MegaPrime/MegaCam - General Specifications & Performance
Starting with semester 2015A, Megacam "ears", consisting of four additional CCDs on the side of the focal plane, are being used, to take advantage of the larger, new set of broad and narrow band filters acquired late 2014.
The old broad band filters are now renamed with a trailing S: uS,gS,rS,iS,zS, while the new broad band filters are simply named u,g,r,i,z.
The reference photometric magnitudes are the AB magnitude in the old (S) filters (SNLS magnitudes).

The old CFH12K narrow band filters are not offered anymore.
Sky background values and airmass terms for the new filters will be updated as statistics become available.
Geometry
Number of detectors 40 (ears included with new filters, vignetted by old (S) 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) gS: 0.77 arcsec, iS: 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 uS, gS, rS, iS, zS, u, g, r, i, z
Average CCD quantum efficiency over filter (%) 63.00, 85.00, 79.00, 55.00, 20.00, 62.00, 83.00, 77.00, 59.00, 19.00
Zero points (e- / sec) at 1 airmass (Zp) 25.74, 27.00, 26.50, 26.38, 25.34, 25.78, 27.11, 26.74, 26.22, 25.02
Zero points (ADU / sec) at 1 airmass (Zp) 25.22, 26.48, 25.98, 25.86, 24.82, 25.26, 26.59, 26.22, 25.70, 24.50 (Elixir data)
Gain (e- / ADU) 1.62 (CCD00)
Airmass term (k) 0.350, 0.150, 0.100, 0.040, 0.030, 0.350, 0.150, 0.100, 0.040, 0.030
Color term (SNLS mags) 0.000, 0.000, 0.000, 0.000, 0.000, -.232, -.087, +.065, +.068, +.065
Color (Instrumental to SDSS system) (SDSS mag.) xx-xx, xx-xx, xx-xx, xx-xx, xx-xx, uS-gS , gS-rS , gS-rS , rS-iS , iS-zS
Dark sky brightness @ zenith - Moon 0% 22.70, 22.00, 21.30, 20.30, 19.40, 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, 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, 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, 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, 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, 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" 25.30, 25.70, 25.10, 24.70, 23.70, 25.60, 26.00, 25.50, 24.60, 23.40 (mag AB)
Field galaxy, SNR=10, 60mn, Dark, 0.8" 25.00, 25.20, 24.60, 24.30, 23.20, 25.10, 25.60, 25.00, 24.20, 23.00 (mag AB)
Transition from AB to Vega magnitude system -.346, +.092, -.171, -.401, -.554, -.621, +.087, -.181, -.392, -.526 (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/iS, ~15% in z/zS
New narrow band filters (same FOV) Halpha, HalphaOFF, OIII, OIIIOFF, CaH&K
Camera
Readout time (including overhead) ~40 seconds
Read noise (e- / pixel) ~5
Electronic chain 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) ~750
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