On Mon, Jan 30, 2023 at 12:16 PM, Dale Ghent wrote:

I also use the M54 spacer variety pack from Agena, and they have similar packs for other diameters.

Most of my stuff is from Agena, I worked up from M54 to M68, it's actually harder to find M68 stuff I found (easier still M48). 

One thing I found is if you mix and match vendors the optical length does not always come out right, as they may not thread in as far (or too far).  I also had some cases (notably Moonlite vs Fireball) where the threads did not mate nicely and they were very hard to screw on/off.

Point being it's often best if you stick to one brand of spacers and adapters where practical.  Also always a good idea when you finish a stack of different stuff to actually measure the length and not trust arithmetic. 

But Agena is my first goto.

Linwood