Mk II Dobsonian 16" f5 truss tube

Truss tube

The 25mm tubes are all the same length. There are four left-handed and four fight-handed ones. The top fitting is straight out of K&B and seems to be used on 12.5" Obsessions. The bottom fitting is also from K&B, with the clamp and stop screw fixed to the channel, and the whole thing bolted to the mirror box with just one M6 bolt. The whole tube is extremely rigid when assembled. Just as rigid as Mk I.