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Optical Long Baseline Interferometry News

LONG BASELINE STELLAR INTERFEROMETERS

Operational Ground-Based Interferometers

CHARA Array - Center for High Angular Resolution Astronomy Array (Mnt Wilson, California; GSU) Towercam. The CHARA Array hosts VEGA (Observatoire de la Cote d'Azur) and FLUOR - Fiber Linked Unit for Optical Recombination (LESIA, Obs. de Paris, France) as well as MIRC (Michigan InfraRed Combiner).
COAST - Cambridge Optical Aperture Synthesis Telescope, OAS (MRAO, UK).
ISI - Infrared Spatial Interferometer (Mount Wilson Obs., California).
Keck Interferometer (Keck Observatory, OTP, Mauna Kea, Hawaii). Mauna Kea Webcams.
MIRA-1.2 - Mitaka IR Array (Optical and Infrared Astronomy Div., NAOJ, Japan). Overview
NPOI - Navy Prototype Optical Interferometer (Lowell Obs., Arizona). Photos.
PTI - Palomar Testbed Interferometer (Caltech, Mount Palomar, California).
SUSI - Sydney University Stellar Interferometer (Narrabri, Australia).
VLTI - the Very Large Telescope Interferometer (European Southern Observatory, Cerro Paranal, Chile) is now operational with VINCI, MIDI, and AMBER. The astrometric interferometer PRIMA is still under development. The second generation VLTI instruments Matisse, VSI, and GRAVITY are under development. Groups contributing to software and instrumentation of the VLT include LAOG, NEVEC, Obs. de Geneve, Obs. di Arcetri, Obs. de la Cote d'Azur, Obs. de Lyon, Obs. de Paris, ONERA, and the Univ. de Nice. Updates of news from ESO are available by email subscription, and through the ESO Messenger.

The following interferometers have ceased operations - the indicated dates are approximately the dates that the interferometers were operational: 20ft (1920-1931), 50ft (1931-1938), Intensity Interferometer (1964-1976), I2T (1974-1987), Mark I (1979), Mark II (1982-1984), 11.4m prototype (1985-1988), SOIR D'ETE (1979-1993), IRMA (1990-1992), Mark III (1986-1993), I2T/CHARON (1993-1996), MIRA-I (1998-1999), the Grand Interféromètre à 2 Télescopes (1985-2006), and IOTA - Infrared-Optical Telescope Array (1993-2006), Photo. IOTA was host to the IONIC integrated optics beam combiner.

A Timeline of Stellar Interferometry from 1955 to 2000 shows the development of these interferometers.

Ground-Based Interferometers and Instruments under Construction

Large Binocular Telescope (Mnt Graham, Arizona). See live webcams of outside and inside rear, front, and right front views of the telescope enclosure. There are two interferometric beam combiners being developed: NIL (10 microns) and LINC (0.6-2.4 microns).
Magdalena Ridge Observatory (MRO) Webcams. An international scientific collaboration between New Mexico Tech (NMT), the University of Cambridge (UK), and an observatory consortium which includes New Mexico State University (NMSU), New Mexico Highlands University (NMHU), the University of Puerto Rico (UPR), and Los Alamos National Laboratory (LANL). The Magdalena Ridge Observatory project is overseen by the Office of Naval Research (ONR).

Ground-Based Interferometry Projects Under Development

OHANA Optical Hawaiian Array for Nanoradian Astronomy. (See also the OHANA Obs. Paris site.)

Balloon Interferometry

FITE Far-Infrared Interferometric Telescope Experiment (Nagoya University, Japan).

Space Interferometry within NASA's Science Mission Directorate

Since 2006 the interferometry missions that NASA had been planning have almost all been slowded down or deferred indefinately, pending input from NASA's advisory boards - notably the ExoPlanet Task Force of the AAAC, and the upcoming 2010 Decadal Survey reviews.

