6-station, 5-baseline fringe tracking with the new classic data acquisition system at the Navy Precision Optical Interferometer

M. I. Landavazo; A. M. Jorgensen; B. Sun; K. Newman; David Mozurkewich; G. T. van Belle; Donald J. Hutter; H. R. Schmitt; J. T. Armstrong; E. K. Baines; S. R. Restaino

doi:10.1117/12.2057278

24 July 2014 6-station, 5-baseline fringe tracking with the new classic data acquisition system at the Navy Precision Optical Interferometer

M. I. Landavazo, A. M. Jorgensen, B. Sun, K. Newman, David Mozurkewich, G. T. van Belle, Donald J. Hutter, H. R. Schmitt, J. T. Armstrong, E. K. Baines, S. R. Restaino

Author Affiliations +

Proceedings Volume 9146, Optical and Infrared Interferometry IV; 914621 (2014) https://doi.org/10.1117/12.2057278
Event: SPIE Astronomical Telescopes + Instrumentation, 2014, Montréal, Quebec, Canada

Abstract

The Navy Precision Optical Interferometer (NPOI) has a station layout which makes it uniquely suited for imaging. Stellar surface imaging requires a variety of baseline lengths and in particular long baselines with resolution much smaller than the diameter of the target star. Because the fringe signal-to-noise ratio (SNR) is generally low on such long baselines, fringe-tracking cannot be carried out on those baselines directly. Instead, baseline bootstrapping must be employed in which the long baseline is composed of a number of connected shorter baselines. When fringes are tracked on all the shorter baselines fringes are also present on the long baseline. For compact sources, such as stellar disks, the shorter baselines generally have higher SNR and making them short enough that the source is unresolved by them is ideal. Thus, the resolution, or number of pixels across a stellar disk, is roughly equal to the ratio of the length of the long baseline to the length of the short baselines. The more bootstrapped baselines, the better the images produced. If there is also a wide wavelength coverage, wavelength bootstrapping can also be used under some circumstances to increase the resolution further. The NPOI is unique in that it allows 6-station, 5-baseline bootstrapping, the most of any currently operating interferometer. Furthermore, the NPOI Classic beam combiner has wavelength coverage from 450 nm to 850 nm. However, until now, this capability has not been fully exploited. The stellar surface imaging project which was recently funded by the National Science Foundation is exploiting this capability. The New Classic data acquisition system, reported separately, is the hardware which delivers the data to the fringe-tracking algorithm. In this paper we report on the development of the fringe-tracking capability with the New Classic data acquisition system. We discuss the design of the fringe tracking algorithm and present performance results from simulations and on sky observation.

Citation Download Citation

M. I. Landavazo, A. M. Jorgensen, B. Sun, K. Newman, David Mozurkewich, G. T. van Belle, Donald J. Hutter, H. R. Schmitt, J. T. Armstrong, E. K. Baines, and S. R. Restaino "6-station, 5-baseline fringe tracking with the new classic data acquisition system at the Navy Precision Optical Interferometer", Proc. SPIE 9146, Optical and Infrared Interferometry IV, 914621 (24 July 2014); https://doi.org/10.1117/12.2057278

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available