The science devices have 13.5 micron pixels = 0.33"/pixel at INT prime and each cover an area of 22.8 arcmin x 11.4 arcmin on sky. The total sky coverage per exposure is 0.29 sq deg.
The Loral autoguider has 15 micron pixels = 0.37"/pixel although charge adjacency effects limit the true Loral resolution to 30 microns.
Active area of EEV CCDs is 2048x4100 pixels, overscan regions give 2148x4128 pixels on readout, with Trimsec [51:2098,1:4100] and Biassec [1:50,1;4128] the recommended data and overscan sections for all devices.
Current readout time is 160s in SLOW mode (recommended) and 155s in STANDARD.
#1 Suffers from horizontal streaking from very bright stars and shadow
of radiation shield in bottom right hand edge
#2 Slight vignetting at top right
#3 Vignetted in bottom left corner
#4 "Shadow" of support screw in middle - flatfields out ok
For an example of a typical EEV42-80 QE curve (courtesy of Simon Tulloch) click here .
| Science CCD | Bias Level | Gain e-/ADU | Readout Noise e- | Max ADU |
|---|---|---|---|---|
| #1 | 1559 (1619) | 3.12 (3.12) | 7.9 (7.8) | 58,000 |
| #2 | 1636 (1667) | 3.19 (3.11) | 6.4 (7.1) | 59,000 |
| #3 | 1744 (1796) | 2.96 (2.98) | 8.3 (7.9) | 59,000 |
| #4 | 1190 (1219) | 2.22 (2.20) | 8.4 (7.9) | 58,000 |
Notes to table:
Measured using the default SLOW readout speed and FLASH clear.
The error on measuring the gain for each device is around 0.03 and the error on the readout noise measurement is about 0.3, ie. within the errors the gain and readout noise have remained constant.
Note that the gain of CCD#4 changed during a hardware fix early in October 1998 and is significantly different (2.2 cf. 3.3) from the value it had previously from the April 1998 commissioning.
| CCD | U | B | V | R | I |
|---|---|---|---|---|---|
| #1 | 23.8 | 25.6 | 25.7 | 25.6 | 24.9 |
| #2 | 23.8 | 25.6 | 25.6 | 25.6 | 25.0 |
| #3 | 23.6 | 25.6 | 25.6 | 25.6 | 25.0 |
| #4 | 23.6 | 25.6 | 25.7 | 25.6 | 25.0 |
Notes to table:
These zero-points are the magnitude of an object that gives 1 detected e-/s. The measurements were made during commissioning in April 1998 in less than perfect conditions, but should be accurate to 0.1 magnitudes.
U suffering from replaced 3rd corrector element which is not optimally coated - probably loses 0.2 magnitudes.
B,V,R are the Harris glass filters, U and I are RGO glass filters - see filter specifications for more details.
