Zero Shadow Day
4.8star
333 reviews
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Rated for 3+
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About this app
Zero Shadow is a phenomenon when the sun is exactly overhead and the shadows of symmetrical and vertical objects vanishes. This happens for locations between the tropics and is caused by the northern and southern motion of the sun during the course of a year. This app helps you find the Zero Shadow Day for any location.
If you are between Tropic of Cancer and Tropic of Capricorn, then on a particular day (one during Uttarayan and other during Dakshinayan) the Sun will pass directly overhead at local noon. At local noon on this day, a vertical pole will cast no shadow. These are called Zero Shadow Days, or ZSD. This app is an aid to the campaign by the Public Outreach and Education Committee of the Astronomical Society of India for celebrating ZSD.
Inputs and Content by
Dr. Niruj Mohan Ramanujam, ASI POEC
Translations by:
Kannada - Dr B.S. Shylaja of Jawaharlal Nehru Planetarium Bengaluru and Mrs. Jyotsna
Telugu - Teja Teppala
Marathi - Dr. Aniket Sule, HBCSE, ASI POEC.
Hindi - Alok Mandavgane
Spanish - Alvaro Jose Cano Mejia from Colombia
Portuguese Brazilian - José Roberto Vasconcelos Costa
If you are between Tropic of Cancer and Tropic of Capricorn, then on a particular day (one during Uttarayan and other during Dakshinayan) the Sun will pass directly overhead at local noon. At local noon on this day, a vertical pole will cast no shadow. These are called Zero Shadow Days, or ZSD. This app is an aid to the campaign by the Public Outreach and Education Committee of the Astronomical Society of India for celebrating ZSD.
Inputs and Content by
Dr. Niruj Mohan Ramanujam, ASI POEC
Translations by:
Kannada - Dr B.S. Shylaja of Jawaharlal Nehru Planetarium Bengaluru and Mrs. Jyotsna
Telugu - Teja Teppala
Marathi - Dr. Aniket Sule, HBCSE, ASI POEC.
Hindi - Alok Mandavgane
Spanish - Alvaro Jose Cano Mejia from Colombia
Portuguese Brazilian - José Roberto Vasconcelos Costa
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Ratings and reviews
4.8
325 reviews
Ramnath Vaidyanathan
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April 24, 2024
filled with facts and multiple sims to keep the user engaged. thanks dev
Sarthak Choudhary
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July 14, 2020
Gets the job done! Simple to use. Teaches important concepts in astronomy. It would be nice if the app author could provide resources as how to calculate the zero shadow day ourself for those who want to learn to do it.
15 people found this review helpful
Alok Mandavgane
July 14, 2020
Hi, thanks. To explain this calculation shortly, you need to find the date for which the declination of the sun is approximately equal to your latitude. So you need to calculate the declination of the sun for any given date.
Remy Osman
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April 28, 2023
Such a fantastic app and thank you to the Astronomical Society of India for releasing it. It has really helped me visualise how the equation of time and analemma affects sunset times here in Singapore. So happy to have found this. Thank you!
2 people found this review helpful
What's new
Fix for zsd info not showing.
Now you can calculate distance between two places by long pressing on other location. The shortest distance from the chosen location will be shown in the zsd info page
Now you can calculate distance between two places by long pressing on other location. The shortest distance from the chosen location will be shown in the zsd info page
