Wednesday 26^th February OCW017 1pm

Speaker:  Jay Stephan, UKATC

Title: Airglow and sky-subtraction in the ELT era

Abstract: Airglow is the emission of light from chemical reactions in the upper atmosphere. This light is imprinted on all ground-based observations and needs to be carefully removed with ‘sky-subtraction’ to retrieve accurate science data. However, airglow is complex and poorly characterised – mainly faint lines are uncatalogued, and questions exist over its temporal and spatial variation. In this talk I will discuss how preparations are being made to enable accurate sky-subtraction for ESO’s upcoming 39m Extremely Large Telescope (ELT), required to unlock the telescope’s full science potential and immense sensitivity. I will discuss our understanding of airglow; the techniques used in sky-subtraction for upcoming multi-object spectrographs; and the research that is being carried out in characterising airglow (which includes pointing an 8m telescope at zenith for 39 hours).

Speaker:  Serge Meimon, Onera

Title:  High Angular Resolution in Complex Media : Dealing with Aberrations and Scattering"

Abstract:  Aberrations and scattering are typically treated separately: we correct for turbulence-induced aberrations, while scattering is often considered either as transmission loss or a source of background noise. In this talk, I will highlight the common origin of both phenomena, present cases where scattered light can be leveraged to enhance contrast, and finally, discuss the possibility of correcting scattering in a manner similar to how aberrations are traditionally corrected.

Speaker is Dmitry Morozov (University of Glasgow). Title is TBC.

Speaker is Peter Wizinowich (KECK). Title is TBC.

Speaker is Ellen Schallig (University of Oxford). The seminar is titled 'Braiding Glass: Building an Integral Field Unit for the WEAVE Instrument'.

WEAVE, the new spectroscopy facility on the William Herschel Telescope, had first light in 2022, and has been collecting great data since. In this talk, I will look back on the building of WEAVE, and in particular of its Large Integral Field Unit (LIFU). I will take you through some of the surprises that we encountered in manipulating fibres, and the actual effort it takes to put hardware together with the necessary precision. Finally, we will look at those first-light results from the perspective of the LIFU.

Speaker is Doug McDonald (Fraunhofer IOSB). Title is TBC.