The interferometry mission concepts have been developed as part of the Exoplanet Exploration Program, which is funded as part of NASA's wider efforts in space science. The Origins and Structure and Evolution of the Universe themes ceased to exist in 2005. The Astrophysics Division is part of NASA's Science Mission Directorate. An Organization Chart of SMD is available. Information about recent progress with Space Science missions can often be found through the Letters from meetings of Subcommittees. NASA Research Announcements relevant to the Exoplanet Exploration Program can be found at the Research Opportunities home page. NASA Research Opportunities are solicited through the NSPIRES website. Various NASA Email Updates for the press and media are also available. For those seeking more information about the politics of NASA science NASA Watch is an excellent resource.

NASA has been contemplating two missions using interferometry, SIM and TPF-I, to discover and characterize extrasolar planets. The role of interferometry in this search is explained through JPL's Planet Quest webpage.

Space Interferometry Mission - 10 m baseline fixed structure. A narrow-angle astrometry mission which had been scheduled for launch mid next decade. SIM was in Phase B of mission development when in 2006 it was converted to a technology program.
Terrestrial Planet Finder Interferometer - a formation flying interferometer to search for Earth-like planets around nearby stars. TPF-I was being developed as a possible collaboration with ESA's Darwin mission for launched sometime before 2020. Ongoing work in 2009 includes broadband nulling with the Adaptive Nuller and demonstrations with the Planet Detection Testbed.

NB: The Bahcall Report of 1991 recommended a space-based Astrometric Interferometry Mission (AIM). There were two contenders for this mission, namely OSI (JPL-based proposal) and POINTS (Harvard-Smithsonian proposal). NASA chose OSI, and OSI now goes by the name of the Space Interferometry Mission (SIM). Work on POINTS was discontinued.

The Astronomy and Astrophysics Survey for this decade (2000-2100) is the McKee-Taylor Report, Astronomy and Astrophysics in the New Millenium (link to full text). The report was released to the public May 19, 2000. The new initiatives are prioritized in Table ES.1, and are described in Chapter 1: Recommendations. The survey committee's support of TPF is described in Chapter 3, Section 2.5. The next decadal survey will be put together through the efforts of the Committee on Astronomy and Astrophysics.

Space Interferometry at ESA

The European Space Agency's involvement with with space interferometry would be as part of its Cosmic Vision, a long-range plan which describes possible missions in the period 2015-2025. Information on the missions can be found at the ESA Space Science Homepage and through the ESA Bulletin. Email notification of news from ESA is available by subscription. The ESA websites for their Industry Portal, Invitations to Tender, and General Studies Program list opportunities for related contracts.

Darwin (ESA) - search for extra-solar planets. For launch no earlier than about 2018.
also see the UK Darwin website.

The Darwin mission was proposed in 2007 as a concept for Phase A Study within ESA's Cosmic Vision, which includes missions beyond 2015. It was not chosen for further study, and will no doubt be re-proposed during the next round in 2010. In 2008-2009 ESA is seeking advice for future planet finding missions through its Exoplanet Roadmap Advisory Team which should produce a draft report in April 2009.

Related work in formation flying in Europe is ongoing. The Proba-3 mission will be a formation flying technology demonstrator funded by ESA. Proba-3 is principally a Xeus precursor. The Swedish Space Agency will fly their Prisma mission in early 2009 with a Darwin metrology breadboard. The French space agency (CNES) is studying Simbol-X as a possible X-ray formation flying mission.

GENIE - Nulling interferometry with the VLTI. Nulling at 3.6 and/or 10 microns. Work on GENIE ceased in late 2006.
COROT - transit survey.

Interferometry Projects Being Studied

OVLA - Optical Very Large Array (LISE, Obs. Haute Provence, France).
SI - Stellar Imager (Goddard Space Flight Center, NASA).
Large-Aperture Mirror Array - LAMA
MAXIM a space-based X-Ray Interferometer.
SPECS Submillimeter Probe of the Evolution of Cosmic Structure (Godard Space Flight Center, NASA).
SPIRIT - Space Infrared Inferferometry Telescope (Jet Propulsion Laboratory).
OSIRIS - Astrometric interferometer to be attached to the Space Station in 2003 (Institute of Astronomy, Russia).

