NIRSPEC - The Near Infrared Echelle Spectrograph
Principal Investigator: Ian S. McLean (UCLA), Michael P. Fitzgerald (UCLA)
References:
The Design and Development of NIRSPEC: A Near-Infrared Echelle Spectrograph
for the Keck II Telescope, Ian S. McLean et al., 1998, SPIE
vol. 3354, pp. 566-578.
Optical design of the slit-viewing camera for the NIRSPEC upgrade, Emily C. Martin et al., 2016,SPIE vol. 9908
An overview of the NIRSPEC upgrade for the Keck II telescope, Emily C. Martin et al., 2018, SPIE vol. 10702
Characterization and performance of the upgraded NIRSPEC on the W. M. Keck Telescope, Ronald A. López et al., 2020, SPIE vol. 11447
Overview:The Near Infrared Spectrometer (NIRSPEC), a cryogenic cross-dispersed echelle spectrograph, features spectroscopy over the 0.96-5.5 micron range at low and high resolving powers, R ~2000 and R ~25,000. The slit-viewing camera provides additional capability to image the slit field in a 40 x 40 arcsecond FOV from 0.95 - 5.5 microns. The software interface includes planning tools for users to prepare observational setups and exposure sequences. NIRSPEC was upgraded in 2018 with new detectors and a modern control system.
Detector Characteristics
Updated: December 2020
| Slit-viewing Camera (SCAM) | |
| Detector | Teledyne H2RG 256x256 (sub-arrayed) |
| Plate Scale | 0.157 ± 0.001 "/pixel |
| Gain | 10.9 e-/ADU (measured) |
| Read Noise | 130 e- (preliminary) |
| Linear Limit | 10,000 ADU |
| Minimum Integration | 0.67 sec in CDS mode |
| Charge Persistence | negligable |
| Field of View | 40" square field |
| Wavelength Sensitivity | 0.95 - 5.5 microns |
| SCAM detector layout | low resolution diagram |
| high resolution diagram | |
| Spectrograph (SPEC) | |
| Detector | Teledyne H2RG 2048x2048, 18 micron pixels |
| Gain | 3.01 ± 0.08 e-/ADU |
| Read Noise | 11.56 e- (3.84 ADU, MCDS 16) |
| Dark Current | 0.70 ± 0.004 e-/s |
| Linear Limit | 25,000 ADU |
| Minimum integration | 1.5 sec in CDS mode |
| Charge Persistence | negligable |
| Wavelength Sensitivity | 0.95 - 5.5 microns |
| SPEC detector layout | low resolution diagram |
| high resolution diagram | |
Filter Information
Measured Spectral Dispersion
Basic NIRSPEC Specifications
| Location | RNAS, Keck-2, f/15 input beam |
| Spectroscopy: | Low resolution: R=2000 (150 km/s), 3-pixel slit (0.38") |
| High resolution: R=25,000, 4.5-pixel slit (0.43") | |
| Low-Res Slits: | 42x0.380" (3-pix) |
| 42x0.570" (4.5-pix) | |
| 42x0.760" (6-pix) | |
| High-Res Slits: | 0.144"x12 (1.5-pix) |
| 0.288"x12 (3-pix) | |
| 0.432"x12 (4.5-pix) | |
| 0.576"x12 (6-pix) | |
| 0.720"x12 (7.5-pix) | |
| 0.288"x24 (3-pix) | |
| 0.432"x24 (4.5-pix) | |
| 0.720"x24 (7.5-pix) | |
| Annular Guider: | 1024x1024 MAGIQ, 0.20 arcsec pixels, annular FOV. Filters: V, R, I, RG780, ND: Open, ND1, ND2, ND3, ND4 |
| Guiding with SCAM not avaiable. | |
| Optics: | Spectrograph optics all reflecting, diamond-machined, post-polished, Al/Ni-Al substrates, silver or gold coated. |
| Cryogenics: | Full vacuum enclosure, CCR continuous cooling to ~55 K (30 K for the H2RGs). |
| All cryogenic mechanisms, including image derotator to fix sky PA on slit. | |
| Electronics: | Linux-based architecture. |
| User Interface: | Python (mechanism control,quicklook & target acquisition) and IDL (echelle format simulator, calibration GUI). |
| Performance: | SCAM image quality FWHM 0.3-0.55" typical. |
| SCAM J-band zero point: 24.7 mag @ 1 DN/s. | |
| Complete performance details for SPEC here. |
Additional Information
| Web & Contact | |
| WWW sites: | NIRSPEC Home Page |
| UCLA NIRSPEC Page | |
| CARA contact: | Instrument |
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