GALLIUM LIQUID MIRRORS - BASIC TECHNOLOGY, OPTICAL-SHOP TESTS AND OBSERVATIONS

We have investigated the use of gallium and low-melting-temperature ga llium alloys for liquid mirrors. They have advantageous characteristic s with respect to mercury. Simple knife-edge and Ronchi optical tests indicate that gallium mirrors have optical qualities similar to those of mercury mirrors. We have observed stars with a 1-m diameter liquid- mirror telescope that used a gallium-indium ahoy. The instrument opera ted satisfactorily, within the limitations of a very simple telescope and instrumentation. Arguably, our most interesting finding is that th e high melting temperature of gallium is not an obstacle since our exp eriments show that it is easy to supercool in large volumes and quite stable in the supercooled state. Furthermore, eutectic alloys of galli um have significantly lower melting temperatures than pure gallium and are also easy to supercool and stable in the supercooled state. The r esults of our experiments are encouraging and warrant further, more ri gorous, continuation of this work.