11. In amateur astrophotography, a Bahtinov mask can be used to focus small astronomical telescopes accurately. 12. This novel astronomical telescope has been assigned the duty of detecting cosmic neutrinos and their source. 13. Binoculars are widely used by amateur telescope makers, essentially using two refracting or reflecting astronomical telescopes . 14. He also manufactured eighty percent of all astronomical telescopes made in the United States at this time. 15. Astronomical telescopes gather light using curved mirrors.16. It was also on that occasion, that he first had the opportunity to use an astronomical telescope . 17. Henry Lawson offered his collection of astronomical telescopes , but the project failed through lack of government funding. 18. These sights are also used on astronomical telescopes as finderscopes, to help aim the telescope at the desired object. 19. Photon detectors such as CCDs in astronomical telescopes , spectrometers, or very high-end digital cameras are often cooled by Peltier elements. 20. Early in the twenieth century the government funded the construction of one of the largest astronomical telescopes in the world.
