CNC machined primary mirror mask made of aluminum (EN AW-6061), black matte anodized, suitable for Skywatcher 250PDS/Quattro
The precisely machined mirror mask, for installation on the main mirror, effectively covers the mounting clamps* and the outer area of the main mirror, thus helping to avoid unwanted diffraction phenomena caused by the mounting clamps and a sloping edge of the main mirror.
* The installation is done on the original mounting clamps. These may have to be shortened slightly because they overlap the main mirror very far in the original state and can protrude under the aperture ring! The original metal washers on the mounting clamps can be omitted since the aluminum mirror mask is sufficiently stable.