HARMONI: first light spectroscopy for the ELT - procedure for adapting application programming interfaces (API) for systems engineering

HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450 nm to 2450 nm with resolving powers from R (≡λ/Δλ) 3500 to 18000 and spatial sampling from 60 mas to 4 mas. Typically, optical performance of instruments can be analytically verified through commercially available software such as Zemax OpticStudio. Zemax offers – Application Programming Interface (ZOS-API) to either Python, MATLAB, or with plugins for C# and C++. This paper discusses the development of a procedure for implementing the ZOS-API for the E-ELT instrument - HARMONI. It demonstrates how these interfaces were developed to assess the performance of optical systems, by computing the differential wavefront error across the field. The paper then highlights the advantages of utilizing these interfaces as a tool for Systems Engineering. The benefits include optical budget management, customizable analysis, end to end modelling and requirements verification.