M68 EXTENSION TUBE - 15mm William Optics this leaves 77mm of backfocus

this leaves 77mm of backfocus for your camera and accessories when used together with the Celestron EdgeHD

Oxygen-III and Sulphur-II narrow-band filters boost the contrast of emission nebulae and supernova remnants for professional results

An ideal equatorial mount has its right ascension axis pointed directly at the celestial poles

The large rack and pinion 3" focuser can be rotated 360° to perfectly frame the subject and has a reduction gear of 10:1 for precise focusing

M68 EXTENSION TUBE - 15mm William Optics this leaves 77mm of backfocusThis 15mm M68 extension tube features a male M68 x 1 thread on one end and a female M68 x 1 thread on the other. This is a very useful accessory for making up the exact backfocus distance required by correctors. Specifications Connection side A Male M68 x 1 Connection side B Female M68 x 1 Optical length 15 mm SKU AX M68 EXT15