An optimized method for making thin primary mirrors for industrial scale telescopes

Abstract

Fabrication of telescope primary mirrors is considered a costly and challenging process due to the optical precessions required in Astronomy. Conventionally, small telescope mirrors have been made from 3-5 cm thick borosilicate glass plates. However, at present, thin primary mirrors (1-2 cm thick) are at a high demand for applications due to their lightweight and cost- effectiveness. Here, preliminary results of the study on an optimized method for making telescope mirrors of 0.2032 m aperture and 1.2192 m focal length, from 12 mm thick thermally-treated soda-lime glass blanks are disclosed. Polarization tests conducted initially had indicated no signs of tension when loaded with a 100 N force. Dial-gauge measurements and Newton interferometer tests unveiled that the blanks retained the flatness after removing the load. Furthermore, the parallelism of the surfaces remained constant.