ZWO Darkening Ring Set for EFW & ASI461MM-P - DR-D90 petzval The finely CNC machined aluminum

The finely CNC machined aluminum body is both tough and sleek

Cassiopeia & Octans are etched into the reticle

and also a 1/10th wavelength flatness mirror surface to preserve the high quality optical images your telescope will provide

Lowest Useful Magnification: 14 x

ZWO Darkening Ring Set for EFW & ASI461MM-P - DR-D90 petzval The finely CNC machined aluminumThe D90 Darkening Ring Set will help solve any possible light leak issue occurring in the gap between the filter wheel and the ASI461MM P. The set includes four (4) rings. Two have an external diameter of 90 mm and two have an external diameter of 106 mm. All four have an inside diameter of 72 mm and are about 0. 2mm thick. The 90 mm rings go between the 68 OAG and the EFW, and the 106 mm gets between the EFW and the ASI461. Here is how you install