The High Efficiency and Resolution Multi Element Spectrograph, HERMES, is a facility-class optical spectrograph for the Anglo-Australian Telescope (AAT). It is designed primarily for Galactic Archaeology, the first major attempt to create a detailed understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way. The goal of the GALAH survey is to reconstruct the mass assembly history of the Milky Way through a detailed chemical abundance study of one million stars. The spectrograph is based at the AAT and is fed by the existing 2dF robotic fiber positioning system. The spectrograph uses volume phase holographic gratings to achieve a spectral resolving power of 28,000 in standard mode and also provides a high-resolution mode ranging between 40,000 and 50,000 using a slit mask. The GALAH survey requires an SNR greater than 100 for a star brightness of V=14 in an exposure time of one hour. The total spectral coverage of the four channels is about 100 nm between 370 and 1000 nm for up to 392 simultaneous targets within the 2-degree field of view. HERMES has been commissioned over three runs, during bright time in October, November, and December 2013, in parallel with the beginning of the GALAH pilot survey, which started in November 2013. We present the first-light results from the commissioning run and the beginning of the GALAH survey, including performance results such as throughput and resolution, as well as instrument reliability.
The High Efficiency and Resolution Multi Element Spectrograph, HERMES is an facility-class optical spectrograph for
the AAT. It is designed primarily for Galactic Archeology , the first major attempt to create a detailed
understanding of galaxy formation and evolution by studying the history of our own galaxy, the Milky Way. The goal of
the GALAH survey is to reconstruct the mass assembly history of the of the Milky Way, through a detailed spatially
tagged abundance study of one million stars. The spectrograph is based at the Anglo Australian Telescope (AAT) and is
fed by the existing 2dF robotic fiber positioning system. The spectrograph uses VPH-gratings to achieve a spectral
resolving power of 28,000 in standard mode and also provides a high-resolution mode ranging between 40,000 to 50,000
using a slit mask. The GALAH survey requires a SNR greater than 100 for a star brightness of V=14. The total spectral
coverage of the four channels is about 100nm between 370 and 1000nm for up to 392 simultaneous targets within the 2
degree field of view. Hermes has been commissioned over 3 runs, during bright time in October, November and
December 2013, in parallel with the beginning of the GALAH Pilot survey starting in November 2013. In this paper we
present the first-light results from the commissioning run and the beginning of the GALAH Survey, including
performance results such as throughput and resolution, as well as instrument reliability. We compare the abundance
calculations from the pilot survey to those in the literature.
This paper describes the software systems implemented for the wide-field, automated survey telescope, SkyMapper. The
telescope is expected to operate completely unmanned and in an environment where failures will remain unattended for
several days. Failure analysis was undertaken and the control system extended to cope with subsystem failures,
protecting vulnerable detectors and electronics from damage. The data acquisition and control software acquires and
stores 512 MB of image data every twenty seconds. As a consequence of the short duty cycle, the preparation of the
hardware subsystems for the successive images is undertaken in parallel with the imager readout. A science data pipeline
will catalogue objects in the images to produce the Southern Sky Survey.
The Research School of Astronomy and Astrophysics (RSAA) of the Australian National University (ANU) at Mt Stromlo Observatory is developing a wide-field Cassegrain Imager for the new 1.3m SkyMapper Survey Telescope under construction for Siding Spring Observatory, NSW, Australia. The Imager features a fast-readout, low-noise 268 Million pixel CCD mosaic that provides a 5.7 square degree field of view. Given the close relative sizes of the telescope and Imager, the work is proceeding in close collaboration with the telescope's manufacturer, Electro Optics Systems Pty Ltd (Canberra, Australia).
The design of the SkyMapper Imager focal plane is based on E2V (Chelmsford, UK) deep depletion CCDs. These devices have 2048 x 4096 15 micron pixels, and provide a 91% filling factor in our mosaic configuration of 4 x 8 chips. In addition, the devices have excellent quantum efficiency from 300nm-950nm, near perfect cosmetics, and low-read noise, making them well suited to the all-sky ultraviolet through near-IR Southern Sky Survey to be conducted by the telescope.
The array will be controlled using modified versions of the new IOTA controllers being developed for Pan-STARRS by Onaka and Tonry et al. These controllers provide a cost effective, low-volume, high speed solution for our detector read-out requirements. The system will have an integrated 6-filter exchanger, and Shack-Hartmann optics, and will be cooled by closed-cycle helium coolers.
This paper will present the specifications, and opto-mechanical and detector control design of the SkyMapper Imager, including the test results of the detector characterisation and manufacturing progress.
We used FORS2 at UT2 of the VLT to obtain low resolution spectra of early type emission line stars in the field of the young open SMC cluster NGC 330. This cluster is known for its exceptional large number fraction of Be stars and could play a key role in constraining the Be phenomenon in general. 48 of the 59 program stars identified as H(alpha) excess sources by CCD imaging photometry can be confirmed to show H(alpha) line emission superimposed on a strong continuum. Comparison with VLT-FORS1 spectra collected a year earlier shows no or only a low significance of variability on the time scale of a year. To test the prediction of the hybrid model for global disk oscillations in Be star circumstellar disks we compared the number ratio of Be stars with asymmetric line profiles to the total number of Be stars with the known ratio of galactic field Be stars. About 10 of 47 emission line stars show asymmetric line profiles hence the theoretical prediction is not matched. We discuss several possibilities which might explain the discrepancy.
The fluorescence of natural constituents of bio-material may conceal its Raman spectra. This fluorescence is reduced by shifting the existing radiation to longer wavelengths. For several reasons the optimum is the excitation with 1064 nm radiation, produced by the Nd:YAG laser. In order to explore the applicability to medical diagnostics we installed an NIR-FT-Raman spectrometer in the 'Universitaetsklinikum Essen'. The results complied within 5 dissertations show that there are some useful potential applications in this field. However, much more work and, especially, international cooperation, is needed to develop this tool further for routine application.
The typical properties of the Raman spectrometers for the near-infrared range are discussed. Multiple monochromators, polychromators, and interferometers have specific advantages and disadvantages. They complement each other nicely.