MOIRCS Instrument Parameters
| Detectors | HAWAII-2 2048x2048 x 2 |
| Pixel size | 18 um |
| Pixel scale(1) | 0.1170'' |
| Field of view | 3.94' x 6.90' (2) |
| Gain(3) | 3.50 e-/ADU @ Channel 1 (Sci #96) 3.33 e-/ADU @ Channel 2 (Sci #64) |
| Dark current | < 0.1 e-/s |
| Saturation level | 146 000 e- (chip 2) (4) |
| Read noise | ~30 e- rms(5) |
| Number of amplifiers per detector | 4 |
| Minimum Exposure(6)(7) | 11.5 s (NDUMMYREAD=0) 19.7 s (NDUMMYREAD=2) |
| Filter exchange time | 15~60 sec |
| MOS | |
|---|---|
| Number of available mask slots | up to 21 (15 for users) |
| Typical number of slits per mask | 30~50(8) |
| Days needed for cooling mask | > 2 whole days |
| MOS aquisition time | about 25 min.(9) |
(1) The value is valid for the distortion-corrected data processed by the geometric transformation database supplied by the observatory(see here for more detail). In raw image, pixel scale changes with the distance from the optical center due to distortion.
(2) About 0.4 arcmin2 is vignetted in the field of view of 4' x 7' (Please see the FOV page).
(3) Based on the measurement in Nov 2008.
(4) We recommend to keep the net count of the data to within 20000 ADU under the CDS readout mode for usual scientific exposure. See the detector information page for detail.
(5) Readnoise can be suppressed to about 15 e- rms by using the multi-sampling readout mode (see the detector information).
(6) The operation under NDUMMYREAD=2 is recommended.
(7) Though the Partical Readout mode is available to reduce the minimum exposure time, it is currently not recommended to use. For more detail, see the Information page.
(8) Assuming the typical length of slitlets of 10-20 arcseconds.
(9) Please also see the MOS page. The acquisition time for Long slits can be shorter than this.
FITS Header Keywords
Here are the examples of the MOIRCS FITS headers as of 2015, i.e., old MOIRCS.
Please note that all data on these pages are subject to change as the evaluation of the performance of MOIRCS progresses.
Updated 2014-06-04