First 16" f5 Dobsonian

Skeleton tube from Beacon Hill Telescopes in February 2003.
New rocker box, groundboard and secondary light baffle.
Sadly, this telescope no longer exists - it was just too heavy and bulky for me. But its memory lives on in its optics and the (cut down) rocker and groundboard.

Focusser, spider and secondary

I like to have a finder on the focusser board, but it does make the tube fairly secondary heavy.

Mirror cell

Collimation is difficult, requiring two spanners to adjust each bolt, but because the tube is solid, the collimation rarely changes.

Altitude bearings

Although the altitude bearings are of small diameter, putting the pads at a wide angle increases the frictional force to the optimum. The pressure must be much higher than the 15 psi recommended for Teflon / Ebony Star, but seems fine for whatever the yellow material is.

Pros:

• The bearings work well
• It holds collimation well
• It's very solid

Cons:

• It's too heavy and bulky for me to move around and set up easily. The complete tube has to be lifted on and off the altitude bearings. Wheels are then fitted so it can be moved in and out of the house. It's awkward to get through the back door. The rocker / groundboard has to be manhandled.
• The cooling of the mirror is slowed down by a thick aluminium plate.
• Collimation is difficult, although it doesn't need to be done often.