Pune: “Nearly half of the world will get an opportunity to watch the longest Lunar Eclipse for 130 minutes,” said Arvind Paranjpye, Director of Nehru Planetarium, Nehru Centre, Mumbai. People living in large parts of Australia, Asia, Africa, Europe and South America will get an opportunity to observe the entire eclipse.
This will be one the longest lunar eclipses, lasting for about 103 minutes, as the centres of the sun, earth and moon would nearly be in one straight line. Other than the near-perfect alignment of these solar system bodies, atmosphere plays its role too to make the eclipsed moon really very dark,” he said.
The total lunar eclipse on the night of December 9, 1992 was such a dark lunar eclipse that close to the mid-eclipse, the sky was completely dark. And people could see faint stars too and the moon itself was difficult to spot,” he said.
The eclipse geometry
A lunar eclipse takes place when the moon enters the shadow of the earth. On the night, the earth is directly between the moon and the sun, blocking the sunlight reaching the moon or casting its shadow on the moon. The event obviously takes place on the full moon night. On this night, the moon and the sun are on opposite sides of the earth.
What would happen on the night of July 27, 2018?
The moon will in the penumbral shadow of the earth at about 10:53 pm. Nothing much will be noticeable to the untrained eyes for the next 30 to 40 minutes. After that, one might notice a gradual change in the brightness on the lunar disk.
By 11:54 pm, the moon will be in the umbra of the earth’s shadow and the dark shadow will progress on the lunar disk covering crater by crater of the moon and this will be quite noticeable to the naked eyes. In the next one hour, the moon will be completely inside the shadow of the earth. At this time, the colour of the lunar disk will be red with its many hues - crimson, brick red, etc.
The time of the maximum eclipse is 1:51:27 am on July 28 and at this time, the moon is likely to be ‘out of sight’. But soon its colour will start coming back.
How many eclipses in a year?
It can be calculated that a maximum number of eclipses possible in a year is 7, of which 4 are solar and 3 lunar or 5 solar and 2 lunars. The least possible eclipses during a year are 2, and these are both solar eclipses.