ZWO 2" SII 7nm Narrowband Filter - SII7NMD2 16.5 mm Eyepieces holding it securely with a

holding it securely with a setscrew to a standard size 1

The adapter offers an ultra-secure threaded connection to your telescope

The collimation eyepiece is more accurate than the simple Collimation Tool

Visual Back Adapter for 2"

and perfect star shapes

ZWO 2" SII 7nm Narrowband Filter - SII7NMD2 16.5 mm Eyepieces holding it securely with aThe ZWO SII 7nm Narrowband Filter passes light at the 672nm wavelength with a bandpass of 7nm for nebula observation. It is suitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants. Use this SII (Sulfur II) with H alpha and Oxygen III narrowband filters (SHO Set) for tricolor CCD astrophotography. This rendition of the ZWO SII 7nm Filter is housed in a 2" threaded metal cell and can be used in 2" filter wheels