Hey there, science lovers! This is the first of a two-part lesson on the parts of a Newtonian telescope. The vocabulary is important for the proper usage of the instrument but follows closely with the understanding of astronomy as well as the telescope itself, so even if you don’t intend to use the instrument, the language is still a must for a handful of interested English conversation students at Smith’s School of English in Kotoen スミス英会話 甲東園.
In this first installment we look at the focuser region and the altitude-azimuth setting circles. To the right of the UTA, the upper tube assembly, there is the Crayford style 2″ focuser with an 11:1 micro dial. Inserted in the focuser is a TeleVue ParaCorr coma corrector, a special lens designed to flatten out the inherent curvature of the objective mirror and thereby improve the overall image quality. A 15% increase in focal length results, and purists worry that the addition of its four lens elements into the light transmission chain decreases the threshold of visibility. Personally, I think the improvement in visual image quality more than offsets any possible disadvantage in using the coma corrector. Parked inside the corrector is a TeleVue Ethos 13mm eyepiece, a lens with a 100-degree field of view and a true wide-field picture window into space.
Situated on the side of the Dobsonian alt-az mount are the altitude and azimuth digital setting circle encoders and the data computer. This setup allows for quick identification of found objects and can greatly assist in the search for faint phenomena in all parts of the universe, Milky Way Galaxy and The Solar System. Located on the ground next to the telescope is the eyepiece case.
Martin Werner Zander
Smith’s School of English in Kotoen 月謝制 Monthly tuition English conversation school