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| 1 | +// ICD Subsystem |
| 2 | + |
| 3 | +subsystem = TEST2 |
| 4 | +title = "INFRARED IMAGING SPECTROGRAPH (IRIS)" |
| 5 | +modelVersion = "1.0" |
| 6 | + |
| 7 | +description = """ |
| 8 | +This is the API of the __InfraRed Imaging Spectrograph__ |
| 9 | +(TMT.INS.INST.IRIS). |
| 10 | + |
| 11 | +IRIS is an integral field spectrometer and imager working at the TMT |
| 12 | +diffraction limit, and is fed by the Adaptive Optics Facility, |
| 13 | +NFIRAOS. IRIS will operate over the wavelength range 0.8-2.5µm, and it |
| 14 | +must have an internal wavefront error (after compensation by NFIRAOS) |
| 15 | +better than 35 nm RMS. The field of view of the Integral Field Unit |
| 16 | +(IFU) will be 2’’, and the field of view of the imager will be at |
| 17 | +least 10’’x10’’ and possibly as large as 30’’x30’’. The imaging field |
| 18 | +of view may not be contiguous. Concurrent imaging and IFU observation |
| 19 | +is a goal. Plate scale will be adjustable to 4, 9 25, and 50 mas. The |
| 20 | +IFU spectral resolution will be R=4000 over the entire J, H and K |
| 21 | +bands, one band at a time, and the imaging mode will have R = 2-50. |
| 22 | + |
| 23 | +IRIS will have a set of three NGS wavefront sensors [2 tip-tilt (TT) + |
| 24 | +one tip/tilt/focus (TTF)], collectively called the On-Instrument |
| 25 | +Wavefront Sensor (OIWFS). The NFIRAOS sky coverage specification |
| 26 | +requires that TT(F) measurements be made in the science focal plane, |
| 27 | +where AO corrections make it possible to use fainter reference guide |
| 28 | +stars (J<22). The three wavefront sensors will be able to patrol the |
| 29 | +full 2’ corrected field produced by NFIRAOS. Further AO corrections |
| 30 | +are provided by up to four On-Detector Guide Windows (for NGSs on the |
| 31 | +IRIS Imager itself). |
| 32 | + |
| 33 | +An instrument rotator is used to compensate for the combination of |
| 34 | +sidereal rotation (changing parallactic angle between celestial and |
| 35 | +Alt-Az coordinates), and pupil rotation as the zenith angle changes. |
| 36 | + |
| 37 | +The OIWFS, ODGWs, and rotator are commanded by the AO Sequencer (AOSQ, |
| 38 | +part of the AO Executive Software), and follow demand streams produced |
| 39 | +by the TCS. |
| 40 | + |
| 41 | +All environmental control of IRIS is handled by the IRIS Instrument |
| 42 | +Sequencer. |
| 43 | +""" |
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