Sri Lankans and many people in the world will have the rare opportunity of observing the longest Total Lunar Eclipse in the 21st century from tonight until the early hours of tomorrow (July 28).
Prof. Chandana Jayaratne, Director of Astronomy and Space Science Unit in University of Colombo, stated that the total duration of the eclipse is 6 hours and 14 minutes.
On this day, the earth will pass between the sun and the moon and therefore the Moon will disappear into the Earth’s darkest shadow, known as the umbra. For one hour and 43 minutes, the moon will disappear from the sky, entirely obscured by the shadow that our planet casts upon it.
Given the moon is currently the furthest away in its orbit, it will take longer to pass through the shadow causing the eclipse to be the longest in 100 years.
“It is also expected to be the longest blood moon witnessed in 100 years. The Moon will be visible in a scarlet red hue for over 1 hour and 43 minutes, which is 40 per cent longer than any other blood moon measured in recent times,” stated Prof. Jayaratne.
A total lunar eclipse is sometimes called a Blood Moon, because of the reddish colour of the Full Moon takes on when fully eclipsed. As the Sun’s rays pass through the earth’s atmosphere, some colors in the light spectrum are filtered out due to scattering.
Red wavelengths are least affected by this effect, so the light reaching the Moon’s surface has a reddish hue, causing the fully eclipsed Moon to take on a red color.
The eclipse begins at 10.44 p.m. Sri Lanka Standard Time on July 27th with the Moon enters into the penumbra – the less dark shadow of the Earth and will end up at 4.58 a.m. on July 28th, 2018.
For the naked eye observers, the eclipse will start to see from 11.54 p.m. with Moon begins to enter in to the penumbra-the dark shadow of the Earth. The total eclipse begins at 1.00 a.m. on 28th morning, the greatest eclipse occurs at 1.51 a.m. , total part of the eclipse ends up at 2.43 a.m. and partial eclipse ends up at 3.49 a.m. on 28th.
Prof. Jayaratne says, “After that the moon will enter into the less dark shadow of the Earth, the penumbra and only the dimming of the Moon light will occur till eclipse ends at 4.58 a.m. with the moon leaving the penumbral part of the eclipse”.
“If we talk about the world, the areas that are at a prime position to see this eclipse in its full glory are eastern Africa, central Asia and the Middle East. Sri Lankan will not have the opportunity see another total lunar eclipse from beginning to the end again till 2025 and school children in particular shall organize night sky astronomical observation camps using this rare celestial event”, added Prof. Jayaratne.
