The Optolong IR Pass 685nm Filter blocks wavelengths below 670nm to enhance contrast and surface detail and reduce the effects of seeing when used in IR-LRGB imaging of the moon and planets. Atmospheric seeing and distortion diminish as you move further away from visible light into the infrared, and since CCD and CMOS sensors are sensitive to IR light, imaging in the infrared will improve your results.
Features precise helical focus adjustment with convenient thumbscrew focus lock
Compact and with a built-in helical focuser for precise focusing of potential guide stars
UNC(1/4-20)-mount equipped for secure threaded attachment of autoguide devices
Ensures that main mirror accurately tracks the celestial body to be observed and matches perfectly with today's sensitive autoguiding cameras for easy guide star acquisition
Need extension tube for extra focal length to use with eyepiece
ZWO has released a brand-new FF65APO 0.75× full frame reducer with a four-element optical design. It has a reduction factor of 0.75x, which gives the FF65APO f/6.4 astrograph a shortened focal ratio of f/4.8 and a shorter focal length of 312mm. This allows for less total integration time and a wider field of view, bringing more convenience and possibilities for your wide-field deep sky imaging. The back focus distance is the standard 55mm. It also comes with two thread adapters of M54 and M48, and a built-in M48x0.75 2” filter thread, which makes the connection work simple and convenient.