We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBTI Exozodi Exoplanet Common Hunt ( LEECH ) exoplanet imaging survey .
Our H,K _ { s } , and L ^ { \prime } band observations resolve the system at angular separations < 0 \farcs 09 .
The components exhibit significant orbital motion over a span of \sim 7 months .
We combine our imaging data with archival images , published speckle interferometry measurements , and existing spectroscopic velocity data to solve the full orbital solution and estimate component masses .
The masses of the K2.0 \pm 0.5 primary and K6.5 \pm 0.5 secondary are 0.83 \pm 0.02 M _ { \odot } and 0.64 \pm 0.02 M _ { \odot } , respectively .
We also derive a system distance of d = 25.87 \pm 0.02 pc and revise the Galactic kinematics of NO UMa .
Our revised Galactic kinematics confirm NO UMa as a nuclear member of the \sim 500 Myr old Ursa Major moving group and it is thus a mass and age benchmark .
We compare the masses of the NO UMa binary components to those predicted by five sets of stellar evolution models at the age of the Ursa Major group .
We find excellent agreement between our measured masses and model predictions with little systematic scatter between the models .
NO UMa joins the short list of nearby , bright , late-type binaries having known ages and fully characterized orbits .