Pixel Size: 21x21 microns
Pixel Scale: 0.60 arcsec/pixel
Chip Size: 2048 x 2048
Digital Limitation: 65,534
Bias Level: ~650 (gain=#4)
Preflash, e-: none
Dwell Time, microsec: 2 3 5 8 15
Noise, e-/RMS: ? ? 20 14-15 9-10
Gain, e-/ADU: 9.8 6.5 3.9 2.5 1.3
Gain, Index#: 1 2 3 4 5
Linearity,0.1%,e-: ~210,000
Linearity,1.0%,e-: ~230,000
Column Spillover, e-: ~240,000
Internal Radiation Event Rate, Events/HR: ~2700
Dewar Temp. deg C: ~-107
CCD Temp. deg C: ~-99
Dark Current, e-/hr/pix: ~5-10
Hot Columns: [1571:1571,1134:2048] bias
                     : [2066:2066,1:2048] in overscan region, see comment below
Low Columns: [1103:1103,744:2048] flat field

The quantum efficiency of S2KB is given in this figure. The abscissa is wavelength in nanometers and the ordinate is dQE (%).

Here are some of the original calibration frames for S2KB.

• Bias Frame
• B dome flat
• V dome flat
• R dome flat
• I dome flat
• H-alpha dome flat

There is a hot column in the overscan region, [2066:2066,1:2048]. Check for the presence and position of this column in your data. You will probably NOT want to use the default BIASSEC in CCDPROC, but rather set BIASSEC to [2053:2064,1:2048] or a similar region of your choosing.

More recently, S2KB has developed an enhanced bias level in one corner amounting to a peak of ~1500 ADU above an overall level of ~965 ADU. This bias exposure shows this effect. The enhancement is limited to the region X < ~240 pix and Y> ~1800 pix.

You can estimate exposure times for S2KB using the CCDTIME package in IRAF v2.11.3 which should still have the necessary information in its ccdtime$kpno.dat database file. If it does not, here is the kpno.dat file.

Click here for the latest on scattered light and over-illuminiation.

Filters

Each filter is 4x4 inches square.

The passbands of the most commonly used filters are collected (and shown graphically) in a single spreadsheet for convenience:

• common filter spreadsheet (.xlsx)