Science Fair Project Encyclopedia
List of astronomical interferometers at visible and infrared wavelengths
Current Performance of Ground-Based Interferometers
Here is a list of currently existing astronomical interferometers, and some parameters describing their performance.
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 (and the most interesting sources are often very faint). 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 (m) | Maximum baseline (m) | 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| (un-projected baseline) | (measurements per night x nights used per year) | Measure of imaging performance 0 = none | (milli-radians) | (max in use simultaneously) | ||||||
| COAST visible | R, I | 6 | 4 | 60 | 2000 | 0.5 | 4% | 10 | 4? | 300 cloudy nights per year |
| COAST infrared | J, H | 3 | 4 | 60 | 100 | 0.5 | 20% | 10 | 1 | 300 cloudy nights per year |
| GI2T visible | R, I | 5 | 65 | 65 | 2000 | 0 | 10% | - | 400? | |
| IOTA | J, H, K | 7 | 6 | 30 | 10000 | 0.3 | 2% | 10 | 1? | |
| ISI | N | 0 | 10 | 50 | 5000 | 0.3 | 1% | 1 | 1000 | |
| Keck Interferometer | K | 10 | 85 | 85 | 1000 | 1 | 4% | 1 | 1 | |
| Keck Aperture Masking | J, H, K, L | 2 | 0.5 | 9 | 20000 | 0.9 | 20% | 10 | 1 | |
| MIRA 1.2 | R, I | 3 | 30 | 30 | 500 | 0 | 10% | - | 1 | |
| NPOI visible | V, R, I | 5 | 5 | 300 | 50000 | 0.7 | 4% | 10 | 16 | |
| PTI | K | 6 | 110 | 110 | 10000 | 1 | 4% | 0.1 | 1 | |
| SUSI | B, V, R, I | 5 | 5 | 640 | 5000 | 0 | 4% | 10 | ? | |
| VLTI near infrared See below for future performance | J, H, K | 12 | 46 | 130 | 400 | 0.3 | 1% | 10 | 4000? | Used for interferometry a few weeks per year |
| VLTI mid infrared | N | 4 | 46 | 130 | 200 | 0 | 10% | - | 250 | Used for interferometry a few weeks per year |
New Interferometers and Improvements to Existing Interferometers
| Interferometer and observing mode | Waveband | Limiting magnitude | Minimum baseline (m) | Maximum baseline (m) | Approx. no. visibility measurements per year | Max ratio of no. phase / no. amplitude measurements | Accuracy of amplitude2 measurements | Accuracy of best phase measurements | Number of spectral channels | Comments |
|---|---|---|---|---|---|---|---|---|---|---|
| (un-projected baseline) | (measurements per night x nights used per year) | Measure of imaging performance 0 = none | (milli-radians) | (max in use simultaneously) | ||||||
| CHARA | J, H, K | 12 | 70 | 400 | 100000 | 0.7 | 1% | 10 | 100? | 2005? |
| LBTI near infrared | J, H, K | >20 | 8 | 22 | 10000000 | 1 | 30% | 100 | 100? | 2006? |
| MRO | R, I, J, H, K | 14 | 7 | 400 | 100000 | 0.6 | 1% | 10 | 1000? | 2008? |
| VLTI near infrared using 4 ATs and PRIMA | J, H, K | 13 | 8 | 200 | 10000 | 1 | 1% | 0.1 | 4000? | Operating every night 2008? |
| VLTI near infrared using 3 UTs and PRIMA | J, H, K | 16 | 46 | 130 | 500 | 1 | 1% | 0.3 | 4000? | 2008? |
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