End cap for 3.5 inch focusers, with collet clamping | Starlight

If your camera or viewfinder is not exactly perpendicular to the focus ring, this can lead to distorted stars on the edge when photographing. This end cap for 3.5-inch cameras with a collet clamp from Starlight Instruments squeezes a ring evenly around the rim of your accessory. This keeps it centered and one screw doesn't pull it out of alignment.

The end cap is located at the end of the 3.5 inch focus tube, the point where you attach the eyepiece, diagonal, or camera. Check that it fits your focus tube, and if not, look elsewhere. Our focusers and parts.

You notice the centering mainly in astrophotography with a heavy astrocamera. Also check that the end cap fits the housing of the accessories you want to use.

If you want to prevent scratches on a screw point in particular, then look for the end cap with clamp ring.