On the day of Winter Solstice, North Pole tilts away from the Sun and South Pole tilts towards the Sun. The Winter Solstice occurs exactly when the earth’s axial tilt is farthest away from the sun at its maximum of 23° 26′. So the Sun shines at lowest heights in Northern skies and at maximum heights at Southern skies. The sun is directly overhead on the Tropic of Capricorn during the December solstice. It results in the shortest day in the Northern Hemisphere but at the same time it’s the longest day in Southern Hemisphere. So for people in Southern Hemisphere it’s a Summer Solstice.
Winter Solstice indicates winter at its peak. After this, the length of the day starts increasing and it reaches a point where day and night becomes equal in length at Vernal or Spring Equinox. The day continues to grow longer till Summer Solstice, the longest day.
Lunar Eclipse
As the year comes to an end, celestial geometry presents yet another opportunity to humans to see a wonderful phenomenon called total lunar eclipse but its not for us Indians. December 21st eclipse will not be visible in India as for us it will be happening in daytime.
The lunar eclipse of Dec. 21st falls on the same date as the northern winter solstice. Is this rare? It is indeed, according to Geoff Chester of the US Naval Observatory, who inspected a list of eclipses going back 2000 years. “Since Year 1, I can only find one previous instance of an eclipse matching the same calendar date as the solstice, and that is Dec. 21, 1638,” says Chester. “Fortunately we won’t have to wait 372 years for the next one…that will be on Dec. 21, 2094.”
Unlike solar eclipses, which are dangerous to look at without protective measures and last for only a few minutes, lunar eclipses can be seen unaided over a couple hours. No telescopes or binoculars are needed.
Details: SPACE will conduct a public outreach in collaboration with Nehru Planetarium at Jantar Mantar, New Delhi. Students from various schools of Delhi will be attending and taking part in the competitions. Media are welcome to join, but please be advised that sometimes ASI does not allow TV/Video photography.
Timings – The Winter Solstice will take place at 23:38 UT on 21st Dec (5:08 am IST on 22nd Dec). In New Delhi, sunrise on winter solstice day is at 7:09 am and sunset is at 5:29 pm making it a day which is about 10 hours, 20 min in duration.
The Total Lunar Eclipse will occur on December 21, 2010 at 8:17 UTC (middle of the eclipse), i.e. at 13h 47.0m IST.