Contents
Basic parameters†
Spectroscopic mode†
Specifications for TAO†
| Parameter | I | J | H | K |
|---|
| Wavelength (μm) | 0.91-1.20 | 1.17-1.47 | 1.41-1.78 | 1.73-2.45 |
| Number of orders | 20 | 13 | 11 | 13 |
| Slit width and length (") | (0.5 x 1.5) or (1.0 x 1.5) or (1.5 x 1.5) |
| Wavelength Resolution (λ/Δλ) | ~2600 (0.35" slit) |
| Array size | 256 x 256 |
| Pixel scale | 0.32"/pixel |
| Limiting magnitude (Vega)‡ | 17.5 | 17.2 | 16.3 | 16.0 |
‡: 600 sec, S/N = 10, 0".35 slit, 0".5 seeing. Note that these are preliminary values.
Imaging mode†
- Note that NICE is basically unsuitable for imaging due to its narrow field of view and large number of bad pixels. NICE is intended to be used for photometric observations for flux calibration of spectroscopic observations.
Specifications for TAO†
| Parameter | Value |
|---|
| Optical magnification | 0.55 x telescope focal plane |
| Spatial resolution | 0.20"/pixel |
| Field of view | 50.26" x 50.26" |
| Filter | J, H, Ks, IJ (0.8-1.5 um), HK (1.4-2.5 um) |
Slit viewer†
Specifications for TAO†
| Parameter | Value |
|---|
| Product | BU-51LIR (Bitran corp.) |
| Detector | Sony ICX825 CCD |
| Field of View | 24.1" x 18.0" |
| Pixel size | 6.45 x 6.45 μm |
| # of pixels | 1360 x 1024 |
Efficiency†
- Due to the specifications of the NICE optical system, the incident light passes through a filter before reaching the slit viewer. Therefore, the throughput is the quantum efficiency of the CCD multiplied by the filter transmittance.
Overheads†
| Action | Time (min) |
|---|
| Acquisition | ? |
| Readout | 0.2 |
| Filter change | 1 |
| Cross disperser change | 1 |
| Slit change | ? |
| Focus adjustment | 10 |
Important notices†
Calibration lamp†
- Krypton and Argon lamps are used for wavelength calibration.
Bad pixel†
- Due to aging, the number of bad pixels has increased over the years. We have designed the echelle format to minimize the impact as much as possible, but some orders are severely affected.
- If the order of interest is heavily affected, it is possible to move it to an area with fewer bad pixels by adjusting the optics as a special process. However, in such cases, they are not subject to pipeline processing.
Atmospheric dispersion†
- Since the slit viewer is an optical camera and its wavelength range is different from that of NICE itself, the effect of atmospheric dispersion cannot be ignored for target acquisition.
- TBD.
Strange behavior of dark frames†
Sensitivity†
S/N vs. Integration Time†
Exposure Time Calculator (ETC)†
Data Analysis Pipeline†
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