The end of the focuser is the multi-functional four-piece photographic adapters，which can be connected to the end thread of the focuser when using.
The backfocus is the standard 55mm. It also has a built-in M48X0.75 (2 inch) filter thread that allows you to screw on filters conveniently.
The Askar new 3 inch 0.76x full frame reducer,with a triplet design and specifically for the 80PHQ, offers a 0.76x reduction in focal ratio, when used with the 80PHQ F/7.5 astrograph,the focal ratio is 5.7, and the reduced focal length is 456 mm, effectively shortening the exposure time and dramatically increasing your field of view and bringing more convenience and possibilities for your deep-sky astrophotography.
SHARPSTAR OPTICS, 3/F, No.5 building , Science and Technology Center, No.79 Jin-Sui Road, Jia-Xing, Zhe-Jiang,314001 China