M68 EXTENSION TUBE - 15mm William Optics The PE grade series is

The PE grade series is designed for professional research studies and applications in which precision homogeneity and on-band transmittance values across the substrate surface are required

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

This model works as a tube extension with an optical thickness of 47mm (without the barrel)

William Optics Flat68III

The Prima Luce Lab Losmandy dovetail for 9

M68 EXTENSION TUBE - 15mm William Optics The PE grade series isThis 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