The development of DIVA, the Deutsches Interferometer fur Vielkanalphotometrie und Astrometrie, was halted in November 2002 and the mission was cancelled due to financial problems in early 2003 (AIP, Germany).

The University of Puerto Rico Interferometer, Fenton Hill Observatory, New Mexico, ceased development in late 2001.

Interferometry Related Groups and Institutions

Frontiers of Interferometry in Germany (FrInGe), Heidelberg, Germany.
Jean-Marie Mariotti Center (JMMC), Grenoble, France.
US Interferometry Consortium USIC.
NASA Exoplanet Science Center (NExSci) at Caltech, Pasadena, USA.
Nova-ESO VLTI Expertise Center (NEVEC), Leiden, Netherlands.
Antarctic Research, a European Network for Astrophysics (ARENA)

European Interferometry Initiative for Astronomy.
OPTICON EII-JRA4 Integrating interferometry into mainstream astronomy
Actions Spécifique Haute Résolution Angulaire (INSU/CNRS, France).

Interferometry Related Pages

On The Fringe Summer Schools for the VLTI
Astrometry sites listed by the Hubble Space Telescope Astrometry Team.
Studies in Optical Aperture Synthesis and Image Restoration at ONERA.
Interférométrie Solaire through the Service d'Aéronomie du CNRS.
Concordia Station, AASTINO Project, MASS turbulence profiler; Photos; Concordiastro (France, Italy).

Interferometry with single telescopes

MPIfR Optical & Infrared Interferometry Group (Bonn, Germany).
Peter Tuthill's Home Page (University of Sydney, Australia).
John Monnier's Home Page, (University of Michigan, USA).
Chris Haniff's Astronomy Page (University of Cambridge, UK).
Fourth Catalog of Interferometric Measurements of Binary Stars, W.I. Hartkopf, B.D. Mason, G.L. Wycoff, and H.A. McAlister
Le Coronographe Interférentiel Achromatique (Obs. Nice, France).
SPeckle pour Imagerie par Deconvolution (SPID) (Observatoire de Lyon, France).
Fine Guidance Sensor Homepage from the Space Telescope Science Institute.
Ein visuelles Stern-Interferometer im Eigenbau described by Franz Kerschbaum in Sterne und Weltraum.

Please note that some of the links previously contained on this page (links to tutorial material in particular) have been moved to the Introduction page of OLBIN.

Selected Astronomical Resources

Extrasolar Planets Encyclopaedia (Obs. de Paris, France) and US Mirror Site
The Washington Double Star Catalog, B.D. Mason, G.L. Wycoff, and W.I. Hartkopf
CADARS catalog of Apparent Diameters and Absolute Radii of Stars (Pasinetti and Fracassini+ 2001).
Astronomical Applications from USNO Data Services.
Quelques liens sur l'Astronomie.
AstroWeb: Astronomical Internet Resources

Formation Flying Links

Darwin and TPF-I will require formation flying technology to control the relative positions of satellites that are several tens to several hundred meters apart with a resolution of several centimeters or tens of centimeters. The following notes describe missions with related technology.

The term formation flying is also applied to what might be termed constellations where the separation is roughly 100 km or more, and the resolution is only at the kilometer level. Examples of this include missions such as the two satellites that comprise GRACE, and the Earth-observing "A-train" constellation which includes Cloudsat and Calipso. Also the four microsatellites of the Essaim technology demonstrator, although described as a formation, are each several hundred kilometers apart. The four satellites of ESA's Cluster mission are another example, although this constellation has an orbit with a larger eccentricity. Future constellation missions include Swarm, to be launched about 2010.

Closer formation flying in Earth-orbit, with separations of tens of kilometers or even less than 2 km, is being planned for TanDEM-X. TanDEM-X is an Earth-observing synthetic aperture radar designed as an upgrade to the TerraSAR-X mission and having a proposed launch date of 2008.

