Plans for Unprecedented Imaging of Stellar Surfaces with the NPOI

This team was recently funded by the NSF for a project to modify the Navy Precision Optical Interferometer (NPOI) to be capable of unprecedented imaging of stellar surface features. The fidelity and resolution of the images are expected to exceed previous interferometric images. The project combines several existing advances and infrastructure at NPOI with modest enhancements. For optimal imaging there are several requirements that should be fulfilled. The observatory should be capable of measuring visibilities on a wide range of baseline lengths and orientations, providing complete UV coverage in a short period of time. It should measure visibility amplitudes with good SNR on all baselines as critical imaging information is often contained in low-amplitude visibilities. It should measure the visibility phase on all baselines. The technologies which can achieve this are the NPOI Y-shaped array with (nearly) equal spacing between telescopes and an ability for rapid configuration. Placing 6-telescopes in a row makes it possible to measure visibilities into the 4th lobe of the visibility function, and coherent integration techniques can be used to obtain good SNR on very small visibilities. Coherently integrated visibilities can be used for imaging with standard radio imaging packages such as AIPS. The commissioning of one additional station, the use of new hardware installed, and software enhancements can make this a reality. In this presentation we will give an overview of the project and its current status.