Gurudev Observatory

Zenithal Sun: A Zero Shadow Moment: Shadow Vanishing Act

What is a zenithal Sun?

A zenithal sun or Zero shadow moment is defined as the time when the sun is directly above the Earth's surface at noon, which results in the complete disappearance of the shadows of vertical structures such as poles or pyramids. In astronomical language it is moment when altitude of the Sun is perfectly match with latitude of any given place and on that day the shadow of everything has vanishes for 15 to 30 seconds at local noon. We can also call it a shadow vanishing act.

Event for Education

As usual we use the event to teach some basic principles of astronomy and space science to students and the public. In the past we have demonstrated the event at Gurudev Observatory, at SVP Planetarium and one of the biggest school group, BRG Group of schools of Vadodara. Each year we organise the event at different places to teach the phenomena.

We use

Several tables, hollow PVC pipes of 1", 2 " and 4" diameter, glasses, buckets, bangles, boxes, vessels and utensils to show various angles of the event.


As usual local, state and national level media helps to spread words. Friends from both print and the electronic media helps us to spread the phenomena to more than 10 million people within 24 hrs. All the TV channels telecast the news as breaking news while all print media give it the anchor position in their papers.

Press briefing on the Zenithal sun

Students earn

Students earn true wealth in the form of space science knowledge. They learn the about the tilt of Earth, solstice, local noon and the motion of the Sun in a practical way, and not only in the form of theory.

Gallery of pictures


Zero shadow moment:

Zenithal sun: