speculum metal meaning in Hindi

Examples

1. It was difficult to grind the speculum metal to a regular curvature.
2. It had a diameter, focal length speculum metal objective mirror.
3. Glass is also more thermally stable than speculum metal, allowing it to hold its shape better through temperature changes.
4. All of these larger reflectors suffered from the poor reflectivity and fast tarnishing nature of their speculum metal mirrors.
5. Observations by James Keeler helped establish large reflecting telescopes with metal coated-glass mirrors as astronomically useful, as opposed to earlier cast speculum metal mirrors.
6. He started building his own reflecting telescopes and would spend up to 16 hours a day grinding and polishing the speculum metal primary mirrors.
7. "' Speculum metal "'is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface.
8. The material their primary mirror was made of was speculum metal, a substance that only reflected up to 66 percent of the light that hit it and tarnished in months.
9. Bradley and Samuel Molyneux, having been instructed by Hadley in his methods of polishing speculum metal, succeeded in producing large reflecting telescopes of their own, one of which had a focal length of.
10. Prisms provide advantages over mirrors in an era when polished speculum metal mirrors were inferior and both the silvering of a mirror and the production of glass with flat, parallel surfaces was difficult.