TWO CELESTIAL EVENTS ON 21 DECEMBER
(Total Lunar Eclipse – Not Visible In India & Winter Solstice - Shortest Day of the year)
On 21st December 2010 last eclipse of the year which is Total Lunar Eclipse would occur. The eclipse will be visible in the region covering Europe, West Africa, the Americas, the Pacific Ocean, eastern Australia, the Philippines and eastern and northern Asia. Whereas this eclipse is not visible in India.
TIMINGS As Per Indian Standard Time (IST): Broadly speaking the Eclipse begins at 10.58 a.m. IST passing through various phases and ends at 4. 36 p.m. IST.
However the Umbral phase is generally considered as actual eclipse for various ceremonies by general public. i.e. Moon enters the Umbra (dark part of earth shadow ) at 12.02 p.m IST and leaves umbra at 3.32 p.m IST. Importantly Moon enters totality phase at 1.10 p.m noon and ends at 2.24 p.m.
Next Eclipse: The next Eclipse which is Partial Solar Eclipse will occur on 4th January 2011 and would be visible in few northern states of India whereas rest of the country cannot see this eclipse. Importantly the next Lunar Eclipse visible from India would occur on 15 June 2011 which is Total Lunar Eclipse.
Winter Solstice – Shortest Day Longest Night: another event Winter Solstice will occur on 21st Dec, 2010 (11:38p.m UTC) due to which people (in northern hemisphere countries) can experience the day to be short and night to be longest. This occurs because Earth’s axial tilt (on 21 Dec 2010) is farthest away from the sun.
Explanation/Notes :
Brief about Lunar Eclipse: A Lunar Eclipse occurs when earth in course of its orbit around sun, comes between moon and sun such a way that moon his hidden in the shadow cast by earth. This can occur only when the Sun, Earth, and Moon are aligned in a straight line, Hence lunar eclipse occurs only when there is full moon.
Penumbra (pratchaya) and Umbra (chaya) : Earth’s shadow has two parts Penumbra (outer lighter part) and Umbra (darker part). All Lunar Eclipse begin with moon first entering penumbra at one end passing through umbral phase and ending with leaving the penumbra on other end. Generally only the Umbral phase (Beginning & Ending) is commonly considered as actual eclipse by general public to follow various rituals and traditions leaving Penumbra passage of moon.
Earth Tilted on its Axis: The Earth during course of its journey around sun rotates on its axis with a tilt of about 23.4°. This phenomenon is the main cause which regulates seasons on earth. Importantly the hemisphere which currently tilted toward the Sun experiences more hours of sunlight each day and the hemisphere facing away from sun will receive less hours of sunlight.
N.SRI RAGHUNANDAN KUMAR GENERAL SECRETARY PLANETARY SOCIETY OF INDIA
