  We present a laser system based on a 48 cm long optical glass resonator. The
large size requires a sophisticated thermal control and optimized mounting
design. A self balancing mounting was essential to reliably reach sensitivities
to acceleration of below $\Delta \nu / \nu$ < 2E-10 /g in all directions.
Furthermore, fiber noise cancellations from a common reference point near the
laser diode to the cavity mirror and to additional user points (Sr clock and
frequency comb) are implemented. Through comparison to other cavity-stabilized
lasers and to a strontium lattice clock an instability of below 1E-16 at
averaging times from 1 s to 1000 s is revealed.
