The phenomenon of the last day without shadow in 2020, a sign that Indonesia is starting to try Page all

KOMPAS.com– Starting today, Monday (7/9/2020), the Indonesian region will experience a day without shadow or culmination.

A day without shadow, culmination, transit or istiwa ‘is a phenomenon in which the Sun is exactly in the highest position in the sky.

This period, the day without shade will occur gradually in various regions until October 2020.

Indonesian amateur astronomer Marufin Sudibyo said that a day without the sun’s shadow occurs when the sun’s height is exactly 90 degrees, so the sun is right at the zenith point, which is the highest point that can be reached by the circulation of the celestial bodies.

Also read: Days without shade in 34 provinces of Indonesia, write down the date

Astronomically, a day without shadow from the Sun occurs when the value of the Sun’s declination, which is one of the parameters in the celestial coordinate system, is exactly the same and is equal to the latitude of a place.

Marufin said that this phenomenon is also related to the state of the Sun that passes through the latitudes of Indonesia, which is an event in which the declination of the Sun is equal to the latitudes that pass through Indonesia.

“So when the Sun sits directly overhead (occupies the zenith point), the shadows due to sunlight somewhere will disappear for a moment,” Marufin said, on Wednesday (2/9/2020).

Shadow illustration

With a position between 6 degrees north latitude (LU) and 11 degrees south latitude (LS), the Sun will begin to cross latitudes of Indonesia from September 7, 2020 in a southerly direction following its annual rhythm of pseudo-motion.

“After September 7, the Sun will continue to move south until it leaves Indonesia on October 22,” he said.

Last chance and sign of transition

Marufin explained that the phenomenon of the Sun crossing Indonesia at this time was the second and last chance throughout 2020.

Also read: From today until October, Indonesia will live a day without shade

The crossing of the sun is also a sign that Indonesia is beginning to enter the transition, the transition between the dry and rainy seasons.

After the Sun’s crossing, the anthropic convergence zone (ITCZ) will also start moving through Indonesia to the south.

“So (during Shadowless Day) the potential for short duration strong winds will increase,” he said.