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Anna MacIver

Publications and source records attributed to Anna MacIver.

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HARMONI at ELT: Developing a Modular Review Process using TRIZ

HARMONI is the first light, adaptive optics assisted, near-IR integral field spectrograph for the ELT. It covers a spectral range from 800nm to 2450nm with resolving powers from 3000 to 7000 and spatial sampling of 25mas and 6mas. It can operate in two adaptive optics modes - SCAO (including a high contrast capability) and MCAO. The project is resuming its final design phase after a rescope design phase in 2025. The HARMONI team at UKATC have been pioneering the use of TRIZ by managing monthly TRIZ workshops to tackle significant project problems that arise. This TRIZ case study investigates how design changes of HARMONI can be reviewed effectively and efficiently. It draws on how the review process of Ground Based Astronomy projects can be improved to add quality to the successful creation of an instrument while reducing strain on designers and reviewer's time. To address resource-intensive and document-driven review processes, the case study utilised TRIZ techniques including: thinking in time and scale technique: the 40 inventive principles to tackle design contradiction: function analysis and size, time, cost analysis. The solution developed considered a modular, continuous review process focusing on specific subsystems or technical topics as they mature while encouraging a live review culture, where stakeholders and expert reviewers are engaged continuously through informal check-ins rather than infrequent formal meetings.

astro-ph.IM

HARMONI at ELT: line spread functions in a diffraction limited spectrometer

HARMONI is the first light, adaptive optics assisted, near-IR integral field spectrograph for the ELT. It covers a spectral range from 800~nm to 2450~nm with resolving powers from 3000 to 7000 and spatial sampling of 25~mas and 6~mas. It can operate in two adaptive optics modes - SCAO (including a high contrast capability) and MCAO. The project is resuming its final design phase after a rescope design phase in 2025. Diffraction of the pupil becomes significant in a spectrograph where the slit width is comparable to the diffraction limited PSF. When the spatial coherence due to the narrow slit is considered, the resulting line spread function can be narrower than the geometric width of the input slit, with a non-linear dependence on the size of the pupil aperture after the slit. We outline the impact of these diffraction and spatial filtering effects on the line spread function of HARMONI and identify parameters that should be considered when designing a diffraction limited spectrograph.

astro-ph.IM