| Geometry |
|---|
| Number of detectors | 4 = 2 x 2 |
| Detector size (pixel) | 2040 x 2040 active pixels (2048 x 2048 with reference pixels) |
| Pixel scale @ center of the field (arcsec / pixel) | 0.306 (sampling is 0.15 with microdithering) |
| Camera field of view | 21.5 arcminute |
| Camera rotation | No rotation - Alignment from run to run: ~1 degree |
| Camera orientation | Aligned with North-South/East-West axis |
| Image quality degradation from center to edges | Hardly any perceptible |
| Field distortion | <0.8% in the corners |
| Median seeing at center | 0.65 arcsec (expected, at K) |
| Mosaic cosmetic quality (% of dead pixels) | A few bad corners |
| Gaps between CCDs (arcsec) | 45 |
| Photometry |
|---|
| Magnitude system | AB |
| Broad-band filters | Y, J, H, Ks |
| Average Detector quantum efficiency over filter (%) | Unknown, 75, 75, 85 (preliminary) |
| Zero points (e- / sec) at 1 airmass (AB system) | First measurements: 25.06, 25.87, 26.37, 26.28 (+/-0.1) |
| Airmass term | 0.02, 0.05, 0.03, 0.05 (expected) |
| Color term | To be measured. Expected to be small. |
| Color (Instrumental to UKIRT Mauna Kea system) (UKIRT mag.) | Y-J J-H J-H H-Ks |
| Median sky brightness | 17.4?, 16.7, 15.4, 15.4 (mag AB / arcsec^2) |
| Sky brightness airmass dependency (offset) | Estimates are: 20, 40, 180, 170 (e- / airmass / sec) |
| Point source MagAB SNR=10 Grey 1hr 0.8" Opt ap. | |
| Field galaxy MagAB SNR=10 Grey 1hr 0.8" 2.2"ap. | |
| Conversion from AB to Vega magnitude system | -0.66, -0.96, -1.40, -1.99 |
| Instrumental magnitude equation | m ~ Zp[e-/sec] - 2.5log(Gain[e-/ADU]) - k(airmass - 1)
OR m ~ Zp[ADU/sec] - k(airmass - 1) (Elixir data) |
| Narrow band filters | Low OH- (1.061 & 1.187), CH4 (On & Off), H2 (v=1-0 S(1)), K continuum, Br gamma |
| Camera |
|---|
| Exposure overhead | 10 seconds are charged |
| Read noise | 30 e- |
| Electronic gain (e- / ADU) | 3.8 e-/adu |
| Dark current | Negligible (~0.05 e-/sec) |
| Digital encoding (bit) | 16 |
| Digital range | 65536 |
| Pixel saturation (ADU) | ~35000 |
| Linearity range within 1%,5%,10% (ADU) | about 5000, 20000, 40000 |
| Residual image after saturation | 2 detectors (N-E & S-W) more affected |
| Crosstalk between channels | "Edge" crosstalk: 50 adu amplitude |
| Telescope & instrument EMI noise | Negligible |
| Pixel full well | 120000 electrons |
| Raw fringe amplitude | no obvious fringe seen |
| FITS file |
|---|
| Raw file format | Multi Extension FITS (main header + 4 extensions (1 per detector), each usually containing a cube) |
| Number of amplifiers per detector | 32 |
| Observing |
|---|
| Immunity to bright stars scattered light | Very good |
| Typical exposure time | 20-40 seconds |
| Minimum exposure time | 5 seconds |
| Shutter accuracy | Perfect (electronic shutter) |
| Uniformity of exposure over the mosaic | Perfect |
| Filter exchange time | 15 seconds |
| Small (60 arcsec or less ) dither | 7 seconds |
| Cosmic rays rate (events / detector / minute) | Unknown |
| Observing mode | Exclusively Queued Service Observing (QSO) |
| Data pre-processing | `I'iwi at CFHT: the IDL Interpretor of the WIRCam Images. |
