Visual demonstration of the performance of the diffraction grating. The zeroth order transmission refers to light that goes straight through the grating without undergoing diffraction (which should be ...

THE German original of this work appeared in the autumn of 1890, and was doubtless eagerly welcomed by many who had felt the want of a handbook of spectroscopy which gave a tolerably detailed account ...

Today, astronomers seek to observe the faintest and most distant objects possible. Extremely Large Telescopes (ELTs), with apertures in the order of several dozen meters, are the next generation ...