Ancient India and Glass
This paper published by INSA is important for us to read and understand. At this point I just found it and wanted to share it with you.
Reference 1 : http://www.new.dli.ernet.in/rawdataupload/upload/insa/INSA_2/20005a5f_229.pdf : This reference gives the sanskrit text, the translation and the drawings of the spectrometer used by Bharadwaja Maharshi.
Reference 2: http://www.infinityfoundation.com/mandala/t_rv/t_rv_agraw_glass_frameset.htm : Ancient Glass and India. Sen, S. N. and Mamta Chaudhary. New Delhi: Indian National Science Academy. 1985. Pp. 201. Rs. 100/-. by D.P. Agrawal and Manikant Shah : As per the review in the link above: The archaeological evidence show beads, bangles etc and the sanskrit texts use the word kaca – for kaanch or glass. There is no mention in this review about lenses or telescopes.