sign)

The orbit of the moon around the Earth is elliptic. Moon's orbit around the earth makes an angle of 5 Degree 14 mins with earth's celestial equator as well as the ecliptic ( App

arent path of Sun in Earth's sky as viewed from earth or the path traced by earth as seen from the sun)

Its like when you consider a clock let the minute hand pointing from 9 to 3 be the so another minute hand pointing from 2-7 is the moon's orbit around the earth but in the real three dimension of space

Thus moon's orbit crosses the ecliptic two times during one orbit referred as nodes( Explained below)

Moon completes a revolution around the Earth in 27.231 days

( IMG COURTESY- ARVIND PARANJPYE)

Nodes of moon's orbit around the Earth-

Nodes are the two positions in the orbit of moon around the earth where the moon's

orbit intersects the ecliptic. Thus for earth's shadow to be casted on moon or moon blocking the solar disc, the moon must be at a common plane or have co-planar orbits.

But it is not necessary that every approximate 15 days when the moon reaches the node ( Descending Node- When the moon is declining from the ecliptic axis MOVING NORTH TO

SOUTH and

Ascending node- When the moon is inclining the ecliptic axis MOVING SOUTH TO NORTH) eclipse will take place as its not necessary that the relative angular separation of sun and moon is 180 Deg ( Case of Lunar Eclipse) when the moon passes from non sun facing side of the earth or 0 Degree ( Case of Solar Eclipse) when moon is in between earth and sun

For any eclipse, Solar or Lunar- New Moon or Full Moon is required respectively. ( Node and Ecliptic)

Why is this??

When there is New Moon, the moon is in between earth and sun ( Not necessary that its always in a liner path) but remains in inclined or declined position depending on its motion.

During full moon, the moon is in opposite direction that is at the non sun facing side of the earth.

Thus as per definitions of solar and lunar eclipse relating to position of Moon with respect to earth the above condition is satisfied.

During every orbit, moon has the same cellestial longitude required for eclipse ( In 29.53 days) but the celestial latitude is not proper and the concept of Ecliptic limit is introduced

Ecliptic Limit-

It is that minimum angle between the position of moon and the node of the moon's orbit required for an eclipse to occur

Its of two type-

Major Ecliptic Limit

A Lunar Eclipse MAY occur when the moon is at

11° 38' ( Celestial Latitude) of a Node, and a Solar Eclipse MAY occur if there is a New Moon within 17° 25' of a Node.

For a Solar Eclipse to occur, the Moon's Celestial Latitude cannot exceed 1° 27', and must be less than 58' for the Solar Eclipse to be Total or Annular.

• Major Ecliptic Orbit A Lunar Eclipse MUST occur if there is a Full Moon within 9° 39' (Celestial Longitude), of a Node, and a Solar Eclipse MUST occur if there is a New Moon within 15° 23' of a Node.

• If a New or Full Moon occurs within 5° of a Node, the Eclipse will be Total or Annular.

Additionally:

• For a Lunar Eclipse to occur, the Moon's Celestial Latitude at Full Moon cannot exceed about 55', and for that Lunar Eclipse to be Total, Celestial Latitude cannot exceed 26'

*** Also

THE MOST IMPORTANT OF ALL - FOR ECLIPSE A PERFECT LINEAR ALIGNMENT,THE SUN-MOON-EARTH NEEDS TO BE PERFECTLY ALIGNED AND THIS CAN HAPPEN ONLY WHEN THE MOON IS AT ONE OF THE NODES AND THE SUN ALSO AT ONE OF THE NODES OR WITHIN THE ECLIPTIC LIMIT

***

An Interesting animation here

Thus for any eclipse to happen,above condition mentioned be satisfied.

