Imaging of Stellar Surfaces with the Navy Precision Optical Interferometer
Abstract
The Navy Precision Optical Interferometer (NPOI) is a unique observatory that is especially well-suited for interferometric imaging. The key features are an array layout that includes equally, or nearly equally-spaced stations, the ability to observe with 6 telescopes simultaneously, the beam-relay system exibility that allows the 6 observed stations to be placed in a chain-configuration, the reconfigurability that allows the telescopes to be moved, and wide wavelength coverage at visible wavelengths. The chain-configuration makes baseline bootstrapping possible, where the fringes are stabilized on very long baselines far below the fringe-tracking signal-to-noise ratio level and thus obtain high-resolution observations. The reconfigurability and exibility makes it possible to obtain complete Fourier (UV) coverage in only a few nights of observations. The wide visible wavelength coverage has several advantages. First, many stars have high-contrast surface features at visible wavelengths. Second, the wide wavelength coverage makes wavelength bootstrapping possible in which fringe-tracking on short baselines at longer wavelengths can be used to phase observations on long baselines at shorter wavelengths in order to further increase the resolution. In this paper we describe the NPOI Stellar Surface Imaging project, funded by the National Science Foundation, and show one important result that is the bootstrapping of a 5-telescope chain, a feat that has not been achieved at any other interferometer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 18, 2015
- Accession Number
- AD1001973
Entities
People
- Anders M. Jorgensen
- D. J. Hutter
- D. Mozurkewich
- E. K. Baines
- G. T. Van Belle
- H. R. Schmitt
- J. Clark
- John Thomas Armstrong
- S. R. Restaino
Organizations
- United States Naval Research Laboratory