The objective in a refracting telescope refracts or bends light. Telescopic beam expanders include refracting and reflective telescopes. Examples of some of the largest achromatic refracting telescopes, over diameter. Magnifying glasses, spectacles, contact lenses, microscopes and refracting telescopes are all examples of this manipulation. This was especially true in refracting telescopes, before the invention of achromatic objective lenses. In a refracting astronomical telescope the entrance pupil is identical with the objective. This telescope was the largest refracting telescope at that time. The largest practical lens size in a refracting telescope is around . All refracting telescopes use the same principles. Hipgnosis designed the packaging, which included George Hardie's iconic refracting prism design on the cover. From these experiments Newton concluded that no improvement could be made in the refracting telescope. In some signals, these lenses were cut to include a specific refracting pattern. Brookite is doubly refracting, as are all orthorhombic minerals, and it is biaxial (+).