TransFi Terminator is a possibility. It’s a linear tracking hybrid: air bearing for horizontal, pivot for vertical.
VTA is easily adjusted on the fly. Beam horizontality is easily adjusted on the fly - and this is also a small azimuth adjustment. Large azimuth adjustments are a pain, but intuitive; ditto tangentiality, ditto VTF. All adjustments are reasonably stable and repeatable.
Low pressure air means no messy air supply maintenance.
So for a little pain and $1k you can have an instrument which competes with anything that costs less than a new car. IMO. I have two in an ESL based system, running a Koetsu and a Miyajima.
VTA is easily adjusted on the fly. Beam horizontality is easily adjusted on the fly - and this is also a small azimuth adjustment. Large azimuth adjustments are a pain, but intuitive; ditto tangentiality, ditto VTF. All adjustments are reasonably stable and repeatable.
Low pressure air means no messy air supply maintenance.
So for a little pain and $1k you can have an instrument which competes with anything that costs less than a new car. IMO. I have two in an ESL based system, running a Koetsu and a Miyajima.