At first light, the NIR instruments of TMT will be assisted by a multi-conjugate adaptive optics instrument, known as the Narrow Field Infrared Adaptive Optics System (NFIRAOS). NFIRAOS will use laser guide stars for distortion correction in a field of view of 2 arcmin diameter, but natural guide stars will be required for tip/tilt correction. A catalogue of guide stars with NIR magnitudes as faint as 22 mags in J band (Vega system), covering the TMT-observable sky will be a critical resource for the efficient operation of NFIRAOS and no catalogue currently exists with objects so faint and cover the entire TMT observable sky. Hence it is essential to develop such a catalogue by computing the expected NIR magnitudes of stellar sources, identified in deep optical sky surveys, by using their optical magnitudes. In this paper, we will discuss a road map created for the generation of the Infrared Guide Star Catalogue (IRGSC) for the TMT using the optical data of stellar sources from the Pan-STARRS observations and computing their NIR magnitudes by using stellar atmospheric models and Spectral Energy Distribution (SED) fits. We have validated the computed NIR magnitudes of the sources in some fields by using the available NIR data for those fields. We find our method to be satisfactory, thereby creating a path for the final production of the IRGSC using the Pan-STARRS and put forward the challenges that need to be overcome in the future development of IRGSC.
The Thirty Meter Telescope (TMT) is a proposed future generation telescope which will be located on either Maunakea, Hawaii or La Palma in the Canary islands. A thermal-infrared (TIR) imager and spectrometer (MICHI) combined with an adaptive optics system is being investigated as a possible second-generation instrument for this telescope. MICHI has been designed to also have a polarimetry capability in both imaging and low dispersion spectroscopic modes. Using polarization ray tracing in Zemax, we have estimated the instrumental polarization (IP) and crosstalk introduced at the focus of the near- and mid-infrared imaging system. In our calculations, we find that the IP varies from 1.0-0.54% and 0.54-0.42%, whereas the polarization crosstalk varies between 25-4% and 4-0.7%, in the near and TIR regions respectively at the instrument port of MICHI. These values of IP and crosstalk may cause problems during the high absolute accuracy polarization observations. Here we present the polarization effects for the imaging system of MICHI and it impacts on the polarization observations.
Initially the primary mirror of the 3.6m Devasthal Optical Telescope is uncoated polished zerodur glass supplied by Lytkarino Optical Glass Factory, Russia/Advanced Mechanical and Optical Systems, Belgium. In order to do the aluminium coating on the primary mirror the coating plant including washing unit is installed near the telescope (extension building of telescope) by Hind High Vacuum (HHV) Bangalore, India. Magnetron sputtering technique is used for the coating. Several coating trials are done before the primary mirror coating; samples are tested for reflectivity, uniformity, adhesivity and finally commissioned. The primary mirror is cleaned, coated by ARIES. We present here a brief description of the coating plant installation, Mirror cleaning and coating procedures and the testing results of the samples.
A 3.6m aperture telescope has been installed at Devasthal recently and once commissioned this would be the largest optical telescope in India. The integration of the telescope was carried out by lifting the components from inside the telescope building. To make this possible, the position of the telescope was shifted by 1.85m from the dome centre at an angle of 255 degree with respect to the north. This posed a serious challenge in synchronizing the dome with the telescope movement. In this contribution we will be presenting the synchronization algorithm and dome control software.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.