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Procuring material/components: You will need the following parts. The decision of what to buy and build is up to you. 1) Glass discs: Two strictly 12mm or more thick and 4.5" diameter circular glass disc of simple plate glass i.e. window glass. Take care bubbles are not there. (Rs.150/- to 200/-) 2) Grit (grinding powder/abrasive) -
of various numbers for grinding glass These you can procure from any shop in your city which is selling articles to spactacle lens makers. It may be difficult to procure in small quantities so you can directly contact any spectacle lens maker to provide you with these quantities. If they are using Aluminium Oxide in MA numbers, you can take these from them. They will tell you the corresponding numbers like #1000 is MA 3, 800 is MA 2.5, and so on.. Normally the spectacle makers use upto MA3 (or #303) after which they use Red Oxide - a red polishing powder (instead of Cerium Oxide). It is slow in polishing and may produce lot of scratches in the Mirror. 3) Telescope Tube - A PVC Pipe of 4 or 6kg pressure, whose outside dia is 140mm and length 1 meter. These will be available where the drainage pipes are sold. (@Rs.50 to 100/- per foot depending on the quality. A middle medium-hard quality will do. It should neither be soft, of thin wall nor brittle. 4) Speculam (Primary Mirror Holder), can
be made easily or purchased (Rs.300/-) Designing of this scope is such that Ramsdens can also be used without much difference in image quality. These you can purchase from the shops selling scientific items, lenses etc. to schools/colleges. Prefer purchasing eps with AR coating as they give better illumination and suppress ghost images. 8) Finder-scope (to locate objects) -
simple-one can be made easily and better-one giving erect image can be
procured (Rs.450/- onwards). |