We measured the angular diameters of six stars using the 6-element observing mode of the Navy Precision Optical Interferometer (NPOI) for the first time since the early 2000s. Four of the diameters ranged from 1.2 mas to 1.9 mas, while the two others were much smaller at approximately 0.5 mas to 0.7 mas, which are the two smallest angular diameters measured to date with the NPOI. There is a larger spread in the measurements than data obtained with 3- or 4- or 5-element modes, which can be attributed in part to the flux imbalance due to the combination of more than 2 siderostats in a single spectrograph, and also to cross talk between multiple baselines related to non-linearities in the fast delay line dither strokes. We plan to address this in the future by using the VISION beam combiner.
Cite
@article{arxiv.2506.01720,
title = {Simultaneous Six-way Observations from the Navy Precision Optical Interferometer},
author = {Ellyn K. Baines and Solvay Blomquist and James H. Clark and Jim Gorney and Erin Maier and Jason Sanborn and Henrique R. Schmitt and Jordan M. Stone and Gerard T. van Belle and Kaspar von Braun},
journal= {arXiv preprint arXiv:2506.01720},
year = {2025}
}