AstroZap Focusing Cap for ETX 90
When you want help focusing an image during a CCD or DSLR sessions turn the center knob to the "Open" position and reveal a trio of off-axis masks. This position allows the focusing cap to operate like a Bahtinov mask. The Astrozap Focus Cap doesn't stop there. Rotate the knob again to place the cap in the "Closed" position and take dark frames or use it as a dust cap.Made from lightweight aluminum and powder-coated black, this Astrozap Focusing Cap is both strong and aesthetically pleasing. For installation: Three thumbscrews hold the Focusing Cap firmly in place.
The AstroZap Focusing Cap for ETX 90 will fit 90mm-100mm optical tubes.
