The focus plane tilting adapter is particularly recommended for sun photography in the h-alpha range, when disturbing wavy lines appear in the image (this is more or less a natural interference phenomenon). The adapter can be used to tilt the camera sensor slightly in relation to the optical axis, thus eliminating interference waves.
For deep-sky photography, the device serves the opposite purpose: if for some reason the camera sensor is not perpendicular to the optical axis, this adapter can be used to correct it.
The 6 adjustment screws on the adapter allow you to adjust the focal plane in any direction. On each side there are T2 threads for attaching different devices. For the Mark II version, the screws are recessed caterpillar screws to accommodate larger cameras.