Hey astronomy lovers! Welcome to the second installment of Newtonian telescope vocabulary. As with the first chapter of this series, even if you don’t intend to use the instrument, the vocabulary is still essential for pertinent discussions at the Smith’s School of English in Kotoen スミス英会話 甲東園.
The OTA, Optical Tube Assembly consists of three sections, the UTA, Upper Tube Assembly, the dobsonian mount which houses the mirror cell and the altitude-azimuth bearings, and the truss poles which cleverly hold the two parts together at a very strictly calculated distance and position, and this is primarily based on the optical characteristic of the primary objective mirror. The truss poles are also key to easy construction and break-down of the instrument for portability and easy storage.
The UTA holds the secondary mirror, the focuser, the spider and the finder scope. The primary objective and its cell are constructed around the dobsonian mount near the bottom. It is at the UTA where the observer wants to spend most of the time, but it is the size and quality of the primary objective at the bottom that constitutes the true power of the telescope.
Martin Werner Zander
Smith’s School of English in Kotoen 月謝制 Monthly Tuition English Conversation School