| Geometry |
|---|
| Number of detectors | 36 = 4 x 9 (ears excluded due to vignetting by filters) |
| Detector size (pixel) | 2048 x 4612 |
| Pixel size (um) | 13.5 |
| Pixel scale @ center of the field (arcsec / pixel) | 0.187 |
| Camera field of view | 0.96 deg x 0.94 deg (without ears) |
| 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 | ~0.05 arcsec |
| Median seeing at center (reduced 2003A sample) | g': 0.77 arcsec, i': 0.66 arcsec |
| Mosaic cosmetic quality (% of dead pixels) | 0.2 |
| Small gaps between CCDs (arcsec) | ~13 (70 pixels) |
| Large gaps (2) between CCD rows (arcsec) | ~80 (425 pixels) |
| Photometry |
|---|
| Magnitude system | AB |
| Filters | u*, g', r', i', z' |
| Average CCD quantum efficiency over filter (%) | 63.00, 85.00, 79.00, 55.00, 20.00 |
| Zero points (e- / sec) at 1 airmass (Zp) | 25.77, 26.96, 26.47, 26.24, 25.30 |
| Zero points (ADU / sec) at 1 airmass (Zp) | 25.25, 26.44, 25.95, 25.72, 24.78 (Elixir data) |
| Gain (e- / ADU) | 1.62 (CCD00) |
| Airmass term (k) | 0.350, 0.150, 0.100, 0.040, 0.030 |
| Color term | 0.241, 0.148, 0.000, 0.083, 0.050 |
| Color (Instrumental to SDSS system) (SDSS mag.) | u*-g' g'-r' g'-r' r'-i' g'-z' |
| Dark sky brightness @ zenith - Moon 0% | 22.70, 22.00, 21.30, 20.30, 19.40 (mag / arcsec^2) |
| Grey sky brightness @ zenith - Moon 30% | 21.20, 21.30, 20.80, 20.30, 19.40 (mag / arcsec^2) |
| Bright sky brightness @ zenith - Moon 60% | 19.70, 20.50, 20.40, 20.30, 19.40 (mag / arcsec^2) |
| Dark sky brightness @ zenith - Moon 0% | 0.580, 3.340, 4.170, 8.350, 8.350 (e- / pixel / sec) |
| Grey sky brightness @ zenith - Moon 30% | 2.340, 6.680, 6.260, 8.350, 8.350 (e- / pixel / sec) |
| Bright sky brightness @ zenith - Moon 60% | 9.350, 13.36, 9.390, 8.350, 8.350 (e- / pixel / sec) |
| Sky brightness airmass dependency (offset) | 0.340, 0.340, 2.460, 11.60, 11.90 (e- / airmass / sec) |
| Point source, SNR=10, 60mn, Dark, 0.8" | 25.10, 25.40, 24.80, 24.20, 23.20 (mag AB) |
| Field galaxy, SNR=10, 60mn, Dark, 0.8" | 24.60, 24.90, 24.10, 23.70, 22.70 (mag AB) |
| Transition from AB to Vega magnitude system | -.346, +.092, -.171, -.401, -.554 (mag) |
| 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) |
| Raw fringe amplitude | ~6% in i', ~15% in z' |
| CFH12K narrow band filters (~42x28 arcmin^2 FOV) | Halpha, HalphaOFF, TiO, CN, Hbeta, HbetaOff, OIII |
| Camera |
|---|
| Readout time (including overhead) | ~40 seconds |
| Read noise (e- / pixel) | ~5 |
| Electronic chaing gain (e- / ADU) | 1.67 (0.2 dispersion over the mosaic) |
| CCD operating temperature (deg. C) | -130 |
| Dark current (e- / pixel / minute) | 0.03 |
| Charge transfer efficiency (parallel & serial) | 0.999995 |
| Digital encoding (bit) | 16 |
| Pixel saturation (ADU) | 65536 (~110,000 e-) |
| Linearity range within ~1% (ADU) | All CCDs except 12,17,23,33,28,20,13,22 (1.5-2.2%) |
| Residual image after saturation | None |
| Crosstalk between channels | None |
| Telescope & instrument EMI noise | None (any action can take place during readout) |
| Pixel full well = blooming threshold (e-) | ~150,000 |
| FITS file |
|---|
| Raw file format | Multi Extension FITS (main header + 36 extensions) |
| Mosaic MEF 36 extensions file size (Megabyte) | ~710 |
| Single CCD FITS image size with overscans (pixel) | 2080 x 4644 |
| Number of amplifiers per CCD image | 2 (due to data splicing) |
| Observing |
|---|
| Immunity to bright stars scattered light | Excellent |
| Typical exposure time (second) | 300 |
| Minimum exposure time (second) | 1 |
| Shutter accuracy (second) | 0.003 |
| Uniformity of exposure over the mosaic | 99% for a 1 sec exposure |
| Filter exchange time (second) | 90 |
| Cosmic rays rate (events / CCD / minute) | 150 |
| Observing mode | Exclusively Queued Service Observing (QSO) |
| Data pre-processing | Elixir at CFHT |
