Delivery and integration of MEGARA at GTC: the process of going from laboratory to the telescope

Abstract

MEGARA is an IFU & MOS medium-resolution spectrograph that finished its commissioning at the GTC 10m telescope on August 2017. MEGARA is a fiber-fed high-resolution spectrograph with two major units, Fiber-MOS & Spectrograph, that are now located at the Folded-Cass F and Nasmyth-A foci of GTC respectively. These are linked by more than 1200 fibers 44.5m-length split between two observing modes, the LCB (Integral Field Unit, IFU) and a Multi-Object (MOS) capability with 92 robotic positioners each one provided with a mini-bundle of 7 fibers. The spectrograph can accommodate 18 VPHs (11 of them can be simultaneously mounted) covering the visible wavelength range at Resolving Powers between R=6000-20000. This paper presents the sequence of tasks carried out after Laboratory Acceptance at the Universidad Complutense de Madrid to move the whole instrument to the GTC. A detailed day-to-day plan was followed to disassemble, pack, transport, reintegrate the full instrument at the GTC and to verify performance to ensure the instrument was ready for commissioning. The lessons learnt are relevant to other double-focus instruments being developed such as WEAVE@WHT or PFS@Subaru.