HARMONI: A Narrow Field Near-infrared Integral Field Spectrograph for the E-ELT
SCIENCE WITH THE VLT IN THE ELT ERA (2009) 267-+
Exploring high contrast limitations for image slicer based integral field spectrographs
Proceedings of SPIE - The International Society for Optical Engineering 7015 (2008)
Abstract:
Current simulation and experimental investigatory work is going on into the performance of slicer and lenslet IFS designs. The aim of this work is to determine which technology holds the best promise for achieving the highest contrasts with EPICS on the E-ELT. Results from Spectral Deconvolution methods for high contrast detections are presented, both on sky images from AB Dor C observations using SINFONI on the VLT and improvements to the algorithms made through use of EPICS simulation data. Using these simulations, only containing photon and speckle noise, we have been able to detect simulated planets down to a contrast of 1010 located less than 1" from the parent star. The effects of spectral resolution and wavelength range on high contrast observations are discussed. Shortening the wavelength range increases the inner working angle. It is seen that an outer working angle is also reached that decreases with spectral resolution. The limit on the inner working angle can be overcome partly by increasing the wavelength range of the instrument although another inner working angle limit will be reached if a coronagraph is used. The limit of the outer working angle can also be overcome by increasing the spectral resolution of the instrument or possibly by making an IFS that produces an output with a constant spectral resolution, R,instead of constant Δλ.This is still a work in progress.The globaljetwatch spectrographs: A fibre-fed spectrograph for small telescopes
Proceedings of SPIE - The International Society for Optical Engineering 7014 (2008)
Abstract:
The GlobalJetWatch project (www.globaljetwatch.net) will place small (0.5-metre) commerical telescopes in four schools around the world. Each telescope will be equipped with a custom designed spectrograph, currently being built by the Astrophysics sub-department of the University of Oxford. The scientific goal of the project is to provide continual monitoring of a rosetta stone object, the micro-quasar SS433. In addition,the project has a significant out-reach element, aiming to involve school children on four-continents in front-line astronomical research. The spectrograph is a fibre-fed fixed format cross-dispersed echellete design providing R 6000 spectra from 4300-8500Å in a single exposure. The spectrograph is built almost entirely from off-the-shelf components. The four GlobalJetWatch sites (Australia, India, South Africa,Chile) will be commissioned in 2008/09. Here we present the baseline design of the spectrograph, and initial results from the prototype on-sky commissioning in Oxford.SWIFT de-magnifying image slicer: Diffraction limited image slicing at optical wavelengths
Proceedings of SPIE - The International Society for Optical Engineering 7018 (2008)
Abstract:
We present the manufacturing and first results from testing and characterising the SWIFT image slicer. The SWIFT image slicer design is based on the MPE-3D and SPIFFI image slicers. It uses plane mirrors to slice the input field but through a novel, de-magnifying design, using a mosaic of spherical lenses, it achieves a considerable de-magnification. Classical polishing techniques can be applied to manufacture both plane and spherical surfaces with very high surface accuracy and quality reducing aberrations and scattered light. The SWIFT image slicer was manufactured over a 18 months period and was delivered to Oxford in September 2007. The commissioning of the SWIFT instrument will take place in August/September 2008.Fifteen new T dwarfs discovered in the UKIDSS Large Area Survey
Monthly Notices of the Royal Astronomical Society 390:1 (2008) 304-322