Primary mirror of D203F1000, with an aperture of 203mm and a focal length of 1000mm, is a parabolic reflecting telescope primary mirror. It has an accuracy of 1/6pv and a thickness of approximately 18mm. The thickness may vary slightly due to different manufacturer batches, The surface is coated with an aluminum film and a protective film, and there is a 50mm minor axis (minor edge diameter) secondary mirror. A primary mirror center mark is attached, which is very convenient for adjusting the optical axis with an optical collimating eyepiece or a laser collimating eyepiece after installation. It is a good choice for DIY homemade Newtonian reflecting parabolic telescopes.