Autonomous Rendezvous and Docking missions are a separate, but also active area of research. The entirely autonomous NASA DART mission ended prematurely with a mishap in 2004. However, the DARPA Orbital Express mission, although not entirely autonomous, was a tremendous success.

DARPA is currently sponsoring futher work related to Formation Flying, which involves fractionated spacecraft.

The AFRL co-sponsors the University Nanosatellite Program. The winner of the Nanosat-3 competition was the University of Texas at Austin, whose FASTRAC satellites will test aspects of close formation flying.

Darwin/TPF Related Missions and Research

Prisma (Swedish Space Corporation) launch in second half of 2008.
Proba Missions and Proba-3 (ESA) target launch date of 2010

X-Ray Observatories

Simbol-X (CNES) Phase A study for possible launch in 2013
Xeus (ESA) candidate for Cosmic Vision ~2020 launch.

DARPA and AFRL Projects

SPHERES (MIT)

Research Teams, Ground-based Testbeds, and other links

GMV (Spain).
Distributed Space Systems
Tethers (Wikipedia)
School of Aeronautics and Astronautics (Purdue University).
BNSC Workshop 2006
Princeton Satellite Systems
Distributed Spacecraft Technology JPL.
Flight Robotics Laboratory MSFC.

Software Links

Difmap home page - software for synthesis imaging of visibility data (Martin Shepherd, Caltech).
AIPS++, FITS archive, and other NRAO Software Resources.
Hard real-time control with Linux: Linux Device Drivers, realtimelinux.org: Comedi.

Hardware Links

Spectral Dynamics, Siglab digital signal analyzer, Module 20-42
Kistler accelerometers, 8692C.
Photonics Resource Center.
Focal Plane Arrays from Rockwell and Boeing.
Hawaii and Picnic user guides from the Institute of Astronomy (Cambridge, UK).
Information on using NICMOS arrays from Martin Beckett's thesis (Cambridge, 1996).
CCD-World email forum and links.
L3CCDs, from the Lucky Imaging Team.
Fast-steering mirrors from Ball Aerospace.
Le Verre Fluore K-band single-mode fibers.
Optical Fibre Technology Centre (Sydney, Australia).
CorActive Inc.
Tel Aviv U. Applied Physics mid-infrared single-mode fibers.
Advanced Research & Technology in Photonics, single-mode mid-IR silver halide fibers (Berlin, Germany). Also see the ESA/Darwin news item.
Laser Micromachining Solutions (Macquarie University, Sydney, Australia).
Optoelectronics Research Centre (University of Southampton, UK).
Photonic Crystal Fibers at the University of Bath, Blaze Photonics, and Crystal Fibre.
IRCOM (Limoges, France).
IMEP (Grenoble, France), including LEMO and LPCS.
GeeO (Grenoble, France).
Linux Compatible Hardware.

Aerospace Companies

The following companies have ties or interests in the space interferometry projects of NASA or ESA:

Alcatel Alenia Space (France), Alenia Aerospazio (Italy), Ball Aerospace (US), Dutch Space (NL), Lockheed Martin (US), Astrium (France), TNO TPD (The Netherlands), TRW (US).

The sites that I would most recommend for a visit are the A.A. Michelson links, the Mnt Wilson Virtual Tour, the Virtual Radio Interferometer, and the Origins Web Site.

This page is slowly expanding as I find new items of interest. I update the page periodically using search engines such as Google. I have found Pink Mouse software to be very useful for the photos pages. Meetings of the Grantchester Institute have proved useful. I have started using checklinks to run link verification, and I now keep track of errors through an Error Log. Fabien Malbet introduced me to Web Secretary, which is an absolutely marvelous Perl Script for tracking changes to web pages. I'm thinking of adding a Google Maps feature to OLBIN, time permitting of course: See the very cool Test map. I'm also tempted to try my hand with MediaWiki if it might be useful.

If you see errors or oversights on this page, please contact me. Suggestions for changes are always welcome.

Peter Lawson
lawsonhuey.jpl.nasa.gov

Maintained by Peter Lawson
MS 301-451, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109

Webmaster: Peter R. Lawson