June 15 2011 Total Lunar Eclipse-

The June 15 2011 Lunar Eclipse shall be the first lunar eclipse of the year and THE FIRST ECLIPSE SINCE 2000 WHERE THE MOON WILL PASS THROUGH THE CENTRAL PORTION OF EARTH'S SHADOW ( UMBRA)

THE PREVIOUS LUNAR ECLIPSES ( NOT OF THE 2000 LUNAR ECLIPSE),MOON PASSED NOT THROUGH EXACT CENTRAL UMBRA BUT SLIGHTLY ABOVE CENTRAL UMBRAL REGION.

THE ECLIPSE BEGINS WITH THE FIRST CONTACT ( P1)

AT 17:23:05 UT ON WED,15TH JUNE 2011

Visibility-

Europe, Africa, Asia, Australia, New Zealand, southern South America and eastern South America. Places that won’t see the eclipse at all include Hawaii, North America, northwestern South America, Greenland, Iceland and the Arctic.

WITH THE SUN SETTING OVER EUROPE, THE CONTINENT SHALL WITNESS THE ECLIPSE AFTER SUN SETS TILL AROUND MID NIGHT.

EUROPE SHALL SEE A UMBRAL ECLIPSE MISSING THE INITIAL STAGES OF ECLIPSE AS THE MOON WILL BE BELOW THE HORIZON. THUS THE MOON WILL RISE IN ECLIPSE ONLY IN EUROPE

*** TOTALITY SHALL NOT BE SEEN BY NORTHERN SCOTLAND,SCANDINAVIA***

EAST ASIA,EAST AUSTRALIA AND NEW ZEALAND WILL MISS LAST PHASES OF ECLIPSE AS THE MOON SETS IN ECLIPSE ONLY

TIMINGS- ( UTC)

P1 - 17:23:05

U1- 18:22:37

U2- 19:22:11

GREATEST- 20:12:37

U3 - 21:03:22

U4 - 22:02:35

P4 - 23:02:15

TIMING IN INDIAN STANDARD TIME ( IST= GMT+5.30HRS)

2011	stage	Phase	time (IST)
Jun 15	1	Moon enters penumbra	22:52:52
Jun 15	2	Moon enters umbra	23:52:24
Jun 16	3	Start of totality	00:51:57
Jun 16	4	Maximum eclipse	01:42:24
Jun 16	5	End of totality	02:32:50
Jun 16	6	Moon leaves umbra	03:32:22
Jun 16	7	Moon leaves penumbra	04:32:02

CHARACTERISTICS-

*** DARKEST ECLIPSE SINCE JULY 16 2000 LUNAR ECLIPSE AS THIS TIME MOON'S CENTRE PASSES THROUGH 5.3 ARCMINUTES OF SHADOW AXIS***

*** NEXT DARKER ECLIPSE ON JULY 27 2018***

*** EARTH'S SHADOW FALLS IN CONSTELLATION OPHIUCHUS NORTH OF SCORPIUS***

B9.5Ve spectral class star BSC 51 OPH TO LIE IN THE UMBRA OF THE EARTH'S SHADOW

RIGHT-

THE MOON AS THE CENTRAL COPPERY RED OBJECT SURROUNDED BY EARTH'S SHADOW AND BSC 51 OPH TO ITS LOWER RIGHT AS TO BE SEEN FROM NAGPUR,INDIA DURING PEAK ECLIPSE

SAROS- 130

GAMMA- 0.090

PENUMBRA ( MAGNITUDE) - 2.712

UMBRA ( MAGNITUDE) 1.705

TOTALITY- 100 MINS AND 52 SECONDS

FOR INDIA-

ECLIPSE DURATION - 22:52 ( 15TH JUNE) TO 0432 ( 16TH JUNE) IST

MAXIMUM ECLIPSE AT 0142( 16TH JUNE) IST

REFERENCES AND COURTESY-

1] ARVIND PARANJPYE FOR TABULAR FORM AND IMAGE

http://www.iucaa.ernet.in/~scipop/Eclipses/Luna15jun11/lunar_eclipse_1106.htm

2] WIKIPEDIA

3] ECLIPSE @ NASA

4] CARTES DU CIEL SOFTWARE