As you all know that 20th of March is the Spring Equinox day. That means on this day Sun rises exactly in the East and sets Exactly in the West. We will use this opportunity to find something which we all know beforehand, our Latitude and Longitude. But what's the point in finding the values which we already know? You all Vamanites know that here in VAMANA PROJECT and in the S.P.A.C.E. astronomy clubs  we never accept the facts as it is. We always try our hands on these facts check them and then accept these. You all remember very well that how much fun it was to do the radius of Earth experiment. Once again we are doing the same shadow experiment but this time we will find out our own location on Earth!! This is also something that is needed for the Venus transit experiment

So on 20th March, We will gather at Jantar Mantar (those who are in other cities can look for an open place where you have sun through out the day) and carry out the shadow experiment again, but this time together and of course the whole VAMANA team will be there with you!!

Things we need you to get from home:

Drawing Board
Drawing Sheets
Gnomon with base
water bottle
cap

Things which we will supply at Jantar Mantar:

Specially designed sheet for shadow measurements
and of course refreshments

Preparation
1. Paste/ tack white paper on  square board.
2. Paste the sheet given by S.P.A.C.E. on the sheet which you have pasted.
3. Measure length of Gnomon several times. Record the Average length in millimeters. This is the height of the gnomon, H.
4. Place the three legged base centrally on the sheet at the point marked CENTRE on the sheet given to you. Fix the three drawing pins.
5. Mark with pencil the centre of the hole in the middle
6. Assemble the gnomon rod into the central hole
7. Make a plumb line by attaching a the weight to the end of a string
Your shadow stick is now ready for use

Marking the shadow
1. Find a site that is flat and open sky  where the sun is visible between 11a.m and 1 pm (A terrace for instance SE to SW segment)
2. Find a flat surface. Place Gnomon with base on the surface. Adjust the base board so that the gnomon is vertical. Check using a plumb line. This is very important
3. Between 11:30 am and 12:45 pm mark the tip the shadow formed by the gnomon whenever we call the time. Ensure that the stick is vertical through out the observations.
4. Make sure that you put the dot in exactly at the tip of the shadow.
5. When our Volunteers ask you about the colour of the ring in which the shadow is falling, call out the colour.
6. Continue till 12:45 pm as and when we ask you to put the mark.

Students and S.P.A.C.E. people will be marking your readings at a bigger graph. By 12:45 when you finish taking the shadow readings, we will have the shortest shadow length as well as the time at which it occurred. Then we will calculate the Coordinates

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