Instrument
Basic instrument parameters
Prime Focus Instrument (PFI)
| Item | Description |
|---|---|
| Field of view | ∼1.38 deg (hexagonal - diameter of circumscribed circle) |
| Field of view area | ∼1.25 deg2 |
| Input F number to fiber | 2.8 |
| Fiber core diameter 1 | 127 μm (1.1 arcsec at the FoV center, ∼1.0 arcsec at the edge) |
| Positioner pitch | 8 mm (90.4 arcsec at the FoV center, 82.4 arcsec at the edge) |
| Positioner patrol field | 9.5 mm diameter (107.4 arcsec at the FoV center, 97.9 arcsec at the edge) |
| Fiber minimum separation 2 | ∼30 arcsec |
| Fiber configuration time | ∼130 s |
| Number of fibers 3 | Science fibers 2385 (2394), Fiducial fibers 92 (96) |
| Fiber density | ∼2000 deg-2 / ∼0.6 arcmin-2 |
| Number of AG camera 4 | 6 |
| Field of view of AG camera | ∼5.1 arcmin2 per one camera |
| Sensitivity of AG camera | gaia ∼21.7 AB mag for S/N∼5 in 5 second exposure |
- This is a diameter of the sky projected on to the fiber core not directly but through a microlens with a magnification of 1.28. According to the plate scale without microlens, 100μm subtends ∼1.1 arcsec on the sky.
- The minimum separation includes a physical limitation and a margin for collision avoidance.
- Excluding the broken fibers. Number in parentheses is from the design.
- The AG cameras are mounted surrounding the hexagonal shaped array of fiber positioners.
Spectrograph System (SpS)
| Blue | Red (Low res.) | Red (Med res.) | NIR | |
|---|---|---|---|---|
| Spectral coverage | 380 - 650 nm | 630 - 970 nm | 710 - 885 nm | 940 - 1260 nm |
| Dispersion | ∼0.7 Å/pix | ∼0.9 Å/pix | ∼0.4 Å/pix | ∼0.8 Å/pix |
| Spectral resolution | ∼2.1 Å | ∼2.7 Å | ∼1.6 Å | ∼2.4 Å |
| Resolving power | ∼2500 (@500nm) | ∼3000 (@800nm) | ∼5500 (@800nm) | ∼4500 (@1100nm) |
| Spectrograph throughput 4 | ∼49% (@500nm) | ∼52% (@800nm) | ∼48% (@800nm) | ∼39% (@1100nm) |