List of astronomical interferometers at visible and infrared wavelengths
Here is a list of currently existing astronomical optical interferometers, and some parameters describing their performance.
Current performance of ground-based interferometers
Columns 2-5 determine the range of targets that can be observed and the range of science which can be done. Higher limiting magnitude means that the array can observe fainter sources. The limiting magnitude is determined by the atmospheric seeing, the diameters of the telescopes and the light lost in the system. A larger range of baselines means that a wider variety of science can be done and on a wider range of sources.Columns 6-10 indicate the approximate quality and total amount of science data the array is expected to obtain. This is per year, to account for the average number of cloud-free nights on which each array is operated.
| Interferometer and observing mode | Waveband | Limiting magnitude | Minimum baseline | Maximum baseline | Approx. no. visibility measurements per year | Max ratio of no. phase / no. amplitude measurements | Accuracy of amplitude2 measurements | Accuracy of phase measurements | Number of spectral channels | Comments |
| CHARA Array | V, R, I, J, H, K | 8 | 34 | 330 | 7500 | 0.7 | 1% | 10 | 30000 | 30000 in the visible band; maximum baseline 330-m |
| COAST visible | R, I | 7 | 4 | 60 | 2000 | 0.5 | 4% | 10 | 4? | 300 cloudy nights per year, maximum baseline 100-m |
| COAST infrared | J, H | 3 | 4 | 60 | 100 | 0.5 | 20% | 10 | 1 | 300 cloudy nights per year, maximum baseline 100-m |
| GI2T visible | R, I | 5 | 10 | 65 | 2000 | 0 | 10% | - | 400? | CLOSED in 2006 |
| IOTA | J, H, K, L' | 7 | 6 | 30 | 10000 | 0.3 | 2% | 10 | 1? | Integrated optics beam combiner. CLOSED. |
| ISI | N | 0 | 10 | 50 | 5000 | 0.3 | 1% | 1 | 1000 | Maximum baseline 70-m |
| Keck Interferometer | H, K, L, N | 10.3 | 85 | 85 | 1000 | 0 | 4% | 1 | 330 | Nulling Key Science Underway - No imaging on a single baseline instrument; maximum baseline 11-m. CLOSED. |
| Keck Aperture Masking | J, H, K, L | 2 | 0.5 | 9 | 20000 | 0.9 | 20% | 10 | 1 | CLOSED. |
| MIRA 1.2 | R, I | 3 | 30 | 30 | 500 | 0 | 10% | - | 1 | Mid-Infrared |
| Navy Precision Optical Interferometer visible | V, R, I | 5 | 5 | 300 | 50000 | 0.7 | 4% | 10 | 16 | at NOFS; siderstats operational 4 x 1.8m added apertures in FY13. World's largest optical baseline-437m, 6-phased |
| Palomar Testbed Interferometer | J,H,K | 7 | 86 | 110 | 50000 | 0 | 2% | 0.1 | 5,10 | "dual-star" capable , No imaging on a single baseline instrument. CLOSED 2009. |
| SUSI | B, V, R, I | 5 | 5 | 640 | 5000 | 0 | 4% | 10 | 21 | No imaging on a single baseline instrument; Maximum baseline 160m |
| VLTI +UTs AMBER | J, H, K simultaneously | 7 | 46 | 130 | 400 | 0.3 | 1% | 10 | 2000 | Used for a few weeks per year. Longest overall VLTI Baseline 130m |
| VLTI +ATs AMBER | J, H, K simultaneously | 4 | 46 | 130 | 400 | 0.3 | 1% | 10 | 2000 | Longest overall VLTI Baseline 130m |
| VLTI +UTs VINCI | K | 11 | 46 | 130 | 400 | 0 | >1% | - | 1 | Integrated optics beam combiner. Longest overall VLTI Baseline 130m |
| VLTI +ATs VINCI | K | Never checked | 12 | 200 | 400 | 0 | >1% | - | 1 | Longest overall VLTI Baseline 130m. |
| VLTI +UTs MIDI | N | 4.5 | 46 | 130 | 200 | 0 | 10% | - | 250 | Used for a few weeks per year. Longest overall VLTI Baseline 130m. Dismantled Apr 2015 |
| VLTI +ATs MIDI | N | 4.5 | ? | 200 | 200 | 0 | 10% | - | 250 | VLTI inldes World's largest unfilled apertures. Longest overall VLTI Baseline 130m. Dismantled Apr 2015 |