The primary mirror center mark is the core reference point of the dimming axis of the Newtonian reflector telescope, which is convenient for optical calibration of the eyepiece or machine calibration of the eyepiece dimming axis after lens installation.
Please select the main mirror, or secondary mirror, or complete accessories according to your needs
Mirror-related knowledge
The difference between spherical primary mirror and parabolic primary mirror:
Spherical mirrors inherently cannot converge the light from the edges and the center together. Therefore, in cases of large aperture and short focal ratio, it will result in loose imaging, blurred edges, and other issues.
In contrast, parabolic primary mirrors have inherent advantages. They can effectively correct aberrations, so for achieving good observation results, it is recommended to use parabolic mirror type.