A fortnight after the partial solar eclipse on October 25, there is going to be another eclipse on Tuesday, November 8.
A total lunar eclipse, when the full moon will pass through the shadow region of the earth and for some time will be eclipsed.
The concluding part of the eclipse will be visible in India, Pakistan, adjoining countries and parts of Russia.
A lunar eclipse occurs during a full moon night because of the alignment of the sun, earth and moon almost on the same plane in a straight line. During this alignment, the moon passes through the shadow region of the earth for some time.
We experience full moon when the earth appears between the sun and the moon and the face of the moon, as seen from the earth, gets fully illuminated by the sun. But in situations when these three bodies exactly come into a straight configuration, the moon gets darkened for some period as it passes through the shadow of the earth and we call it a lunar eclipse.
On November 8, it will be a night of a total lunar eclipse, when the moon in its entirety will pass through the shadow cast by the earth, blocking the sunlight from falling onto the lunar surface.
A lunar eclipse passes through different phases, as it moves through the shadow. The relative size and distance of the earth and sun is such that the sunlight falling onto the earth creates a complete, dark shadow zone which is called the “umbra”, but around the umbra there is a partially lit, incomplete shadow region called “penumbra”.
During the progression of a lunar eclipse, the moon first enters the penumbra and technically starts getting eclipsed, but the “penumbral eclipse” is not always discernible to the naked eye. It is only when the moon enters the umbral region of the earth’s shadow that we see the moon getting partially eclipsed. If the entire Moon passes through this umbral region or the complete shadow, one experiences a total lunar eclipse, which, with the passage of time will leave its total eclipse phase and will again be partially eclipsed before coming out of umbral shadow first and then the penumbral shadow.
On November 8, the partial eclipse of the moon will begin at around 14:39 IST. The eclipse will reach its totality phase around 15:46 hrs. The eclipse in terms of the darkness of the moon will be maximum, at 16:29 hrs, when the moon will be deep inside the shadow of the earth. The total eclipse will end at around 17:11 hrs and ultimately the partial eclipse will end around 18:19 hrs.
Quite often an fully eclipsed moon is referred to as a “bloodmoon”, where the reddish colour of a totally eclipsed moon is caused by earth completely blocking direct sunlight from reaching the moon, with the only light reflected from the lunar surface has been refracted by earth’s atmosphere. This light appears reddish since the red part of the white light coming from the sun and passing through the earth’s atmosphere are scattered much less that the blue part of the sunlight. The same phenomena is observed during almost every sunrise or sunset. The darkness of the eclipsed moon in addition to this red colour makes it look blood red in appearance.
On November 8, the moon rise over India will occur between 16:30 and 18:10 hrs, at different times for different geographical locations. The eclipse will be visible from all parts of India from the moonrise time, but the beginning phase both the partial and total eclipse will not be visible because both the event begins when moon is below the horizon everywhere in India.
Some parts of eastern India, including Kolkata, will experience the total phase of the lunar eclipse, whereas in rest of the country will only be able to see the progression of the partial phase of the eclipse, which will end at around 18:19 hrs.
In Kolkata, on November 8, the moon will start rising from the eastern horizon at around 16:52 hrs. and will be completely visible by 16:54 hrs. So, till 17:11 hrs, sky-lovers and eclipse enthusiasts will have the opportunity to see the total lunar eclipse. Afterwards, moon will enter the partial eclipse phase and will become more illuminated as time progresses.
Cities at eastern parts of the country like Kohima, Agartala and Guwahati will observe the total eclipse earlier than Kolkata because of their position. Only in Kohima, the eclipse at its maximum phase can be observed at around 16:29 hrs, when the moon will cross the darkest part of the earth’s shadow.
New Delhi will experience a partial eclipse from moonrise at around 17:31 with 66 per cent obscuration of the moon since the total phase of the eclipse has already ended by then at 17:11 hrs. In Bengaluru, the moon will completely rise on November 8 at 17:57 (actually the moonrise is at 17:49 but the moon will become completely visible a little later) with 23 per cent of its disc obscured by the earth’ shadow, whereas, Mumbai will observe the eclipse at moonrise around 18:03 hrs. with only 14 per cent obscuration.
Since we all enjoy looking at the full moon directly, at least for short period of time, no precautions as in the case of a solar eclipse have to be taken. No special instruments are needed either. But enthusiasts can also use a binocular or a small telescope to get a better view.
Though the next total lunar eclipse will be on March 14, 2025, it will not be seen from India. The next total lunar eclipse that can be seen from India will occur on September 7, 2025, although on October 2023, a minor partial eclipse will be observed from the country. If possible this celestial special event should be observed to once again remind us of our cosmic neighbourhood and the natural phenomenon of eclipse of the closest celestial object to earth.
Dr Debiprosad Duari is director, Institute of Astronomy Space and Earth Science, Kolkata