CELESTRON 9.25 OPTICAL TUBE ASSEMBLY (CGE DOVETAIL)The Celestron C9. 25 is an unusual size with its 9. 25 aperture and 2350 mm focal length, but many consider it to be the Goldilocks of optical tubesnot too big, not too small. This rugged aluminum optical tube is only 22 inches long and weighs just 20 pounds, making it easy to transport and set up. But the views are much more impressive than what youd expect from such a compact instrument. The tube offers a focal ratio of f 10 with the added