This is simple coelostat model that I built when I was at IUCAA. The location of this picture is the terrace Muktangan Vidyan Shodhika. Most of the setup is clear from the pictures below however, I have described some key points.
Maharudra Mate (who works there) helped me with this setup.
The coelostat is made using two wooden planks (thickness 12mm, size 30 cm x 15 cm). The length of the plank is aligned north-south. The upper plank is lifted up by inserting a wedge between the planks so that the angle between the two planks is equal to the latitude of the place.
Plastic material used here is for 1 inch (32mm) pipe. One elbow (blue in colour) is fixed to the upper plank using double sided nipple (not shown in the picture), one threaded end plug is fixed to the elbow. Into this goes the 1 inch pipe to which the mirror is already fixed. This also is the polar axis of the coelostat.
The second mirror is mounted on another stand. This mirror has three degrees of freedom. It can placed in such a way that the reflected sunlight from the coelostat falls on the mirror. Using this mirror we can now direct the sunlight to a fixed telescope.
This telescope has a 50 mm lens and a 10x Ramsden eyepiece. The telescope is mounted between two PVC sheets. We cut central holes in the sheets so that the telescope pipe can be inserted into the holes. The is now fairly stable placement of the telescope. Of course this could have been any other telescope.
Note: in the picture above the placement of the telescope and coelostat. They are not on the same line. The coelostat axis is polar aligned but the telescope and the screen can be placed where ever we want.
By rotating the the polar axis of the coelostat we can get the sun exactly where we want.
All the material used in this setup is easily available from hardware store or irrigation suppliers. In case of doubt show this pictures to the suppler. If you are getting this setup made from a carpenter then show these pictures. He will have no problem in making one for you.
And feel free to email me if you have any doubts – paranjpye.arvind@gmail.com
DIYA 