Rare celestial Mars Occultation Event Visible Only In India on April 17

With the last new moon on April 11, the moon will appear half-lit in the evening sky on April 17 as it follows the sun towards the western horizon. If you observe around 5pm, you will notice a small tiny shining dot very close to the Moon. This is Mars, the red planet. Within a few minutes, the red planet will disappear all of a sudden and appear nowhere in the sky. This is the Lunar occultation of Mars which will be visible for the people of India only. 

The moon moves across the sky each night. Being close to the earth, it covers half a degree width in the sky. On this path, there are rare occasions when the moon passes in front of a star and cause occultation which is like a total solar eclipse when the moon covers the object completely and the object disappears for 1-1/2-hours as the moon makes its way across the sky. We see stars appearing to pass behind the moon, disappearing on one and reappearing on the other. 

All planets in our solar system move around the Sun in almost a disk-like structure. When viewed from earth, these planets, and the sun, all move along a line called the ecliptic. The moon also moves close to this line as its orbital plane is inclined 5 degrees. As the moon moves across the sky, moving eastward with each passing day, the moon will pass above or below a planet and the sun every month, notes Atul Bhat of Poornaprajna Amateur Astronomers Club. 

While the passes next to the Sun are known as new moon days, the passes very close to these planets are called the conjunction of the moon with these planets. Each month Moon passes very close to Mars with only a few degrees of space between the two as viewed from earth. As we see the pair from earth, this space between them varies from place to place. 

During certain lunar conjunctions with mars, depending upon where one observes this from, Moon will appear to pass in front of Mars and cause an eclipse of Mars aka Lunar Occultation of Mars. In the past few months, such occultations have occurred but were visible only from certain parts of Earth. With the previous lunar occultations were visible from Africa and South America respectively, this month’s lunar occultation will be visible from across India.

Visibility Of Mars Occultation In India

In the evening, due to the blue scattering of the sky, the dark part of the moon will appear blue. Around 5pm, one can try and observe mars disappearing behind the moon behind the darker side. Because the darker side appears blue, it appears as though Mars vanishes from the sky around 5.08pm (in Udupi & Dakshina Kannada). As the sun sets, and darkness arrives, around 6:55pm, Mars reappears from the bright side of the moon, completing the occultation. 

Due to the nature of orbits of the Moon, Earth, and Mars around the Sun, these events occur in a seemingly irregular pattern. In countries such as Indonesia, due to time differences, the disappearance of Mars will also be visible in the dark night sky. In India, disappearance may be difficult sight with the naked eye. However, the reappearance of Mars will be clearly visible and is an event not to be missed for it will happen in the near future. 

While many lunar occultations will occur, none of them will be visible in India. Therefore, this event is not to be missed, Atul Bhat says hoping and wishing that everyone witnesses this beautiful eclipse and enjoy the view with clear skies. 

https://paac.ppc.ac.in/astronomy-event/lunar-occultation-of-mars-17-apr-2021/