Instrument Page
The conceptual design of the instrument was driven by the WEAVE science requirements, as defined by the Science Team, and translated to technical requirements by the Project and Instrument Scientists. The following table summarises the instrument characteristics:
Specification | Requirement | Goal | Design |
|---|---|---|---|
| Field of view diameter | 2 degrees | 2 degrees | 2 degrees |
| MOS multiplex | 800 | 1000 | 964/940 |
| Atmospheric dispersion compensation | 0.4-1.0 µm, 50oZD | 0.37-1.0 µm, 60oZD | 0.37-1.0 µm, 60oZD |
| MOS fibre aperture | >=1.2" | 1.5" | 1.3" |
| Open shutter efficiency (1 hour observations) | 70% | 90% | |
| Wavelength coverage | 400-950nm | 370-1000nm | *370-960nm |
| Spectral resolution (full simultaneous coverage) | 5000 | 5000 | 5000 |
| Spectral resolution (reduced coverage) | 20000 | 20000 | 20000 |
| Stray light as function of faintest target | <1% | ||
| Blue system efficiency | 20% | 25% | 25% |
| Red system efficiency | 25% | 30% | 30% |
| Multi-IFU multiplex | 10 | 30 | 20 |
| Multi-IFU FOV | 9" x 9" | 9" x 12" | 9" hex |
| Multi-IFU spaxel size | 0.8" | >1.2" | 1.3" |
| Single IFU FOV | 3' x 3' | 1.5' | |
| Single IFU spaxel size | 2.5" | Inner 1", outer 2.5" | 2.6" |
The philosophy behind the construction of WEAVE is to keep it simple but effective. Thus the design exploits the use of COTS (Commercial Off-The Shelf) components which not only reduces project costs and risks but provides an attractive solution for maintaining the instrument throughout its lifecycle.
The Instrument Block Diagram
The Instrument Block Diagram provides an high-level overview of the arrangement of the systems that comprise WEAVE. For readability, detailed component information is not represented here but the flow of data and signals are shown.
The WEAVE Instrument System
The WEAVE instrument consists of nine technical systems each of which is designed to deliver a specific functionality and provide appropriate interfaces to adjacent systems. The following table contains links to these technical systems:
| System Name | Description |
| Two-degree Prime Focus System | This system consists of the Prime Focus Corrector which includes the ADC, the instrument rotator and the focussing mechanism. |
| Fibre Positioner System | This system consists of the pick-and-place fibre positioner and it's software, the tumbler, the large IFU head and part of the acquisition and guidance subsystem. in addition to this, the Configure Tool is also part of this system. |
| Fibre Systems | This system consists of the MOS fibres, the IFU fibres and the guide fibres |
| Spectrograph System | This system consists of the spectrograph and the science detectors. |
| Observatory Control System | This system consists of the software for controlling all aspects of the instrument, with the exception of the Fibre Positioner, and automating the observations. |
| Core Processing System | This system consists of the quality control of the science data, the operational repository and full image processing and spectral extraction. |
| WHT support facilities | This system includes all the modifications that are required at the telescope to accept the instrument and calibration of the focal plane. |
| Advanced Processing System | This system consists of the software required to carry out high-level science analysis. |
| WEAVE Archive System | This system consists of the data archive. |