We are developing an ultra-lightweight and inexpensive mid-sized telescope on an alt-azimuth mount. Utilizing commercially available truss elements and compact high precision bearings we are able to achieve significant weight and cost savings while maintaining mechanical strength and stability.
The design features a structure integrating the mirror-cell and the altitude bearing's arc-rails coupled to a short-armed fork through R-Guide bearings. The fork sits on a turn-table providing rotation about the azimuth axis. The telescope-tube connects to an extension of the mirror-cell.
The mount can carry a mirror of up to 3m in diameter, yet is only 5m from the bottom of the base to the top ring and weights only 5000kg without the primary mirror. Assembly of the mount was performed by three students in two weeks and within the budget of $80,000.
We measured the altitude bearing's motion accuracy to be 0".07 (rms) at a constant speed of 2".2/s for 15 minutes in both forward and backward motion without any sign of hysteresis, stick-slip, or backlash.