12 inch Tile Tool Making

Last week I started working on the tile tool for my 12 inch mirror project. I made it using the white cement and hard floor tiles. My 8 inch tile tool was made in the similar manner however I decided to document the 12 inch one through a detailed video for the benefit of other

Printable Ronchi Screens

Using a Ronchi screen is one of the simplest methods to assess the figure of your telescope mirror. Ronchi is a kind of diffraction grating with a series of black and white parallel lines arranged vertically. When you look at your mirror using the Ronchi screen, the bend of lines tells you whether your mirror