Announcements
Detector Characteristics (ESPaDOnS)
GRACES is using the ESPaDOnS detector array, which consists of a 2kx4.5k deep-depletion e2v device called Olapa. The table below gives a summary of the current detector/controller characteristics.
| Array | e2v device Olapa |
| Pixel format | 2080x4640 |
| Pixel size | 13.5 μm square |
| Spectral response | ~0.34 to 1.03 μm |
| Bias level | Bias image |
| Flat field response | Flatfield image |
| Readout time | See observing overheads page |
| Dark current | 0.0126 é/pix/h |
| Saturation level | 65,535 ADU |
| Non-linearity | 0.4% at 46,400 ADU |
Readnoise and Gain Values
The table below gives the gain/read-noise values for the ESPaDOnS CCDs. 1 Amp mode (pre-17A):
| Readout mode | Gain (é/ADU) | Noise (é) | Read time (s) | Recommended for ... |
| Fast* | 1.6 | 4.7 | 32 | S/N (per frame) > 100 |
| Normal | 1.3 | 4.2 | 38 | 40 < S/N (per frame) < 100 |
| Slow | 1.2 | 2.9 | 60 | S/N (per frame) < 40 |
2 Amp mode (Amp A / B. This mode has been used since 17A):
| Readout mode | Gain (é/ADU) | Noise (é) | Read time (s) | Recommended for ... |
| Normal | 1.18 / 1.19 | 3.6 / 3.4 | 25 | S/N (per frame) > 40 |
| Slow | 1.03 / 1.01 | 2.5 / 2.5 | 36 | S/N (per frame) < 40 |
* FAST readout mode is not supported at Gemini.